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Designing Interactive
A comprehensive guide to HCI, UX and interaction design

David Benyon



Designing Interactive Systems


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Designing Interactive
A com prehensive guide to HCI, UX and interaction design

David Benyon

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First published 2005 (print)
Second edition published 2010 (print)
Th ird edition published 2014 (print and electronic)
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© Pearson Education Limited 2014 (print and electronic)
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Brief contents
Guided tour
Publisher's acknowledgements


12 Visual interface design


13 Multimodal interface


Part III
Contexts for designing
interactive systems


14 Designing websites


15 Social media


16 Collaborative environments


17 Agents and avatars


18 Ubiquitous computing


19 Mobile computing


20 Wearable computing


Part IV
Foundations of designing
interactive systems


21 Memory and attention



22 Affect


7 Understanding


23 Cognition and action


8 Envisionment


24 Social interaction


9 Design


25 Perception and navigation




P a rti
Essentials of designing
interactive systems
1 Designing interactive systems:
a fusion of skills


2 PACT: a framework for designing
interactive systems


3 The process of human-centred
interactive systems design


4 Usability


5 Experience design


6 The Home Information Centre (HIC):
a case study in designing
interactive systems

Part II
Techniques for designing
interactive systems

10 Evaluation


11 Task analysis


Guided tour
Publisher's acknowledgements



Part I
Essentials of designing
interactive systems


Introduction to Part I


1 Designing interactive system s:
a fusion of skills




1.1 The variety of interactive systems


1.2 The concerns of interactive systems design


1.3 Being digital


1.4 The skills of the interactive systems designer 18
1.5 Why being human-centred is important


Summary and key points
Further reading
Web links
Comments on challenges


2 PACT: a fram ew ork for designing
interactive system s



3 The process of human-centred
interactive systems design




3.1 Introduction


3.2 Developing personas and scenarios


3.3 Using scenarios throughout design


3.4 A scenario-based design method


Summary and key points
Further reading
Web links
Comments on challenges


4 Usability




4.1 Introduction


4.2 Accessibility


4.3 Usability


4.4 Acceptability


4.5 Design principles


Summary and key points
Further reading
Web links
Comments on challenges



5 Experience design


2.1 Introduction




2.2 People


5.1 Introduction


2.3 Activities


5.2 Engagement


2.4 Contexts


5.3 Designing for pleasure

2.5 Technologies


5.4 Aesthetics


2.6 Scoping a problem with PACT


5.5 Service design


Summary and key points
Further reading
Web links
Comments on challenges


Summary and key points
Further reading
Web links
Comments on challenges




6 The Home Information Centre
(HIC): a case study in designing
interactive systems




6.1 Introduction


6.2 Scenarios for the HIC


6.3 Evaluating early interface prototypes


6.4 A first design


6.5 The second interface design


Summary and key points
Further reading
Web links
Comments on challenges


Part II

Summary and key points
Further reading
Web links
Comments on challenges


9 Design




9.1 Introduction


9.2 Conceptual design


9.3 Metaphors in design


9.4 Conceptual design using scenarios


9.5 Physical design


9.6 Designing interactions


Summary and key points
Further reading
Web links
Comments on challenges


10 Evaluation




Techniques for designing
interactive systems


Introduction to Part II


10.1 Introduction


7 Understanding


10.2 Expert evaluation




10.3 Participant-based evaluation


7.1 Understanding requirements


10.4 Evaluation in practice


7.2 Participative design


10.5 Evaluation: further issues


7.3 Interviews


7.4 Questionnaires


7.5 Probes


Summary and key points
Further reading
Web links
Comments on challenges



7.6 Card sorting techniques


7.7 Working with groups


7.8 Fieldwork: observing activities in situ


11 Task analysis

7.9 Artefact collection and 'desk work'




Summary and key points
Further reading
Web links
Comments on challenges


11.1 Goals, tasks and actions


11.2 Task analysis and system design


11.3 Hierarchical task analysis


11.4 GOMS: a cognitive model of procedural


11.5 Structural knowledge



11.6 Cognitive work analysis


8.1 Finding suitable representations


8.2 Basic techniques


8.3 Prototypes


8.4 Envisionment in practice


Summary and key points
Further reading
Web links
Comments on challenges







12 Visual interface design




12.1 Introduction


12.2 Graphical user interfaces


12.3 Interface design guidelines


12.4 Psychological principles and
interface design


12.5 Information design


12.6 Visualization


Summary and key points
Further reading
Web links
Comments on challenges


13 Multimodal interface design




13.1 Introduction


13.2 Interacting in mixed reality


13.3 Using sound at the interface


13.4 Tangible interaction


13.5 Gestural interaction and surface


Summary and key points
Further reading
Web links
Comments on challenges


Part III
Contexts for designing
interactive systems


Introduction to Part III




Designing w eb sites



14.1 Introduction


14.2 Website development


14.3 The information architecture of


14.4 Navigation design for websites


14.5 Case study: designing the Robert Louis
Stevenson website


Summary and key points
Further reading
Web links
Comments on challenges


15 Social media




15.1 Introduction


15.2 Background ideas


15.3 Social networking


15.4 Sharing with others


15.5 The developing web


Summary and key points
Further reading
Web links
Comments on challenges


16 Collaborative environments




16.1 Introduction


16.2 Issues for cooperative working


16.3 Technologies to support cooperative


16.4 Collaborative virtual environments


16.5 Case study: developing a collaborative
tabletop application


Summary and key points
Further reading
Web links
Comments on challenges


17 Agents and avatars




17.1 Agents


17.2 Adaptive systems


17.3 An architecture for agents


17.4 Applications of agent-based


17.5 Avatars and conversationalagents


Summary and key points
Further reading
Web links
Comments on challenges





18 Ubiquitous computing




18.1 Ubiquitous computing


18.2 Information spaces


18.3 Blended spaces


18.4 Home environments


18.5 Navigating in wireless sensor networks


Summary and key points
Further reading
Web links
Comments on challenges


19 Mobile computing




19.1 Introduction




Context awareness

19.3 Understanding in mobile computing


19.4 Designing for mobiles
19.5 Evaluation for mobile computing


Summary and key points
Further reading
Web links
Comments on challenges


20 Wearable computing




20.1 Introduction


20.2 Smart materials


20.3 Material design


20.4 From materials to implants


Summary and key points
Further reading
Comments on challenges


Part IV
Foundations of designing
interactive systems
Introduction to Part


21.3 Attention


21.4 Human error


Summary and key points
Further reading
Web links
Comments on challenges


22 Affect




22.1 Introduction


22.2 Psychological theoriesof emotion


22.3 Detecting and recognizing emotions


22.4 Expressing emotion


22.5 Potential applications and key
issues for further research


Summary and key points
Further reading
Web links
Comments on challenges


23 Cognition and action




23.1 Human information processing


23.2 Situated action


23.3 Distributed cognition


23.4 Embodied cognition


23.5 Activity theory


Summary and key points
Further reading
Web links
Comments on challenges


24 Social interaction




24.1 Introduction


24.2 Human communication


24.3 People in groups


24.4 Presence



24.5 Culture and identity


Summary and key points
Further reading
Web links
Comments on challenges







21 Memory and attention

21.2 Memory



25 Perception and navigation




25.1 Introduction


25.2 Visual perception


25.3 Non-visual perception


25.4 Navigation


Summary and key points


Further reading
Web links
Comments on challenges





Companion Website
For open-access student resources specifically written
to complement this textbook and support your learning,
please visit

Lecturer Resources
For password-protected online resources tailored to support
the use of this textbook in teaching, please visit


G uided tour








Parts: the book is split
into four parts, each with
a part opener describing
the main themes and links
between chapters within
that part.


Part l
Essentials of designing
interactive systems
1 Designrig interoclr*e system s a lusion o< state 5
2 PACT a fromework tor designing interoctive system s ?s
3 The process o( hum arxentred rteroctrve systems
design u
4 UsabWy H
5 Experience design n
6 The Home Information Centre H Q : a case study in
designng interactive system s to*

Chapter aims introduce
topics covered and
summarize what you
should have learnt by the
end of the chapter.

Guided tour

Challenges encourage
students to apply their
understanding by
completing practical tasks
and asking questions
about topics discussed.
Chapter linking arrows
highlight the connections
between chapters and
indicate where you can
find further details about
a topic or concept.
Further thoughts invite you to think
in more depth about certain topics.

Boxes provide real-world
examples to further
illustrate topics and
issues. These entertaining
applications help to
clarify and extend a
student’s understanding.

Screenshots, figures
and photos feature
throughout the text to
illustrate key points and
clarify topics discussed.




Guided tour


Exercises, practical challenges
and tasks feature at the end of
every chapter to test students’
understanding and encourage
them to apply their knowledge.

Comments on challenges
provide guideline answers to
chapter challenges.

Designing Interactive Systems is aimed squarely at the next generation of user experi­
ence (UX) and interactive system designers. This book presents a comprehensive intro­
duction to the practical issue of creating interactive systems, services and products
from a human-centred perspective. It develops the principles and methods of hum ancomputer interaction (HCI) and Interaction Design (ID) to deal with the demands of
twenty-first-century computing and the demands for improved user experience (UX).
UX and ID are concerned with the design of websites, desktop applications, smart­
phone apps, ubiquitous computing systems, mobile systems, wearable systems and
systems to support cooperation between people. UX and ID are concerned with the
development of novel apps, visualizations, auditory displays and responsive environ­
ments. HCI is about how to design for these experiences in a human-centred way that
takes account of human abilities and preferences and ensures that systems are acces­
sible, usable and acceptable.
This book aims to be the core text for university courses in HCI, ID and UX design. It
contains the core material for introductory courses and advanced material and links to
other resources for final-year undergraduate and masters-level students and to meet the
needs of usability and UX professionals working in industry.
HCI established itself as an important area of study in the early 1980s and by the
early 1990s there was a coherent syllabus and several textbooks. In the early 1990s
the ‘world wide’ Web appeared, opening up website design as a new area. Information
architecture and information design emerged as important areas of study and new
issues of usability became important in the open and untamed world of the Web. By the
late 1990s mobile phones had become a fashion statement for many people; style was as
important as function. With colour displays and better screens, mobile phones became
increasingly programmable. Interaction designers were needed along with software
engineers to create exciting experiences for people. Smartphones, tablet computers and
other information appliances made further new demands on software developers. User
interfaces became tangible, graspable and immediate and software systems had to be
engaging as well as functional. So, came the era of user experience (UX) design. Digital
technologies, wireless communications and new sensing devices provided new media
for a new generation of artist-designers involving whole installations, new modalities
of interaction and wearable computing.
All this has brought us to where we are today: a dynamic mix of ideas, approaches
and technologies being used by lots of people doing very different things in different
contexts. Designing Interactive Systems aims to focus this emerging discipline by bring­
ing together the best practice and experience from HCI, UX and ID. Designing Interactive
Systems presents a human-centred approach to interaction and experience design. The
strength and tradition of HCI has been in its human-centredness and usability concerns.
HCI has evolved methods, guidelines, principles and standards to ensure that systems
are easy to use and easy to learn. ID has come from design schools, applying traditional
approaches to design that emphasize research, insight and critical reflection. UX has
emerged during the Internet era to emphasize the enjoyment and engagement of the
whole interactive experience.

Practitioners of HCI, website designers, usability experts, user experience designers,
software engineers - indeed all those concerned with the design of interactive systems
in all their forms - will find much that they recognize in this book. It is concerned with
how to design engaging interactions between people and technologies to support the
activities that people want to do and the contexts in which they act.

Organization of the book for the 3rd edition
The second edition of Designing Interactive Systems: a comprehensive guide to HCI and
interaction design established itself as the key text for students and professionals of
interaction design (ID), user experience (UX) and human-computer interaction (HCI).
It has been translated into Chinese, Portuguese and Italian, ensuring it has real interna­
tional coverage. This new edition aims to bring the material right up to date and to set
the agenda for the future.
The previous edition established a clear structure for presenting the curriculum for
HCI, ID and UX. The material was organized into four parts.
• Part I focused on the essentials of designing interactive systems.
• Part II covered the key techniques for human-centred interaction design that a good
designer should master.
• Part III focused on the different contexts for interaction design.
• Part IV provided the psychological and sociological foundations of the subject.
reviewed this structure and overall reviewers and students liked it. Some argued
that foundations should come first, but providing the essentials first makes the book
more accessible. Some argued that the structure of the book should follow the structure
of a design project, but interactive systems design projects are so various that there is
no one structure that reflects this variety. Others felt that there were too many different
techniques and that the book should be more prescriptive.
Taking all these issues on board and looking at the changes that have happened in
the subject since the second edition has resulted in this current edition. The four-part
structure - essentials, techniques, contexts and foundations - remains. This allows pro­
fessors and tutors to pick the combination that suits their classes best. Some suggestions
are given below. The two chapters on the contextual design method have been removed,
with the most important techniques from that method distributed across the relevant
chapters. As the contexts in which designing interactive systems takes place continue to
change so all the chapters in Part III have been thoroughly revised and a new chapter on
wearable computing has been added. Every chapter has been revised in the light of this
rapidly changing subject and all the examples have been updated to reflect changing
Thus Designing Interactive Systems now has the following structure.
Part I provides an essential guide to the issues of designing interactive systems - the
main components of the subject, key features of the design process and how these are
applied to different types of system. The unifying idea is encapsulated by the acronym
PACT: designers should strive to achieve a harmony between the needs of different

people who undertake activities in contexts using technologies. It is the very large
amount of variation in these components that makes designing interactive systems such
a fascinating challenge. A key concept throughout is the idea of ‘scenarios’. Scenarios
are stories about interactions. They provide an effective representation for reflecting on
a design throughout its development. All the material has been updated and new mate­
rial has been added to Chapter 4 on accessibility. The chapter on experience design has
been extended to cover gamification and service design.
Part II pulls together all the main techniques arising from HCI, ID and UX that are used
for understanding, designing and evaluating interactive products, services and experiences.
Part II presents techniques for understanding the requirements of interactive systems,
probing people for ideas, getting people to participate in the design process, card sorting
to develop information architectures and investigating similar systems for ideas. Part II
includes a chapter on ways of envisioning ideas, prototyping and evaluating design ideas.
A more formal approach to conceptual and physical design is included along with a chap­
ter on the key HCI technique of task analysis and a detailed presentation of user interface
design in two chapters. One chapter focuses on design of visual interfaces and the other on
multimodal interfaces that include sound, touch and gesture.
Part III considers interaction and experience design in the different contexts that
are dominating the subject today. There is a chapter on website design and another on
social media. But ID and UX go way beyond displays on a desktop computer. People are
using mobile devices and interacting with interactive environments. Accordingly, Part
III includes chapters on designing for mobile and ubiquitous computing. There is also
a new chapter on wearable computing. Collaborative environments and agent-based
interaction are also important emerging contexts for UX, ID and HCI.
Part IV provides a deep treatment of the psychological foundations of HCI, ID and UX.
One chapter deals with memory, attention, and human capacities that influence interac­
tion. There is a chapter on understanding human emotion and how this affects interaction.
A central chapter on theories of cognition and action brings together the latest ideas on
embodied cognition, conceptual blending and how these impact the UX. Social interaction
is increasingly important to UX and ID and there is a chapter devoted to the key issues from
this area. Hearing, haptics (touch) and other ways of perceiving the world are considered
alongside the psychology of navigation in Chapter 25. This is fundamental knowledge that
the professional should seek to acquire. This part provides material aimed at the specialist
student or students studying HCI and ID in psychology or design schools.

Topics in HCI, UX and ID
The organization of the book does have a clear logic to it; however, I do not expect many
people will start at the beginning and read the book from cover to cover. Accordingly I
have provided a number of routes through the text for different people with different
needs (see below). The book also contains a comprehensive index so that people can
find their own ways in to areas of interest. I have also provided a list of intermediatelevel topics at the beginning of each Part. These are shown below in alphabetical order.
The topic number indicates which Part it appears in. Numbered topic lists appear in the
introduction to each Part.

Activities, contexts and technologies
Activity theory
Adaptive systems
Affective computing
Agent-based interaction
Auditory Interfaces
Blended spaces
Card sorting
Characteristics of people
Collaborative environments
Conceptual design
Context-aware computing
Cooperative working
Culture and identity
Design languages
Designing for pleasure
Developing questionnaires
Distributed cognition
Doing a PACT analysis
Embodied cognition
Embodied conversational agents
Emotion in people
Envisionment in practice
Evaluation in practice
Expert evaluation
Future Internet
Gestural interaction
Graphical user interfaces (GUIs)
Home environments
Human communication
Human error
Human information processing
Human memory
Ideas development
Information architecture
Information design
Information spaces
Interaction design case study
Interaction design principles
Interaction patterns
Interface design
Interviewing people
Metaphors and blends
Mixed reality
Mobile computing
Multimodal interaction

Topic 1.8
Topic 1.3
Topic 4.10
Topic 3.9
Topic 1.14
Topic 4.5
Topic 3.8
Topic 4.2
Topic 2.26
Topic 3.13
Topic 2.6
Topic 1.2
Topic 3.7
Topic 2.12
Topic 3.16
Topic 3.6
Topic 4.15
Topic 2.14
Topic 1.13
Topic 2.4
Topic 4.8
Topic 1.4
Topic 4.9
Topic 3.10
Topic 4.4
Topic 1.12
Topic 2.11
Topic 2.18
Topic 1.11
Topic 2.16
Topic 3.5
Topic 2.28
Topic 2.20
Topic 3.14
Topic 4.12
Topic 4.3
Topic 4.6
Topic 4.1
Topic 2.8
Topic 3.2
Topic 2.22
Topic 3.12
Topic 1.17
Topic 1.10
Topic 2.15
Topic 2.21
Topic 2.3
Topic 2.13
Topic 2.25
Topic 3.17
Topic 2.24

Sections 4.1-4.2
Sections 2.3-2.5
Section 23.5
Section 17.2
Section 5.4
Sections 22.4—22.5
Sections 17.1, 17.3-17.4
Section 21.3
Section 13.3
Section 18.3
Section 7.6
Section 2.2
Section 16.4
Section 9.4
Sections 19.2,19.5
Sections 16.1-16.3
Section 24.5
Section 9.5
Section 5.3
Section 7.4
Section 23.3
Sections 2.1, 2.6
Section 23.4
Sections 17.5
Sections 22.1-22.3
Section 5.2
Section 8.4
Sections 10.1, 10.4, 10.5
Section 5.1
Section 10.2
Section 15.5
Section 13.5
Section 12.3
Section 18.4
Section 24.2
Section 21.4
Section 23.1
Sections 21.1-21.2
Sections 7.7, 8.1, 9.1-9.2
Section 14.3
Section 12.5
Section 18.2
Chapter 6
Section 4.5
Section 9.5
Section 12.4
Section 7.3
Section 9.3
Section 13.2
Sections 19.1,19.3-19.4
Sections 13.1-13.2

Navigation case study
Navigation design for websites
Observation and ethnographic studies
Other forms of perception
Overview of designing interactive systems
Participative design
Participative evaluation
People in groups
Personas and scenarios
Scenario-based design
Service design
Situated action
Sketching and wireframes
Social media
Introduction to social psychology
Surface computing
Tangible user interfaces
Task analysis
The design process
Ubiquitous computing
Usability and acceptability
User experience (UX)
Visual perception
Wearable computing
Website design

Topic 4.17
Topic 3.15
Topic 3.3
Topic 2.7
Topic 4.16
Topic 1.1
Topic 2.1
Topic 2.17
Topic 4.13
Topic 1.6
Topic 4.14
Topic 2.5
Topic 2.10
Topic 2.2
Topic 1.7
Topic 1.15
Topic 4.7
Topic 2.9
Topic 3.4
Topic 4.11
Topic 2.29
Topic 2.27
Topic 2.19
Topic 1.5
Topic 3.11
Topic 1.9
Topic 1.16
Topic 4.15
Topic 2.23
Topic 3.18
Topic 3.1

Section 25.4
Sections 18.5, 19.5
Section 14.4
Section 7.8
Section 25.3
Chapter 1
Section 7.2
Section 10.3
Section 24.3
Section 3.2
Section 24.4
Section 7.5
Section 8.3
Section 7.1
Sections 3.3-3.4
Section 5.5
Section 23.2
Section 8.2
Sections 15.1-15.4
Section 24.1
Section 13.5
Section 13.4
Chapter 11
Section 3.1
Sections 18.1, 18.5
Sections 4.3^1.4
Chapter 5
Section 25.2
Section 12.6
Chapter 20
Sections 14.1-14.2, 14.5

There is a wide range of people involved in the design and development of interactive
systems in the twenty-first century. Software engineers are developing new applications
for their organizations. They redesign systems to take advantage of developments in
technologies and add on extra features to legacy systems. Software engineers working for
software companies develop new generic software products or new releases of existing
systems. Systems analysts and designers work with clients, end-users and other stakehold­
ers to develop solutions to business problems. Web designers are increasingly in demand
to organize and present content and new functionality for websites. People are develop­
ing applications for new media such as interactive television, ‘third-generation’ (3G)
mobile phones, personal digital assistants and other information appliances. Product
designers are increasingly finding themselves working with interactive features in their
products. Many other people with job titles such as User Experience Designers, Information
Architects and Interaction Designers are involved in this rapidly changing business. All
these people need education and training, and require ready access to proven methods
and techniques of design and evaluation and to the key theoretical concepts.


P reface

Just as the range of people involved in the development and deployment of inter­
active systems is increasing, so is the range of activities. The basic components of
design - establishing requirements and developing systems - are common across
all these types of interactive products and systems, but detailed activities vary. For
example, the analyst-designer working in an office environment would be likely to
use traditional requirements generation techniques such as interviewing, whereas the
developer of a new smartphone app might use focus groups and ‘future workshops’. A
website designer would make use of navigation maps, whereas an application devel­
oper might produce a prototype in a programming language such as Visual Basic to
show to potential users. An evaluation of a mobile phone might focus on aesthetics,
style and ‘teenage appeal’, whereas an evaluation of a shared diary system in a large
bank might concentrate on efficiency and time-saving and acceptance issues.
Contexts of interaction are increasingly diverse. Large organizations such as hospitals
are introducing smartphones and tablets for consultants and nurses. Universities are intro­
ducing purpose-built shared intranet systems to control development of course materials.
Oil-rigs have three-dimensional Virtual reality’ training programs and electricity com­
panies are using text messaging to record meter readings. A start-up software company
wants to introduce quality and usability control through its software development process
and a new media company is developing a Web-based service for its customers. Household
environments, on-line communities, mobile computing, offices and remote Virtual organi­
zations’ are just a few of the contexts for twenty-first-century human-computer interaction
design. Most importandy, we are seeing technologies bringing people into contact with
people. The design of on-line communities and other systems to support the social aspects
of life is a move away from the retrieval of information that characterized older systems.
Finally, technologies are changing. Software development is moving from top-heavy meth­
odologies based on object-oriented techniques with the Unified Modeling Language (UML)
dominant, to agile development methods. Websites often include Java programming and
have to interface with databases. Phones run under new operating systems such as Android
and new network protocols are needed for voice applications through mobile phones and
remote control of other devices such as heating controllers. Geographical positioning systems
and complete in-car navigational systems have to be seen alongside new concepts in digital
entertainment through interactive television and home information centres. Mobile phones
converge with digital cameras and MP3 music systems. Multitouch surfaces and gesture
recognition are poised to make significant changes to the way we interact with technologies.
So, how do educators and practitioners cross these diverse areas and combinations
of people, activities, contexts and technologies? We need to train software engineers to
know about and apply principles of usability, Web designers to produce creative designs
that are accessible to all, and systems analysts to be sympathetic to the situated nature of
work. We need product developers who design for the elderly and infirm, engineers who
understand people, their capacities and limitations, and creative people who understand
the constraints of software engineering. We need information architects, user experience
designers and service design professionals to understand the principles of HCI, accessibil­
ity and usability. Designing Interactive Systems aims to meet the educational and practical
needs of this diverse group by providing the variety of perspectives that is necessary.

How to use this book
HCI, UX and the design of interactive systems take place in a wide variety of contexts, by
individuals working alone or in design teams of various sizes. The systems or products to be
produced vary enormously in size and complexity and utilize a range of technologies. There

is no ‘one size fits all’ approach that can deal with this variety. In this book and its associated
website I provide a variety of perspectives to match the variety inherent in the design of
interactive systems. A professional interactive system designer will need to achieve a compe­
tence in all the methods and techniques described in this book and will need to understand
all the issues and theories that are raised. To achieve this level of competence would take
three years of study for an undergraduate student. But not everyone needs to achieve this
level, so I have organized the material to make different types of understanding available.
It is an ambitious task to write a complete guide to the design of interactive systems
when the area is still evolving. However, I have made an effort to mention all the currently
important issues and the further reading at the end of each chapter provides directions on
where to go next for more detailed coverage of specific issues. There is also a comprehen­
sive website with student notes, further exercises and tags (keywords) for each chapter
subsection to allow for easier searching for additional material.
Of course, the very nature of books is itself changing rapidly and this too is reflected
in this new edition. Using a phone running a suitable app, readers can instantly access
the Web material associated with each section and get the up-to-date detail directly
from the Web. There are also video links in the text so that readers can watch videos
related to their studies. So whether you are reading this on a Kindle or iPad or as a
printed book, the interactive experience of the text will be as engaging as any other.
The pedagogic style adopted by the text ensures that it meets the needs of students
and teachers alike. Boxes are used to highlight significant examples of the subject under
discussion and to point readers to interesting diversions. Forward and backward refer­
ences help to show how topics are linked. Case studies that the author has been involved
with have been included to illustrate the issues and to provide a rich source of examples
for students and teachers.
The book can be used in part or in total on a wide variety of courses, from special­
ist degrees in Human-Computer Interaction to a minor part of a degree in Software
Engineering to specialist modules on Design or Engineering degrees, Psychology,
Communication and Media degrees or other programmes where the design of interactive
systems and products is important. Most importantly, this book has been designed with its
accompanying website in mind. In the book are the things that I do not expect to change
over the next period (up until 2016). The structure should remain stable over this period
and the content will remain relevant. All the details that I expect to change are on the web­
site and this will be maintained to ensure it is up to date. Indeed readers are encouraged to
e-mail if they find better examples, broken links or out-of-date material. The accompany­
ing website (at should be considered part of the book.
I and my colleagues have been using this book for several years now and I meet and
talk to others who use the book at their universities. The material is highly accessible
and flexible. Chapters 1-4, for example, provide the basis of a 200-hour course for firstyears and Chapters 1-10 provide a 200-hour course for masters students. Chapters 2, 3,
4 and 10 provide a 16-hour course for on-line financial product developers. To explain
how the material can be used, I refer to a first- or second-year undergraduate course of
study as ‘level 2’ material, third-year as ‘level 3’ and fourth or masters as ‘level 4’.
Part I would form the basis of a level 2 course and indeed this is what I teach to our
second-year computing students. They study Processing as a prototyping language and
I include a number of ‘motivational’ lectures on current topics in addition to delivering
Topics 1.1 to 1.6 and 1.8 to 1.12 (Chapters 1-5) as a series of six two-hour lectures.
Part I material is also suitable for courses on interaction design and as introductory
material to a wide variety of level 3 modules. For example, with the materials from
Part II it would form a user-centred design module; with more material on psychology
from Part IV it would make a level 3 module on human-computer interaction. Chapter 3

and Part II can be used as a course on scenario-based design. Part IV is also suitable
at this level where the theoretical background for human-computer interaction is
required. In the past I have run an advanced module on navigation (Chapter 25) and
cognition (Chapter 23), applied to website design (Chapter 14) and mobile and ubiq­
uitous computing (Chapters 18 and 19). Part II provides a wealth of examples that
students can be pointed to that illustrate design issues or to learn specific design tech­
niques as they need them.
Our ‘rule of thumb’ for a typical course or module unit is 10-15 hours of student
time per week. This would be composed as follows and constitutes one ‘credit’. Over
the period of a year, full-time students study eight 15-credit modules or six 20-credit


Primary exposition of material (e.g. lecture)
Secondary presentation (e.g. seminar)


Unmoderated, informal student discussions


Practical exercises and activities


Research and further reading, based on the student notes and
further reading suggested
Revision and assessment


The following are examples of modules and courses that illustrate how the mate­
rial in this book could be used. These are just a few of the many variations that are

Material, chapter numbers

Level 2 Introduction to HCI (15 credits).
A basic-level course intended to
equip computing students with an
appreciation of HCI issues and a set of
practical skills.

Most of Chapters 1-5 (Topics 1.1-1.6 and
1.8-1.12) plus basic introduction to

Level 3 Interaction Design (15 credits).
A more advanced module aimed
at developing the issues concerned
with designing useful and engaging
interactions. Based around the
development of paper prototypes,
it encourages students to
focus on design issues rather
than programming issues.

Quickly revise material in Chapters 1-4,
but base the module around Chapters 7-10,
12 and 13 supplemented with chapters
from Part III according to the interest
of the lecturer and students. The focus
here is on scenarios and developing the
skills of envisionment, prototyping and
the evaluation of ideas. A critical study of
Chapter 6 case study is useful.

Level 3 User-centred Design (15 credits).
A module focusing on industrial-strength, This can be based on Chapter 3 using a formal
human-centred design process. Fits nicely scenario-based design as the design method.
alongside Interaction Design.
The conceptual and physical design described
in Chapter 9, based on object-action analysis
would supplement this, along with task analysis
methods (Chapter 11) and further evaluations
(Chapter 10).

C o u rs e /m o d u le

M a te ria l, c h a p te r n u m b e rs

Level 4 Advanced Interactive
Systems Design Concepts
(20 credits)

A masters-level module that looks at advanced
and modern interfaces such as wearable and
tangible computing. Look at experience design
in detail (Chapter 5), multimodal interaction
(Chapter 13), theories of action (Chapter 23),
perception and navigation (Chapter 25). Apply
to issues of collaborative environments and
gestural interaction (Chapter 16) and blended
spaces (Chapter 18).

Level 2 Web Design (15 credits).

Part I material supplemented with Chapters
14 and 15. Include evaluation (Chapter 10)
and visual interface design (Chapter 12)

Level 3 or 4 Module on Psychological
Foundations of Human-Computer
Interaction (20 credits).

In-depth coverage of Part IV materials.
Examples from Part III with some introductory
material from Part I.

Other resources
The text highlights other important resources where appropriate. Here are some pointers
to a few general resources. The Usability Professional Association (UPA) is a good place
for interested people to look for examples of good practice and links to other resources: The American Institute of Graphic Arts (AIGA,
is increasingly involved with interaction and information design. The Association of
Computing Machinery (ACM, has an active special interest group in
computer-human interaction (SIGCHI) and the British Computer Society also has an
excellent group for both academics and professionals ( . Both of
these have extensive resource libraries and organize many relevant conferences. There
are many good websites devoted to aspects of usability, human-computer interaction
and interaction design that can be found by following links from the sources on the
companion website at Finally, there are two inter­
national standards that deal with usability. They are ISO 9241-11 and 13407. The
European resource centre, ‘usability net’, has details at

The author
David Benyon is Professor of Human-Computer Systems at Edinburgh Napier University.
He began his career as a systems analyst working for a number of ‘software houses’ and
industrial companies. After several years he moved into academia where he developed
a more formal understanding of issues of HCI. The first US conference on computerhuman interaction took place in the same year that David began an MSc in Computing
and Psychology at Warwick University and in 1984 he published his first paper on the
subject. Since then he has continued to publish and now has over 150 published papers
and 12 books. He obtained his PhD in Intelligent User Interfaces in 1994 when he also
co-authored one of the first HCI textbooks, Human-Computer Interaction (by Preece,
Rogers, Sharp, Benyon, Holland and Carey, published by Addison-Wesley) and Usability
Now! (1993). He continues to take an active part in the HCI and ID communities, organ­
izing and presenting at conferences including CHI (Computer Human Interaction),

DIS (Designing Interactive Systems), Interact conferences and Interactions (British
Computer Society).
During his career David has worked on twenty European-funded research and devel­
opment and UK-funded research projects and ten knowledge transfer projects. He has
supervised twenty-six PhD students, examined forty-three and undertaken a number
of consultancy projects. This wide and extensive experience of all manner of HCI, ID
and UX puts David in a unique position within the world of interactive systems design.
All this experience and knowledge has fed into this book. In the Persona project David
worked with Kristina Hook from the Swedish Institute of Computer Science on ideas
of navigation of information spaces and on ‘social navigation’. He worked with Bang &
Olufsen of Denmark on concepts for a Home Information Centre (HIC) and with NCR,
UK on personalization of interfaces to self-service machines. He worked with the
University of Dundee and others on technologies for older people, with partners across
Europe on projects concerned with ideas of presence and with a large consortium of
Scottish universities on interacting with wireless sensor networks. He spent four years
exploring concepts of ‘Companions’ - advanced personalized multimodal interfaces to
the Internet - with Telefonica, France Telecom and others in a large integrated research
project and working with a number of Indian Institutes of Technology on gesture-based
interaction and multitouch displays. Most recently he has been working on applications
of multitouch surface computing and augmented reality for tourism applications.

This book has been developing for over seven years and in that time many friends
and colleagues have helped with ideas, comments and evaluations of materials. Draft
materials have been used with students and I would like to acknowledge their help in
producing the finished text. Methods and techniques have been developed and used on
a variety of research and development projects and I would like to thank all the students
and researchers who helped in this respect. In particular all the people who worked on
the European FLEX project helped to produce the case study in Chapter 6 and many
of the examples used in Part II. These included Tom Cunningham, Lara Russell, Lynne
Baillie, Jon Sykes, Stephan Crisp and Peter Barclay. The researchers on Companions, Oli
Mival, Brian O’Keefe, Jay Bradley and Nena Roa-Seiler, deserve acknowledgements for
their contributions. Other past and present students who have contributed to the ideas
and examples in this book include Bettina Wilmes, Jesmond Worthington, Shaleph
O’Neil, Liisa Dawson, Ross Philip, Jamie Sands, Manual Imaz, Martin Graham, Mike
Jackson, Rod McCall, Martin Clark, Sabine Gordzielik, Matthew Leach, Chris Riley,
Philip Hunt and David Tucker. Thanks also to Richard Nesnass, Aurelien Ammeloot and
Serkan Ayan.
I would like to thank all my colleagues at Edinburgh Napier University and those who
have moved on. In particular Catriona Macaulay was involved in many of the early dis­
cussions and contributed much through her innovative teaching and curriculum devel­
opment. Michael Smyth, Tom McEwan, Sandra Cairncross, Alison Crerar, Alison Varey,
Richard Hetherington, Ian Smith, Iain McGregor, Malcolm Rutter, Shaun Lawson,
Gregory Leplatre, Tom Flint, Emilia Sobolewska and Ingi Helgason have all contributed
through discussions, criticisms and chance remarks. The contribution of other members
of the School of Computing is also acknowledged.
David Benyon
Edinburgh Napier University, Edinburgh


Publisher's ackn o w led g em en ts
We are grateful to the following for permission to
reproduce copyright material:

Figure 3.2 after The rich picture: a tool for reasoning
about work context, Interactions, 5(2), pp. 21-30,
Figure 1 and Figure 2 (Monk, A. and Howard, S. 1998)
© 1998 ACM, Inc., reprinted by permission, h ttp ://; Figure 3.3
after John M. Carroll, Making Use: Scenario-based
Design of Human-Computer Interactions Figure 3.2,
p. 69 © 2000 Massachusetts Institute of Technology,
by permission of the MIT Press; Figure 4.1 after
Individual differences and inclusive design, in
Stephanidis, C. (ed.), Interfaces for All: Concepts,
Methods and Tools, Lawrence Erlbaum Associates
(Benyon, D. R. et al 2001), copyright 2000 by Taylor &
Francis Group LLC - Books, reproduced with permis­
sion of Taylor & Francis Group LLC - Books in the
format Textbook via the Copyright Clearance Center,
Inc; Figure 4.5 after User-Centered System Design:
New Perspectives on Human-Computer Interaction,
Lawrence Erlbaum Associates (Norman, D.A. and
Draper, S. (eds) 1986) reproduced with permission
of Taylor & Francis Group LLC - Books; permission
conveyed through Copyright Clearance Center, Inc;
Figure 4.7 after Norman, Donald A., The Invisible
Computer: Why Good Products Can Fail, the Personal
Computer Is So Complex, and Information Appliances
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Press; Figure 5.6 from The Customer Journey
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licensed under the Creative Commons AttributionShareAlike 3.0 Unported Licence. To view a copy
of this license, visit
licenses/by-sa/3.0/; Figure 6.9 adapted from The
Scotsman, August 1998, Scotsman Publications Ltd;
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org/im ages/encyclopedia/card_sorting/groups_
chart_26_participants.jpg, with permission from
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David Benyon; Figure 8.8 (top) from Wireframe
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gif, SmartDraw; Figure 8.8 (bottom) from Wireframe
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of SPIE, 2351, p. 282 (Milgram, P., Takemura, H.,
Utsumi, A. and Kishno, F. 1995), with permis­
sion from SPIE; Figure 14.2 from The Elements of
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(Garrett, J.J. 2003) © 2003 Jesse James Garrett,
reproduced by permission of Pearson Education,
Inc. publishing as New Riders Publishing, all rights
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Publisher's acknowledgements

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Publisher's acknowledgements

Thesaurus™ (powered by Thimkmap®) © 2004
Plumb Design, Inc., all rights reserved; Screenshot
13.3 from
2010/05/icon-quake26-hf.jpg, used with permission
of Dr. Bruce H. Thomas, Wearable Computer Lab,
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left) from adidas shop United Kingdom, http://w w w ., ‘adidas’, ‘3-Bars’, ‘3-Stripes mark’,
‘The Globe logo’, ‘The Trefoil Logo’, ‘ADICOLOR’,
‘SLVR’, and ‘SUPERNOVA’ are trade marks of the adi­
das Group, used with permission; Screenshot
14.1 (top right) from edutopia © 2009, The George
Lucas Educational Foundation (GLEF), www. All Rights Reserved; Screenshot 14.1
(bottom) from WHITEvoid Portfolio, h ttp ://, WHITEvoid Interactive art & design,
Kastanienallee 89, D-10435 Berlin; Screenshot 14.5
from Yahoo! UK and Ireland TV - Listings, Yahoo!;
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Publisher's acknowledgements

Proceedings of the Twenty-sixth Annual SIGCHI confer­
ence on Human Factors in Computing Systems, 5-10
April, Florence, Italy © 2008 ACM, Inc. Reprinted by
permission, http://doi.acm .org/10.1145/1357054.
1357237, the research and development behind the
Magitti system was sponsored by Dai Nippon Printing
Co. Ltd. ‘Media Technology Research Center’ and
‘Corporate R & D Division’; Screenshot 19.8 from
Escape: a target selection technique using visuallycued gestures, Proceedings of the Twenty-sixth Annual
SIGCHI Conference on Human Factors in Computing
Systems, 5-10 April (Yatani, K., Patridge, K., Bern, M.,
Newman, M.W. 2008) © 2009 ACM, Inc. Reprinted
by permission,
1357104; Screenshot 21.11 from Jon Kerridge;
Screenshot 22.5 from EU Funded Project (IST-220139192) EMMA Project; Screenshot 24.10 from Stress
OutSourced, MIT Media Lab, Tangible Media Group;
Screenshot 25.24d from Pearson Education.

Table 9.1 from Marshall Lapham, Understanding
Media: The Extensions of Man, 1 Table from introduc­
tion © 1994 Massachusetts Institute of Technology,
by permission of The MIT Press; Table 10.2 adapted
from A survey of user-centred design practice,
Proceedings of SIGCHI conference on Human factors
in computing systems: Changing our world, chang­
ing ourselves, pp. 471-78, Table 3 (Vredenburg, K.,
Mao, J.-Y., Smith, P.W. and Carey, T. 2002) ©
2002 ACM, Inc. Reprinted by permission, h ttp ://; Table 10.3
terms and definitions taken from ISO 9241-11:1998
Ergonomic requirements for office work with visual
display terminals (VDTs), extract of Table B2, repro­
duced with the permission of the International
Organization for Standardization, ISO, this standard
can be obtained from any ISO member and from
the website of the ISO Central Secretariat at the
following address:, copyright remains
with the ISO; Table 12.1 after Marcus, Aaron,
Graphic Design for Electronic Documents and User
Interfaces, 1st, © 1991. Printed and Electronically
reproduced by permission of Pearson Education,
Inc., Upper Saddle River, New Jersey; Table 13.1
Apple Inc; Table 17.1 from Stereotypes and user
modelling, in Kobsa, A. and Wahlster, W. eds, User
Models in Dialog Systems, Figure 4, p. 41 (Rich, E.
1989), Springer-Verlag and Elaine Rich; Table 21.2
from Wickens, Christoper D.; Hollands, Justin G.,

Engineering Psychology and Human Performance, 3rd,
© 2000. Printed and Electronically reproduced by
permission of Pearson Education, Inc., Upper Saddle
River, New Jersey; Table 22.1 adapted from Picard,
Rosalind W., Affective Computing Table 1.1 © 1997
Massachusetts Institute of Technology, by permis­
sion of The MIT Press; Table 22.2 reprinted from
International Journal of Human-Computer Studies,
59(1-2), McNeese, M.D., New visions of humancomputer interaction: making affect compute,
pp. 33-53, Copyright 2003, with permission from
Elsevier; Tables 24.1, 24.2 from Distance matters,
Human-Computer Interaction, 15(2), p. 149, p. 160
(Olson, G.M. and Olson, J.S. 2000), reprinted by
permission of the publisher (Taylor & Francis Ltd,

Box 1.1 Copyright © 1993 by Donald Norman, Things
That Make Us Smart: Defending Human Attributes
in the Age of the Machine, Reprinted by permis­
sion of Perseus Books, an imprint of the Perseus
Books Group; Box 4.1 from Principles of Universal
Design, North Carolina State University (Connell,
B.R., Jones, M., Mace, R., Mueller, J., Mullick, A.,
Ostroff, E., Sandford, J., Steinfield, E., Story, M. and
Vanderheiden,G. 1977) ©Centre forUniversal Design,
College of Design, North Carolina State University;
Extract on pages 96-97 from Digital ground: fix­
ity, flow and engagement with context, Archis, 5
(special ‘flow’ issue, Oct/Nov) (McCullough, M.
2002), with permission from the author; Box 5.1
adapted from on-line interview, http://infodesign., with permission from
William G. Gaver; Box 7.4 from Grounding blue-sky
research: how can ethnography help?, Interactions,
4(3), pp. 58-63 (Rogers, Y. and Bellotti, V. 1997),
© 1997 ACM, Inc., reprinted by permission, h ttp ://; Extract on
page 278 Apple Inc; Extract on page 279 Apple
Inc; Box 12.3 Apple Inc; Box 14.4 from Strategies
for Categorizing Categories,, 7 May
2003, User Interface Engineering; Extract on page
332 from email from RA to team; Box 16.3 from
Council bans emails to get staff to talk, The Guardian,
10 July 2002 (Ward, D.), Copyright Guardian News &
Media Ltd 2002; Extracts on page 441, pages 442-3
from Activity-based serendipitous recommendations
with the Magitti mobile leisure guide, Proceedings
of Twenty-sixth Annual SIGCHI conference on Human

Publisher's acknowledgements

Factors in Computing Systems, 5-10 April, Florence,
Italy © 2008 ACM, Inc. Reprinted by permission,, the
research and development behind the Magitti sys­
tem was sponsored by Dai Nippon Printing Co. Ltd.
‘Media Technology Research Center’ and ‘Corporate
R & D Division’; Extract on pages 505-6 reprinted
from International Journal of Human-Computer
Studies, 59(1-2), Hollnagel, E. Is effective comput­
ing an oxymoron?, pp. 65-70, Copyright 2003, with
permission from Elsevier.

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4 11 h %
31 |f £* % h

Essentials of designing
interactive systems
1 Designing interactive system s: a fusion of skills 5
2 PACT: a framework for designing interactive systems 25
3 The p rocess of hum an-centred interactive system s
design 48
4 Usability 76
5 Experience design 93

6 The Hom e Information Centre (HIC): a ca se study in
designing interactive system s



Part I • Essentials of designing interactive systems

Introduction to Part I
Our goal is to design interactive systems that are enjoyable to use, that do useful things
and that enhance the lives of the people who use them. We want our interactive systems
to be accessible, usable and engaging. In order to achieve this we believe that the design
of such systems should be human-centred. That is, designers need to put people rather
than technology at the centre of their design process. Unfortunately, the design of inter­
active systems and products in the past has not always had a good record of considering
the people who use them. Many systems have been designed by programmers who use
computers every working day. Many designers are young males. Many designers have
been playing computer games for years. This means that they forget just how difficult
and obscure some of their designs can be to people who have not had these experiences.
In the days of the Web, issues of usability are critical to e-commerce. Before the imme­
diacy of e-commerce, usability problems were discovered only after purchase. If you
bought a nice-looking smartphone and brought it home only to find it was difficult to
use, you could not take it back! The shop would say that it delivers its functions; all you
had to do was to learn how to operate it properly. On the Web, customers look at usabil­
ity first. If the system is hard to use, or if they do not understand it, they will go some­
where else to make their purchase. People are learning that systems do not have to be
hard to use and are becoming more critical about the design of other products too.
This first part of the book provides a guide to the essence of the human-centred design
of interactive systems. Chapter 1 focuses on the main elements of interactive systems
design. It considers the nature of design, the features of interactive systems and what it
means to be human-centred. The chapter provides a brief history of human-computer
interaction and interaction design and a glimpse of the future, before focusing on why
designing interactive systems is important. Chapter 2 introduces the key components
of interaction - people, activities, contexts and technologies (PACT). This proves to be
an insightful construct not just for understanding the breadth of interaction design, but
also for doing design. The chapter describes and illustrates a first design method: PACT
Alongside this view we need to consider the products we are designing: what they will
do, how they will do it and what information content they will manipulate. In Chapter 3
we look at the processes involved in designing interactive systems. We see why the eval­
uation of ideas is central to the process if we are going to be focused on people: 'being
human-centred'. The requirements for products, early designs and prototypes of systems
all need to be evaluated to ensure that they meet the needs of the people who will use
them. But people will make use of technologies in many different contexts, to under­
take different activities. The chapter introduces key abstractions for helping designers
in their tasks: personas and scenarios. We give examples of personas and offer practical
advice on how they can be developed and used. The chapter goes on to provide a whole
scenario-based design method, providing advanced treatment of this important idea.
In Chapter 4 we look at principles of design: how to ensure systems are accessible, usa­
ble and acceptable. As interactive systems become increasingly embedded in society,
they stop being a luxury. Accessibility is about ensuring that the benefits of interaction
design are available to all. Another key concept in interaction design that has long been
the central focus of human-computer interaction (HCI) is usability. Chapter 4 provides a

Introduction to Part I

detailed consideration of usability and acceptability. Finally the chapter provides some
high-level design guidelines that will help designers ensure that designs are accessible
and usable.
When people use the devices we have designed, what do they feel? Do they have a sense
of satisfaction, enjoyment and engagement? Chapter 5 looks at these issues and at aes­
thetics and designing for pleasure. Once again this serves to illustrate the wide scope of
interactive systems design. The chapter also includes some discussion of service design
as increasingly designers need to design services as well as products. The final chapter
is an extended case study of a design, showing how and why decisions were made and
illustrating many of the ideas developed in the first five chapters.
After studying this part you should understand the essential features of designing inter­
active systems. In particular:

What interactive systems design is
Who is involved
What is involved
How to develop systems that are human-centred
Principles of interactive systems design to ensure systems are usable and engaging.

Case studies
The concepts and ideas are illustrated throughout through a number of case studies.
Chapter 1 introduces several modern devices that have made a big impact on the world
of interaction design. Chapter 2 uses the development of a swipe-card system to illus­
trate the PACT method. Chapter 3 introduces the MP3 player case study. This involves
the development of an MP3 function for the Home Information Centre (H 1C) which is
itself the focus of the extended case study in Chapter 6. Both the MP3 and the overall
HIC case studies are also used in Part II.

Teaching and learning
With some supplementary material showing examples, following up on the Web links
and further reading and doing some assessed exercises, the material in this part would
make an ideal introductory course on human-computer interaction or interaction
design. The list of topics covered in this part is shown below, each of which could take
10-15 hours of study to reach a good general level of understanding, or 3-5 hours for a
basic appreciation of the issues. Of course, each topic could be the subject of extensive
and in-depth study.


Overview of designing interactive systems
Characteristics of people
Activities, contexts and technologies
Doing a PACT analysis
The design process
Personas and scenarios
Scenario-based design
Usability and acceptability
Interaction design principles

Chapter 1
Section 2.2
Sections 2.3-2.5
Sections 2.1,2.6
Section 3.1
Section 3.2
Sections 33-3.4
Sections 4.1-4.2
Sections 43-4.4
Section 4.5



Part I • Essentials of designing interactive systems

Topic 1.11 Experience
Topic 1.12 Engagement
Topic 1.13 Designing for pleasure
Topic 1.14
Topic 1.15
Topic 1.16
Topic 1.17

Service design
User experience (UX)
Interaction design case study



Section 5.5
Chapter 5
Chapter 6

Chapter 1
D esigning interactive system s:
a fusion of skills



1.1 The variety o f interactive
systems 6

Designing interactive systems is concerned with developing highquality interactive systems, products and services that fit with people
and their ways of living. Computing and communication devices are
embedded in all sorts of everyday devices such as washing machines
and televisions, ticket machines and jewellery. No self-respecting
exhibition, museum or library is without its interactive component.
We carry and wear technologies that are far more powerful than
the computers of just a few years ago. There are websites, on-line
communities, 'apps' for mobile phones and tablets and all manner of
other interactive devices and services that need developing. Interactive
systems design is about all this.

1.2 The concerns of interactive
systems design 9
1.3 Being digital 13
1.4 The skills of the interactive
systems designer 18
1.5 W hy being hum an-centred is
im portant 20
Sum m ary and key points 22
Exercises 22
Further reading 22
Web links 23

In this chapter we explore the width and breadth of designing
interactive systems. After studying this chapter you should be able to:

Com m ents on challenges 23

• Understand the concepts underlying the design of interactive
• Understand why being human-centred is important in design
• Understand the historical background to the subject
• Understand the skills and knowledge that the designer of interactive
systems needs to draw upon.


Part I • Essentials of designing interactive systems


........... ■.............................................. ....................-................................. - .. ................. ^


The variety of interactive system s

Designing interactive systems is concerned with many different types of product. It
is about designing software systems that w ill run on a computer at work. It is about
designing websites, games, interactive products such as MP3 players, digital cameras
and applications for tablet PCs (personal computers). It is about designing whole envi­
ronments in which phones, tablets, laptop computers, digital projectors and other
devices and services communicate with one another and through which people interact
with one another. It is about designing interactive systems, products and services for the
home, for work or to support communities.
Here are some examples of recent interactive products and systems.

Example 1: The iPhone
In 2007 Apple Inc. changed the face of mobile technologies when they introduced the iPhone
(Figure 1.1). The iPhone had a carefully crafted, purpose-designed interface to make use of
the finger as the input device. It had a revolutionary touch-sensitive screen that allowed for
multi-touch input. This facilitated new interaction techniques such as pinching an image and
drawing it in to make it smaller, or pinching and moving the fingers out to make an image
larger. Many mobile devices and larger screen systems have now adopted this technology,
but the iPhone started it. The iPhone also included sensors that could register how the phone
was being held and whether it was vertical, horizontal or sloping. This allows for other novel
interaction methods. For example, the display would automatically adjust from portrait style
to landscape. In 2008 the 'app store' was launched, turning the iPhone into an open platform
for developers to design and produce their own software. Combined with the iTunes delivery
service, this turned the iPhone into a versatile, multimedia device with hundreds of thousands
of applications, from sophisticated games to trivial pieces of entertainment to useful informa­
tion applications. This created new experiences and new services for a new set of custom­
ers that has now spread to many other devices running the Android operating system (from
Google) or Windows (from Microsoft). The most recent iPhone has introduced a speech rec­
ognition system called Siri that allows people to call or text their friends, enter appointments
in a calendar or search the Web just by speaking into the phone.

Figure 1.1 iPhone
(Source: Hannah Gal/Science Photo Library)

Chapter 1 • Designing interactive systems: a fusion of skills

Example 2: The Nintendo Wii
Also in 2007 Nintendo introduced the Wii (Figure 1.2). The Wii was a revolutionary new
games concept that used infra-red sensors attached to a TV or other display device to track
a wand that transmitted infra-red signals. The new system could, therefore, register different
gestures such as a 'bowling' action, a 'tennis shot' action or a host of other movements. The
notion of computer games changed radically, from a young person shooting at imaginary
monsters, or driving imaginary cars, to a family-wide entertainment. When the Wii Fit was
introduced it appealed to a new audience of people wanting to keep fit at home. In 2011
Microsoft introduced their Kinnect system that combined infra-red detection and cameras
so that users could interact with software using gestures with no need for a wand. Originally
aimed at people playing games on the Xbox games machine, the Kinnect was quickly adapted
to work with any software that could make use of its application program interface (API).

Figure 1.2 Wii Fit
(Source: Keith Morris/Alamy Images)

Example 3: Virtual worlds
Second Life (Figure 1.3) is a huge on-line community populated by animated virtual people
(called avatars). It consists of thousands of simulated buildings, parks, seasides, factories, uni­
versities and everything else one could find in the real world (and much else besides). People
create avatars to represent themselves in this virtual world. They can determine their size,
shape, gender and what they want to wear. They are controlled by their creators using the
Internet, interacting with other avatars, and visiting virtual places. Other examples of virtual

Artificial life
Artificial life (often abbreviated to 'Alife') is a branch of artificial intelligence (Al), the
discipline that looks at whether intelligent software systems can be built and at the
nature of intelligence itself. The tradition in Al has been to represent knowledge and
behaviours through rules and rigid structures. Alife tries instead to represent higherlevel features of the things in an environment, such as the goals that a creature has
and the needs that it must satisfy. The actual behaviour of the artificial creatures is then
more unpredictable and evolves in the environment. Increasingly, characters in com­
puter games are using Alife techniques.



Part I • Essentials of designing interactive systems

Figure 1.3 Second Life

Figure 1.4 Sony Vita

(Source:, Linden Lab)

(Source: Kiyoshi Ota/Getty Images)

worlds include highly popular games such as World of Warcraft and the Sony Home environ­
ment that is played on their Playstation platform and Vita handheld device (Figure 1.4). Many
of these games include playing on-line with others, a key part of the social side of designing
interactive systems.

Example 4: i Robo-Q domestic toy robot
The i Robo-Q domestic toy robot is an example of the new children's toys that are increasingly
available (Figure 1.5). Toys are using all manner of new technologies to enhance the experi­
ences of children at play. They use robotics, voice input and output, and a variety of sensors to
provide novel and engaging interactions.

Example 5: Facebook
Facebook (Figure 1.6) is a highly popular website that allows people to keep in contact with their
friends. Known as social networking sites, there are m any sim ilar systems around. Facebook is
the most popular with nearly 1 billion users w orldw ide. Facebook is increasingly becoming
an im portant platform for a w ide variety of activities and it allows people to add applications
(apps) in a sim ilar w ay to the A pple and Android platforms. People can store and share digital

Figure 1.5 i Robo-Q domestic toy robot

Figure 1.6 Facebook

(Source: Getty Images/ChinaFotoPress)

(Source: Facebook, Inc.)

Chapter 1 • Designing interactive systems: a fusion of skills

photos, write notes to each other and get regular updates about what their friends are doing.
Facebook will probably have its own mobile handset soon as it moves from being just a web­
site into being an important platform for the delivery of all sorts of interactive systems.

These five examples of interactive systems capture many of the features that the inter­
active systems designer has to work with. The designer of interactive systems needs to
understand the possibilities that exist for new forms of interaction, with fixed devices
or mobiles, for people on their own or for connecting people to each other through text
messages or through animation and video. It is a fascinating area to work in.

Challenge 1.1
Find five interactive products or systems that you use - perhaps a coffee machine, a
cellular phone, a fairground ride, a TV remote control, a computer game and a website.
Write down what it is that you like about each of them and what it is that you do not
like. Think about the whole experience and not just the functions. Think about the
content that each provides: Is it what you want? Is it fun to use?
If possible, find a friend or colleague to discuss the issues. Criticism and design are social
activities that are best done with others. What do you agree on? What do you disagree
on? Why?

1.2 The concerns of interactive system s design
The design of interactive systems covers a very wide range of activities. Sometimes
designers will be working on both the hardware and the software for a system, in which
case the term ‘product design’ seems to be most appropriate to describe what they are
doing. Sometimes the designer will be producing a piece of software to run on a com­
puter, on a programmable device or over the Internet. In these cases the terms ‘system
design’ and ‘service design’seem more appropriate. We switch between these expressions
as appropriate. However, the key concerns of the designer of interactive systems are:
• Design. What is design and how should you do it?
• Technologies. These are the interactive systems, products, devices and components
• People who will use the systems and whose lives would we like to make better
through our designs?
• Activities and contexts. What do people want to do? What are the contexts within
which those activities take place?

What is design? It's where you stand with a foot in two worlds - the world of technology and
the world of people and human purposes - and you try to bring the two together.
Mitch Kapor in Winograd (1996), p. 1

The term ‘design’ refers both to the creative process of specifying something new and to
the representations that are produced during the process. So, for example, to design a
website a designer will produce and evaluate various designs, such as a design of the page



Part I • Essentials of designing interactive systems

layout, a design of the colour scheme, a design for the graphics and a design of the overall
structure. In a different field of design, an architect produces sketches and outlines and
discusses these with the client before formalizing a design in the form of a blueprint.
Design is rarely a straightforward process and typically involves much iteration and
exploration of both requirements (what the system is meant to do and the qualities it
should have) and design solutions. There are many definitions of ‘design’. Most defini­
tions recognize that both problem and solution need to evolve during the design process;
rarely can you completely specify something before some design work has been done.
One thing that is useful is to distinguish the amount of formality associated with a
• At one end of a spectrum is engineering design (such as the design of a bridge, a car
or a building) where scientific principles and technical specifications are employed
to produce formal models before construction starts.
• At the other end of this spectrum is creative or artistic design where innovation,
imagination and conceptual ideas are the key ingredients.
• Somewhere in the middle lies ‘design as craft’ which draws upon both engineering
and creative approaches.
Most design involves aspects of all of these. A fashion designer needs to know about
people and fabrics, an interior designer also needs to know about paints, lighting and
so on, and a jewellery designer needs to know about precious stones and the properties
of metals such as gold and silver. The famous design commentator Donald Schon has
described design as a ‘conversation with materials’, by which he means that in any type
of design, designers must understand the nature of the materials that they are working
with. Design works with, and shapes, a medium; in our case this medium consists of
interactive systems. Others emphasize that design is a conscious, social activity and that
much design is often undertaken in a design team.

People and technologies
Interactive system is the term we use to describe the technologies that interactive system
designers work with. This term is intended to cover components, devices, products and
software systems that are primarily concerned with processing information. Interactive
systems are things that deal with the transmission, display, storage or transformation
of information that people can perceive. They are devices and systems that respond
dynamically to people’s actions.
This definition is intended to exclude things such as tables, chairs and doors (since
they do not process information) but to include things such as:
• Mobile phones (since they transmit, store and transform information)
• Websites (since they store and display information and respond to people’s actions)
• Computer game controllers.
Increasingly, interactive components are being included in all manner of other products
(such as clothes, buildings and cameras).
A fundamental challenge for interactive systems designers is to deal with the fact
that people and interactive systems are different (see Box 1.1). Of course we take the
people-centred view, but many designers still take the machine-centred view because
it is quicker and easier for them, though not for the person who finishes up using the
product. Another difference between people and machines is that we speak differ­
ent languages. People express their desires and feelings in terms of what they want to
do or how they would like things to be (their goals). Machines need to be given strict

Chapter 1 • Designing interactive systems: a fusion of skills


Machine- and people-centred views

People are

Machines are








Attentive to change

Insensitive to change

Able to make flexible
decisions based on

Constrained to make
consistent decisions


Source: Adapted from Norman (1993), p. 224

The interface
The interface to an interactive system, also called the user interface (UI), is all those parts of
the system with which people come into contact, physically, perceptually and conceptually:
• Physically we might interact with a device by pressing buttons or moving levers and
the interactive device might respond by providing feedback through the pressure of
the button or lever.
• Perceptually the device displays things on a screen which we can see, or makes noises
which we can hear.
• Conceptually we interact with a device by trying to work out what it does and what
we should be doing. The device provides messages and other displays which are
designed to help us do this.
The interface needs to provide some mechanisms so that people can provide instruc­
tions and enter data into the system: ‘input’. It also needs to provide some mechanisms
for the system to tell people what is happening by providing feedback and mechanisms
for displaying the content: ‘output’. This content might be in the form of information,
pictures, movies, animations and so on. Figure 1.7 shows a variety of interfaces.

Challenge 1.2
Look at the pictures in Figure 1.7. What does the interface to (a) the remote control,
(b) the microwave, (c) the palmtop computer or (d) the Xbox controller consist of?

Designing interactive systems is not just a question of designing interfaces, however. The
whole human-computer interaction needs to be considered, as does the human-human
interaction that is often enabled through the systems. Increasingly, interactive systems con­
sist of many interconnected devices, some worn by people, some embedded in the fabric of
buddings, some carried. Interactive systems designers are concerned with connecting people
through devices and systems; they need to consider the whole environment they are creating.

-> Chapter 2 discusses input
and output devices in more


Part I • Essentials of designing interactive systems

Figure 1.7 Various user interfaces: remote control; microwave; palmtop; and Xbox controller
(Source: (a) Fujitsu: (b) © D. Hurst/Alamy Images; (c) Gareth Boden/Pearson Education Ltd. (d) Microsoft Limited)

Being human-centred
Interactive systems design is ultimately about creating interactive experiences for
people. Being human-centred is about putting people first; it is about designing interac­
tive systems to support people and for people to enjoy. Being human-centred is about:

Thinking about what people want to do rather than what the technology can do
Designing new ways to connect people with people
Involving people in the design process
Designing for diversity.

The evolving nature of interactive systems design
The primary discipline contributing to being human-centred in design is humancomputer interaction (HCI). HCI arose during the early 1980s, evolving into a subject
'concerned with the design, evaluation, and implementation of interactive computing
systems for human use and with the study of major phenomena surrounding them'
(ACM SIGCHI, 1992,
■U N

Chapter 1 • Designing interactive systems: a fusion of skills

HCI drew on cognitive psychology for its theoretical base and on software engineer­
ing for its design approach. During the 1990s the closely related area of Computer
Supported Cooperative Work (CSCW) focused on technology support for coopera­
tive activities and brought with it another theoretical base that included sociology and
anthropological methods. At the same time, designers in many different fields found
that they had to deal with interactive products and components, and in 1989 the first
computer-related design course was established at the Royal College of Art in London.
In America the designers at Apple were putting their ideas together in a book called
The Art of Human-Computer Interface Design (Laurel, 1990a) and a meeting at Stanford
University in 1992 resulted in the book Bringing Design to Software (Winograd, 1996). By
the mid-2000s interaction design was firmly established as a discipline in its own right
with the first textbooks on interaction design coming out (including the first edition
of this book) and leading designers contributing their own insights. All this - coupled
with the phenomenal changes in computing and communication technologies dur­
ing the same period - has brought us to where we are today: a dynamic mix of ideas,
approaches and philosophies applied to the design of interactive systems and products.

This book is about human-centred interactive systems design. It is about hum ancomputer interaction (HCI) and interaction design in the twenty-first century.

1.3 Being digital
In 1995 Nicholas Negroponte, head of the Massachusetts Institute of Technology’s
‘Media Lab’, wrote a book called Being Digital in which he explored the significance of
an era in which we change atoms for bits. We live in a digital age, when all manner
of devices represent things using binary digits (bits). The significance of being digital
is that bits are transformable, transmittable and storable using digital technologies.
Consider the following scenario.
In the morning you get woken up by a digital alarm clock which automatically turns on
the radio. To change the radio channel you might press a button that searches for a strong
signal. You pick up your mobile, cellular phone and check for messages. You might go
to your computer and download a personalized newspaper into a tablet device. As you
leave the house you set the security alarm. In the car you adjust the heating, use the radio
and attend to the various warning and information symbols that detect whether doors are
open, or seat belts are buckled. Arriving at the station, you scan your season ticket through
the car parking machine, get a train ticket from the ticket machine and get money from
an automated teller machine (ATM). On the train you read the newspaper on your tablet,
scrolling through text using your finger. Arriving at your office, you log on to the computer
network, check e-mail, use various computer packages, browse the Web and perhaps lis­
ten to an Internet radio station broadcasting from another country. You have a video link
with colleagues in other cities and perhaps work together on a shared document. During
the day you use a coffee machine, make calls on the cellphone, check names and num­
bers in the address book, download a new ringing tone, photograph a beautiful plant that
you see at lunchtime and video the swans on the river. You upload these to your social
networking website where they are automatically tagged with the location and time they
were taken, and with the names of people whose faces the software recognised. Arriving
home, you open the garage doors automatically by keying a number on your phone and



Part I • Essentials of designing interactive systems

in the evening you spend an hour or so on the games machine, watch TV and program the
set top box to record a late-night show.

This is the world we are living in and the world that designers of interactive systems
are designing for. The huge range of interactions that we engage in and the interfaces
that we use offer an exciting if daunting challenge. Moreover, increasingly designers are
having to deal with the issue of people engaged in multiple interactions with different
devices in parallel. One important commentator, Bruce ‘Tog’ Tognazinni, prefers the
term ‘interaction architect’ to describe this profession.

How we got here

Chapter 12 discusses

The revolution that has brought us to where we are today started towards the end of
the Second World War, in 1945, with the development of the first digital computers.
These were huge machines housed in specially built, air-conditioned rooms. They were
operated by scientists and specialist computer programmers and operators, who physi­
cally pressed switches and altered circuits so that the electronics could complete their
During the 1960s computer technology was still dominated by scientific and account­
ing applications. Data was stored on paper tape or cards with holes punched in them, on
magnetic tapes and large magnetic disks, and there was little direct interaction with the
computer. Cards were sent to the computer centre, data was processed and the results
were returned a few days later. Under the guidance of ‘Lick’ Licklider, however, things
were beginning to change. The first screens and cathode ray tubes (CRTs) were being
used as interactive devices and the first vision of a computer network - an internet - was
formulated by Licklider. He worked at the Advanced Research Projects Agency (ARPA)
at the US Department of Defense. His work also led to the establishment of computer
science at four US universities (Licklider, 2003). Licklider was followed by the pioneer­
ing work of Ivan Sutherland at MIT, Doug Englebart who is credited with inventing the
computer mouse, and Ted Nelson who developed the concept of hypertext, the idea of
linking objects and being able to jump directly from one object to the next. In the UK
pioneering work on computers was based at Manchester University and in 1959 Brian
Shackel had published the paper ‘Ergonomics for a computer’.
During the 1970s computing technology spread into businesses and screens
linked to a central computer began to emerge. Computers were becoming networked
together and indeed the first e-mail was sent over the ARPANET in 1972. The method
of interaction for most people in the 1970s was still primarily ‘batch’; transactions
were collected together and submitted as a batch of work and computing power was
shared between different people. Interest in HCI began to grow, with publications
in the International Journal of Man-Machine Studies. As the decade ended so key­
boards and screens became more common, but it was not until 1982 that the first real
graphically based interfaces appeared in the form of the Xerox Star, Apple Lisa and
Apple Macintosh computers. These used a bit-mapped display, allowing a graphical
user interface (GUI) and interaction through pointing at icons and with commands
grouped into menus. This style became ubiquitous when, in 1985, the Windows oper­
ating system appeared on (what were then usually IBM) personal computers (PCs).
The personal computer and Windows-like operating system are attributed to another
important pioneer, Alan Kay. Kay obtained his PhD, studying under Ivan Sutherland,
in 1969, before moving to Xerox Palo Alto Research Center (PARC). It was here that
the object-oriented computer programming language Smalltalk was developed. Many
argue that it was the development of the VisiCalc spreadsheet program on the Apple

Chapter 1 • Designing interactive systems: a fusion of skills

II computer (the ‘killer app’) in 1979 that really fired the personal computer market
(Pew, 2003).
The 1980s was the decade of the microcomputer, with the BBC Micro home computer
selling over 1 million units and a whole plethora of home computers being adopted
worldwide. Games consoles were also gaining in popularity in the home entertainment
market. In business, people were getting networked and the Internet began to grow,
based around e-mail. It was during the 1980s that human-computer interaction (HCI)
came of age as a subject. In both the USA and Europe the first big conferences on HCI
were held: the CHI ’83 conference on Human Factors in Computing Systems in Boston,
MA, and INTERACT ’84 in London. Don Norman published his famous paper ‘The trou­
ble with UNIX: the user interface is horrid’ (Norman, 1981) and Ben Shneiderman pub­
lished Software Psychology (Shneiderman, 1980).
In the 1990s colour and multimedia arrived on the PC, which had begun to domi­
nate the computer market. In 1993 a new interface was produced that took advantage
of a simple mark-up or specification ‘language’ (called hypertext mark-up language,
HTML). Thus the ‘World Wide Web’ came about and revolutionized the whole process
of transmitting and sharing files. Pictures, movies, music, text and even live video links
were suddenly available to everyone at work and at home. The growth of personal, com­
munity and corporate websites was phenomenal and the vision of a wholly connected
‘global village’ community began to become a reality. Of course, this growth was pri­
marily in the West and in the USA in particular, where ‘broadband’ communications
enabled a much more satisfying experience of the Web than the slow connections in
Europe. Many parts of the world were not connected, but in the twenty-first century
connections to the Web are global.
By the turn of the century the convergence of communications and computing
technologies was just about complete. Anything could potentially be connected to
anything, anywhere. Since all the data was digital, it could all be transmitted over the
airwaves or over wired networks, and it could easily be transformed from one form into
another. The proliferation of mobile devices, coupled with the wide availability of the
Internet, brings us to the age of ‘ubiquitous computing’, a term first coined by the late
Mark Weiser in 1993 when he talked of interaction through ‘pads, tabs and boards’.
Computing devices are now pervasive amongst people and across the world, providing
all manner of services and experiences. Computing power continues to double every
18 months or so (according to Moore’s law), producing mobile devices that are more
powerful now than the largest computers were even just a few years ago. In the twentyfirst century computing is truly ubiquitous and interaction is increasingly through touch
and gesture rather than the keyboard that has been the main method of input since the
PC revolution began. We now have Weiser’s pads, tabs and boards in the form of phones
and tablets in various sizes, large public screens and wearable computing (Figure 1.8).
They all have access to the Web and run different apps. A huge amount of data is stored,
and there are billions of videos on YouTube and photos on Flickr. Everything is synchro­
nized and stored in the ‘cloud’ (in reality the cloud is a network of vast data centres full
of computers) and broadband, wireless connectivity is becoming increasingly fast. The
interconnectivity provided by the Web and wireless communications makes this a fasci­
nating time to be an interactive systems designer.

Where are we heading?
It is a brave person who makes any strong prediction about where new technologies
are headed as there are so many confounding factors. It is never just a technology
that wins, but technology linked with a good business model linked with timing. Don



Part I • Essentials of designing interactive systems

Figure 1.8 Tabs, pads and boards
(Source: (tl) Justin Sullivan/Getty images; (bl) Comstock/Alamy Images; (r) Bryan Bedder/Getty Images)

Norman delivers an interesting insight into both the past and future of technologies in
his book The Invisible Computer (1999). Discussing such things as why the VHF video
format succeeded over Betamax and why Edison’s phonograph was not as successful
as Emile Berliner’s, he takes us forward to something he calls ‘information appliances’.
This notion has been taken up by others (Sharpe and Stenton, 2003), providing the fol­
lowing set of characteristics of information appliances:
• Appliances should be everyday things requiring only everyday skills to use.
• Appliances have a clear, focused function that can be used in a variety of
• Peer-to-peer interaction. A key idea of appliances is that they work together without
the need for central control or uploading and downloading.
• Direct user interface. Appliances need to be simple and intuitive to use.
• Successful appliances are those which support the notion of the swift and simple
completion of a task.
• Appliances represent the ability to do something on impulse without having to think
hard about how to do it.
• Appliances are personal and portable.
In 2013 this vision has been achieved to some extent with the range of smartphones
such as the iPhone and Samsung Galaxy. But rather than the appliance concept being
reflected in hardware, it is provided through the thousands of focused applications
Capps’) that are available to download on to the iPhone, the Google Android or one of
the other mobile platforms. Indeed Google along with Amazon are pioneering the idea
of cloud computing where you don’t need to carry any applications or data with you;
just keep them in the cloud and download them when you need them.

Chapter 1 • Designing interactive systems: a fusion of skills

Whom do you trust?
Wireless connectivity between devices is now common both through the 'Wi-fi' stand­
ard called IEEE 802.11 and through Bluetooth. For example, your mobile phone will
connect to your laptop computer via Bluetooth, and the laptop may be connected to
an internal company network via a wireless network and hence to the Internet through
the company's wired connection and hence to any other device in the world. How will
you know where any piece of data that you look at actually is? If you look at the address
book 'in your phone', you might in reality be accessing an address book on your laptop,
or on any computer on the company's network or indeed anywhere on the World Wide
Web. If data is duplicated, how will it be kept consistent? Across which devices will the
consistency be reliable?

What we do know is that new products, business models, services and a range of other
features will rapidly come into the world, and the interactive systems designer has to
be ready to cope. Whether information appliances are just one of many directions that
the future takes, we will have to see. In Microsoft’s vision of HCI in 2020 (Microsoft,
2008) they argue that ‘HCI needs to move forward from concerns about the production
and processing of information toward the design and evaluation of systems that enable
human values to be achieved’ (p. 77) - something also emphasized by Cockton (2009)
and his call for worth-centred design and Bpdker in her consideration of ‘third wave’
HCI (Bodker, 2006)
The design company IDEO undertakes a wide range of projects in interactive systems
design as illustrated through some of their projects illustrated in Figure 1.9 (the pro­
ject shown in Figure 1.9 dates back to 2001). Some projects explore different ideas of
changing concepts such as identity, others aim to produce new products and others look
to see how people use technologies in their daily lives.

Figure 1.9 Concepts for future business card s and id eas of identity
(Source: IDEO, 2003. Courtesy of IDEO)





Part I • Essentials of designing interactive systems

Challenge 1.3

Visit the website of IDEO and look at their projects. Talk about the ideas with a friend.

1.4 The skills of the interactive system s designer
Designers of interactive systems need a variety of skills and need to understand a vari­
ety of disciplines if they are to be able to do their jobs well. They need the mixture of
skills that allows them to be able to:
• Study and understand the activities and aspirations of people and the contexts
within which some technology might prove useful and hence generate requirements
for technologies
• Know the possibilities offered by technologies
• Research and design technological solutions that fit in with people, the activities
they want to undertake and the contexts in which those activities occur
• Evaluate alternative designs and iterate (do more research and more design) until a
solution is arrived at.
The range of skills and academic disciplines that will contribute to such a person is sig­
nificant. Indeed, it is often the case that no single person possesses all the skills needed for
some design activity, which is why the design of interactive systems is often an affair for a
design team. An interactive systems designer may be involved in a community informa­
tion system project on one occasion, a kiosk for processing photographs on another, a data­
base to support a firm of estate agents on another, and a children’s educational game on
another! Designers of interactive systems cannot be expert in all these fields, of course, but
they must be aware enough to be able to take techniques from different areas, or access
research in different disciplines when appropriate. We group the subjects that contribute to
the design of interactive systems under the headings of knowledge of people, technologies,
activities and contexts, and design, and illustrate the relationships in Figure 1.10 (p. 20).


C h ap ter 7 includes a
discussion o f ethnography
C h ap ter 23 discusses
cognitive psychology and
em bodied cognition

People are social beings, so it is important that the approaches and techniques adopted
in the social sciences are used to understand people and technologies. Sociology is
the study of the relationships between people in society, the social, political and other
groups that they participate in, and the settings in which such relationships take place.
Anthropology is similar but focuses also on the study of culture, biology and language
and on how these have evolved and changed over time. Both use techniques such as
interviews and observation to arrive at their conclusions. A key approach, particularly
in anthropology, is ‘ethnography1, which uses qualitative methods such as observations
and unstructured interviews to produce a description of a particular culture or social
group and its setting. Also related is cultural studies, which looks at people and their
relationship with cultural issues such as identity, but also much more prosaic cultural
activities such as shopping, playing computer games or watching TV. Descriptions tend
to be from a more literary criticism background, informed by experience and reflec­
tion. Psychology is the study of how people think, feel and act. In particular, cognitive
psychology seeks to understand and describe how the brain functions, how language
works and how we solve problems. Ergonomics is the study of the fit between people
and machines. In designing interactive systems, the designer will borrow much from
each of these disciplines, including methods to help understand and design for people.

Chapter 1 • Designing interactive systems: a fusion of skills

The technologies that interactive systems designers need to know about include both
software and hardware. Software engineering has developed methods for specify­
ing and implementing computer programs. Programming languages are used to issue
instructions to any programmable device such as a phone, computer, robot dog or ear­
rings, shirts and chairs. Designers need to be aware of hardware for sensing different
types of data (sensors) and for bringing about some change (actuators, or effectors).
There are many different components available that produce many different effects
and here designers will draw upon engineering knowledge, principles and methods.
Communication between devices uses various communication ‘protocols’. Designers
need to know how different devices can communicate.

Activities and contexts
Interaction will usually take place in the context of some ‘community of practice’. This
term is used to denote groups of people who have shared interests and values and
engage in similar activities. In business communities and organizations, information
systems methods have developed over the years to ensure that information systems are
developed that are effective and meet the needs of people who work there. In particular,
soft systems theory (Checkland and Scholes, 1999) provides a very useful framework
for focusing on the design of interactive systems. Social and organizational psychology
are needed to look at the effects of technological change on organizations, and recently
knowledge management and social computing have become important areas. Finally,
new technologies offer new opportunities as business and interactive systems designers
find that they are sometimes creating whole new ways of working with their designs.

Principles and practices of design from all manner of design disciplines are used in
designing interactive systems. Ideas and philosophy from architecture, garden design,
interior design, fashion and jewellery design all crop up in various ways and different
forms. It is not easy to simply pick up ideas from design disciplines, as much design
knowledge is specific to a genre. Designers need to know the materials they work with
and it is likely that more specialist design disciplines will emerge. One such discipline is
product design, which is itself changing as it takes on board the nature of interactivity.
Product design is an important contributing discipline to the skills of the designer of
interactive systems. Graphic design and information design are particularly important
for issues of information layout and the understandability and aesthetic experience of
products. Human-computer interaction has itself evolved many techniques to ensure
that designs are people-focused.

Challenge 1.4
Imagine that you are put in charge of a design team that is to work on a project
investigating the possibility of a new set of Web services for a large supermarket. These
services will allow connection from any fixed or mobile device from any location, allowing
food items to be ordered and delivered. The client even wants to investigate the idea of a
'smart refrigerator' that could automatically order items when it ran out. What range of
skills might you need and which subject areas would you expect to draw upon?
. . . . ............................. —


---------------- ----- ............. ...........................- ....................... - ....................................................................................

Chap ter 12 discusses
inform ation design



Part I • Essentials of designing interactive systems

Figure 1.10 Disciplines contributing to interactive system s design

1.5 Why being human-centred is important
Being human-centred in design is expensive. It involves observing people, talking to
people and trying ideas out with people, and all this takes time. Being human-centred
is an additional cost to any project, so businesses rightly ask whether taking so much
time to talk to people, produce prototype designs and so on is worthwhile. The answer
is a fundamental ‘yes’. Taking a human-centred approach to the design of interactive
systems is advantageous for a number of reasons.

Return on investment
Williams etal. (2007) provide details of a number of case studies looking at the costs of
taking a human-centred approach to interactive systems design and at the benefits that
arise. Paying attention to the needs of people, to the usability of the product, results in

Chapter 1 • Designing interactive systems: a fusion of skills

reduced calls to customer helplines, fewer training materials, increased throughput,
increased sales and so on.
Involving people closely in the design of their systems will help to ensure accept­
ability. Systems will be more effective if they are designed from a human-centred per­
spective and people will be more productive. Nowhere is the economic argument more
pertinent than in Web design and e-commerce sites. Jared Spool and his company User
Interface Engineering have a number of reports demonstrating the importance of good
design to e-commerce and claim that sales can be increased by 225 per cent by turning
‘browsers’ into ‘buyers’.

In the early 1980s there was an accident at a nuclear power plant at Three Mile Island
in the USA that almost resulted in a ‘meltdown’. Reportedly one of the problems was
that the control panel indicated that a valve was closed when it was in fact open, and
another indicator was obscured by a tag attached to another control: two fundamen­
tal design errors - one technical and one organizational - that human-centred design
techniques would help to avoid. Other classic horror tales include a number of plane
and train disasters that have been attributed to faulty displays or to operators not under­
standing or interpreting displays correctly. Systems have to be designed for people and
for contexts. It is no good claiming ‘human error’ if the design was so bad in the first
place that an accident was waiting to happen.

Being human-centred also ensures that designers are truthful and open in their design
practice. Now that it is so easy to collect data surreptitiously and to use that data for
purposes other than what it was intended for, designers need to be ever more vigilant.
As systems are increasingly able to connect autonomously with one another and share
data it is vital that people know where the data that they give is going and how it might
be used. People need to trust systems and be in a position to make choices about privacy
and how they are represented.
The issue of intellectual property is another important aspect of ethical design; it is
very easy to take an image from a website and use it without giving proper acknowl­
edgement for its source. There are many issues associated with plagiarism or other
dishonest uses of written materials. Privacy, security, control and honesty are all signifi­
cant features of the interactive systems designer’s life. Equality and attention to access
are two of the ‘political’ issues that designers must address.
As technology changes so do traditional views and approaches to big moral and
ethical questions. There are standards and legal requirements that need to be met by
designs. Fundamentally, ethical design is needed because the systems that are pro­
duced should be easy and enjoyable to use, as they affect the quality of people’s lives.
Designers have power over other people and must exercise that power in an ethical fash­
ion. The ACM (Association of Computing Machinery) code of ethics gives good advice
on ethical design.

Interactive systems have a big impact on the world, and designers should approach
interaction design from the perspective of what is sustainable. Millions of mobile phones
and other devices are thrown away each year and they contain metals that are poten­
tially dangerous to the environment. Large displays and projectors gobble up power.
Cultures get swamped by the views and values of the dominant suppliers of hardware



Part I • Essentials of designing interactive systems

and software and local languages die out when all information is in English, Chinese
or Hindi. Human-centred design needs to recognize diversity and design to enhance
human values.

Summary and key points
D esigning in teractive system s is a ch alle n g in g and fascinatin g d iscip lin e because it draw s
upon and affects so m a n y features o f people's lives. T h e re is a huge v a rie ty o f in teractive
system s and pro d ucts, fro m business ap p licatio n s o f co m p u te rs to w eb sites to dedicated
in fo rm a tio n a p p lia n ce s to w h o le in fo rm a tio n spaces. D esign in g in te ra ctiv e system s is
co n ce rn ed w ith designing fo r peo ple using techn o lo g ies to u n d ertake activitie s in c o n ­
texts. D esigning in teractive system s needs to be h u m an -ce n tred .

It d raw s u pon m a n y d iffere n t su b ject areas, in clu d in g both en g in ee rin g design and
artistic design.

• It is needed because we live in a digital age when bits are easily transformed and

It is n ecessary if w e are to have safe, effective, eth ical and su stain ab le design.

1 Spend some time browsing the websites of corporations such as IDEO, Sony
and Apple. Do not just look at the design of the site (though that can be useful);
look at the products they are talking about and the philosophy of their design
approach. Collect together your favourites and be prepared to spend time
discussing them with your colleagues. Think of the whole range of issues about
the site: what it looks like, how easy it is to use, how relevant the content of the
site is, how clearly the content is organized, what the overall 'feel' of the site is.

2 Being human-centred is about
• Thinking about what people want to do rather than what the technology
can do
• Designing new ways to connect people with people
• Involving people in the design process
• Designing for diversity.
Writedown how you might approach the design of the supermarket shopping
service discussed in Challenge 1.4. Don't do the design; think about how to
approach the design. Are there any issues of effectiveness, safety, ethics and
sustainability that need to be considered?

Further reading
Laurel, B. (ed.) (1990) The Art of Human-Computer Interface Design. Addison-W esley,
Reading, M A. Although this book is quite old, many of the articles in it are still relevant and
many of the authors of those articles are still at the forefront of interaction design today.

Chapter 1 • Designing interactive systems: a fusion of skills

Norman, D. (1999) The Invisible Computer: Why Good Products Can Fail. M IT Press,
Cambridge, MA. T h is is a n e n jo y a b le b o o k to re a d a b o u t su c c e sse s a n d fa ilu re s, p a sts a n d fu tu re s
f o r te c h n o lo g ie s .

Getting ahead
Friedman, B. and Kahn, P.H. (2007) Human values, ethics and design. In A. Sears and
J. A. Jacko (eds) The Human-Computer Interaction Handbook, 2nd edn. Lawrence Erlbaum
Associates, M ahwah, NJ.

Norman, D. (1993) Things That Make Us Smart. Addison-W esley, Reading, MA.
Norman, D. (1998) The Design of Everyday Things. Addison-W esley, Reading, MA.

T h e se tw o

e a s y - to - r e a d b o o k s p r o v id e a w e a lth o f e x a m p le s o f g o o d a n d b a d d e sig n .

Web links
The Usability Professionals Association is at
The Interaction Design Association is at

The on-line material that goes with this chapter is at

Comments on challenges
Challenge 1.1
Of course, what you say will be dependent on the product or systems chosen. The important thing
is to think in broad terms about the nature of the interaction with the device and at the activities
that the device enables, and how good it is at doing them !
I could talk about the coffee machine at work, which is a simple, functional device. A single but­
ton press produces a reasonable cup of coffee. It is limited, however, in the variety of coffees that
I can get (four types only) so I would ideally prefer a person mixing coffee for me rather than getting
it from a machine. If I stay late at work and have to use the other coffee machine, it is a nightmare.
The money slots don't work properly, the cups are too thin so the drink burns your hands, and the
default is coffee with sugar (which I hate) so I have to remember to press the 'no sugar' button.
Which I frequently forget to do!
This simple device can be contrasted with a website. Choose a website you like to visit. Discuss
the opening page. Is it nice and clean, is there a site map, or other help to get the visitor oriented?
How is the site using images and how does it work with the information? Are things difficult to read
or difficult to control? Look at how users have to navigate from one page to another.

Challenge 1.2
The interface to the microwave consists of the various switches on the front that allow programming
the time and temperature. There is also an audio part - the 'ping' when the timing is finished. The
remote control just uses buttons as the interface and the Xbox controller has various buttons and
a 4-way joystick. The PDA uses a pen (pointer) and a touch-sensitive screen. Icons are used on the
screen and there are a few buttons on the casing. The PDA accepts 'graffiti' handwriting recognition.

Challenge 1.3
The aim of this challenge is to get you to think beyond user interfaces and beyond humancomputer interaction to the changes that new technologies are bringing or could bring. As we
create new information appliances and new products such as business cards, we, you, interactive



Part I • Essentials of designing interactive systems
systems designers, change the world. We change what is possible and change how people interact
with other people. Reflect on (and discuss with someone else, if possible) the political, moral and
ethical issues of these concepts.

Challenge 1.4
This project will demand a wide range of skills. On the technology side there are networking and
software engineering issues concerned with how devices can be programmed to do this and how
the information about products and orders can be stored. There will be issues of authorization and
authentication of payments. Product design may come in if there are to be purpose-built devices
created to access the services (e.g. an in-store smart scanner that could be used to record items
bought). There will be a lot of information design expertise required and some graphic design to
help in the layout of information. On the people side of things, general psychological knowledge
will help to inform the design, and sociology may help to understand the social setting and impact
that such services would have. Business models may need to be developed and certainly the skills
of information systems designers will be needed.










Chapter 2
PACT: a fram ew o rk for
designing interactive system s




An essential part of our approach to designing interactive systems is
that it should put people first: it should be human-centred. We use the
acronym PACT (people, activities, contexts, technologies) as a useful
framework for thinking about a design situation. Designers need to
understand the people who will use their systems and products. They
need to understand the activities that people want to undertake and
the contexts in which those activities take place. Designers also need
to know about the features of interactive technologies and how to
approach designing interactive systems.

Introduction 26

2.2 People 27
2.3 Activities 33
2.4 Contexts 34
2.5 Technologies 36
2.6 Scoping a problem with
Sum m ary and key points 44
Exercises 45
Further reading 45
Web links 45
Com m ents on challenges 46

After studying this chapter you should be able to:
• Understand the relationship between activities and technologies
• Understand the PACT framework
• Understand the main characteristics of people that are relevant to
designing interactive systems
• Understand the main issues of activities and the contexts in which
they occur
• Understand the key features of interactive technologies.


Part I • Essentials of designing interactive systems

2.1 Introduction
People use technologies to undertake activities in contexts. For example, teenagers
use mobile (cell) phones to send text messages to their friends while sitting on a bus.
Secretaries use Microsoft Word to write documents in a firm of solicitors. Air traffic
controllers work together to ensure the smooth operation of an airport. A septuagenar­
ian woman presses various buttons to set the intruder alarms in her house. People use
Facebook to make contact with other people when sitting in an Internet cafe.
In all these settings we see people using technologies to undertake activities in con­
texts and it is the variety of each of these elements that makes designing interactive sys­
tems such a difficult and fascinating challenge. Technologies are there to support a wide
range of people undertaking various activities in different contexts. If the technology is
changed then the nature of the activities will also change. This issue is nicely summed
up in Figure 2.1.

establish requirements for technologies that in turn offer opportunities that change
the nature of activities. And so the cycle continues as the changed activity results in
new requirements for technologies and so on. Designers need to keep this cycle in mind
as they attempt to understand and design for some domain. (The word ‘domain’ here
means an area of study, a ‘sphere of activity’.) For example, as personal computers have
become more common so the domain of e-mail has changed. Originally e-mail was all in
text only, but now it is in full colour with pictures and video embedded. Other items can
be attached to e-mails easily. This has led to a need for better facilities for managing it
for organizing pictures, documents and addresses. Software now keeps track of threads
of e-mails and links between e-mails. Another example is illustrated in Figure 2.2.

Challenge 2.1
T h in k o f th e a c tiv ity o f w a tc h in g a film . List so m e w a y s in w h ic h th is a c tiv ity h a s c h a n g e d
w ith th e in tro d u ctio n o f v id e o c a sse tte reco rd e rs (V C R s ) a n d d ig ita l ve rsa tile d iscs (D V D s) a n d
d o w n lo a d s o n to a la p to p . H o w h a v e th e co n te x ts c h a n g e d sin c e th e e a rly d a y s o f c in e m a ?
........................................................... -

.... ..... .....................................


................................................ - - .......................................................................................................

........................ *

To design interactive technologies we need to understand the variety inherent in the
four elements of PACT.

Chapter 2 • PACT: a framework for designing interactive systems

Figure 2.2 The changing nature of telephoning activity a s technology ad van ces
(Sources: Press Association Images: Susanna Price/DK Images; Mike van der Wolk/Pearson Education Ltd.)

2.2 People
There can be few less controversial observations than that people differ from one
another in a variety of ways. The chapters in Part IV of this book deal with these differ­
ences in detail. Here we summarize some of the most important features.

Physical differences
People differ in physical characteristics such as height and weight. Variability in the five
senses - sight, hearing, touch, smell and taste - has a huge effect on how accessible, how
usable and how enjoyable using a technology will be for people in different contexts.
For example, colour blindness (usually the inability to distinguish correctly between
red and green colours) affects about 8 per cent of Western males, short-sightedness and
long-sightedness affect many, and many people are hearing-impaired. In Europe there
are 2.8 million wheelchair users, so designers must consider where technologies are
placed; and many people have dexterity impairments involving the use of their fingers.
All of us have relatively large fingers compared to the small size we can use for buttons.
Look at the ticket machine in Figure 2.3. What are the physical aspects of people that
need to be taken into account in the design?

The term ‘ergonomics’ was coined in 1948 to describe the study of the relationships
between people and their environment. At that time, technically advanced weapons
systems were being rapidly developed, which required that their design matched
human and environmental factors if they were to be used effectively and, paradoxi­
cally, safely.
The environment includes the ambient environment (temperature, humidity, atmos­
pheric pressure, light levels, noise and so on) and the working environment too (the
design of machines, health and safety issues - e.g. hygiene, toxicology, exposure to ion­
izing radiation, microwaves, etc.).
Ergonomics is multidisciplinary, drawing on anatomy and physiology, various aspects
of psychology (e.g. physiological and experimental), physics, engineering and work
studies among others. In everyday life we come across the application of ergonomic
design principles in every well-designed interactive system. In the advertisement for a
new motor car, we can expect to find reference to its ergonomically designed dashboard



Part I • Essentials of designing interactive systems

Fig u re 2 .3 Metro ticket m achine
(Source: Jules Selmes/Pearson Education)

(a good, desirable feature) or an adjustable, ergonomic driving seat. In the MercedesBenz sales literature for its new coupe we find the following ergonomic description:
O nce inside the C-Class Sports Coupe you'll find a w ealth of ergonom ic detail, designed to
live up to the prom ise of its looks. As if cast from a single mould, the dashboard curves are
smooth to the touch.

The term ‘ergonomic design’ is also extensively used of all manner of office furniture
(chairs, desks, lights, footrests and so forth) and office equipment, for example key­
boards, monitor stands and wrist rests. Many, if not most, of these principles are now
embodied in legally binding design guidelines (see Further reading at the end of this
chapter). Figure 2.4 is an illustration of an ergonomically designed keyboard. It is
described as ergonomically designed as it reflects the fact that we have two hands hence the two separate blocks of keys and an integral wrist support. The keyboard has
been designed to match the hands and fingers of its intended users.

A nthropom etries m eans literally the m easurem ent o f man. A nthropom etries can, for
example, tell us the limits (diam eter and load-bearing characteristics) of the human wrist
for the average man and wom an. Figures have been compiled from thousands o f m eas­
urements o f different races, different ages and different professions (e.g. office workers
vs m anual w orkers) and drawn up as tables. The sam e body o f data w ill also tell the
designer whether the average person can sim ultaneously press button A w hile holding
down buttons B and


and w hether this is true for both right- and left-handed people.

The changing role of the thumb
People w h o have grown up w ith m obile phones (o r G am e Boys) tend to use th eir
thum bs w hen others are m ore likely to use th eir fingers. Sadie Plant from W arw ick

......................... -

........................................ —

.. ....... - . . . . ...........................

Chapter 2 • PACT: a framework for designing interactive systems

Figure 2.4 An ergonomic keyboard
(Source: Microsoft Natural Multimedia Keyboard from www/
Keyboard.jpg © 2004 66Microsoft Corporation. All rights reserved. Printed with permission from Microsoft Corporation)

U niversity ( N e w S c ie n tis t , No. 2 3 1 5 ,3 N ovem ber 2001) collected data on m obile phone
usage in nine cities around the w orld, including Beijing, Chicago, London and Tokyo.
She found that the under-25 age group appear to have experim ented with the best way
to interact with a mobile phone, one result of w hich is that now they use their thum bs
to ring doorbells, push doors and point.


While ergonomics has a longer history than HCI, it would be a mistake to perceive it as
being old and out of touch - quite the reverse. Ergonomics has much to tell us about the
design of interactive devices such as a mobile games console, a tablet PC or smartphone.
Figure 2.5 shows an example of the former.



Part I • Essentials of designing interactive systems

Such devices are faced with ergonomic design challenges. For example, we all have
relatively fat fingers compared with how small buttons can be made. In the world of
mobile computing, small is good but too small is bad (too easily lost, too difficult to use,
too easily eaten by the dog). Ergonomics can put numbers on what constitutes small
and usable and what is too small and unusable. The best-known example of ergonomic
knowledge being applied to HCI issues is Fitts’s law (see Box 2.3).

Fitts’s law
Fitts's law is a mathem atical form ula w hich relates the tim e required to move to a target
as a function of the distance to the target and the size of the target itself, say m oving a
pointer using a mouse to a particular button. It is expressed m athem atically as follows:

T(time to move)

^ lo g 2 ( D / S "f~ 0 *5 )

w h ere k ~ 100 ms, D is the distance between the cu rren t (cursor) position and the
target, and S is the size o f the target.
Thus one can calculate the tim e to m ove a distance o f 15 cm to a button o f size
2 cm as
T = 1 0 0 lo g 2( ^ y + 0 . 5 )
= 0.207 seconds
Fitts’s law describes m otor control. The sm aller the target and the greater the distance,
the longer it w ill take to hit the target. Fitts's law can also be used to calculate how
long it would take to type this sentence or, m ore im portantly, a num ber o f tim e-critical
operations such as hitting the brake pedal o f a m otor car, or the likelihood o f hitting
 rather than  or, m ore worryingly,  or .

Psychological differences
Psychologically, people differ in a variety of ways. For example, people with good spatial
ability will find it much easier to find their way around and remember a website than those
with poor ability. Designers should design for people with poor ability by providing good
signage and clear directions. Language differences are of course crucial to understanding,
and cultural differences affect how people interpret things. For example, in the Microsoft
Excel spreadsheet application there are two buttons, one labelled with a cross and the
other a tick. In the USA a tick is used for acceptance and a cross for rejection, but in Britain
either a tick or a cross can be used to show acceptance (e.g. a cross on a voting paper).

Individual differences
There are often large differences in the psychological abilities o f people. Some people
have a good memory, others less so. Som e people can find their w ay around enviro n­
ments better than others, o r m entally rotate objects m ore quickly and accurately. Some
are good at words, others are good at num bers. There are differences in personality,
em otional make-up and ability to w ork under stress. M any tests have been designed to
measure these differences. For exam ple the M yers-Briggs Type Indicator is a series of

........................................................... -....

.......... .................. - - ... - - ..... .........


Chapter 2 • PACT: a framework for designing interactive systems

tests that results in people being classified as one o f 16 personality types. Others clas­
sify people as one of five personality types known as O CEAN : Openness to Experience,
Conscientiousness, Extraversion, Agreeableness, and N euroticism . Designers need to
consider the range o f differences between people and the dem ands that th eir designs
make on people's psychological abilities.

People also have different needs and abilities when it comes to attention and memory
and these can change depending on factors such as stress and tiredness. Most people
cannot remember long numbers or complicated instructions. All people are better at
recognizing things than they are at remembering things. Some people can quickly grasp
how something works, whereas for others it can take much longer. People have had dif­
ferent experiences and so will have different conceptual ‘models’ of things.

Mental models
The understanding and knowledge that we possess of something is often referred to
as a ‘mental model’ (e.g. Norman, 1998). If people do not have a good mental model
of something they can only perform actions by rote. If something goes wrong they will
not know why and will not be able to recover. This is often the case with people using
software systems, but it is also the case with ‘simpler’ domestic systems such as central
heating systems, thermostats and so on. A key design principle is to design things so
that people will form correct and useful mental models of how they work and what
they do.
People develop mental models through interacting with systems, observing the
relationship between their actions and the behaviours of the system and reading any
manuals or other forms of explanation that come with a system. So, it is important that
designers provide sufficient information in the interface (and any accompanying docu­
mentation) for people to form an accurate mental model.
Figure 2.6 illustrates the problem. As Norman set out in his classic exposition of the
issues (Norman, 1986), designers have some conception of the system they have pro­
duced. This may or may not be the same as what the system actually does. Moreover, in
a system of any large size, no single designer will know everything that the system does.

Figure 2.6 The system image



Part I • Essentials of designing interactive systems

Designers design a system’s image that they hope will reveal the designers’ conception.
The problem is that it is only through the system image - the interface, the behaviours
of the system and any documentation - that the designers’ conception can be revealed.
People interact with the system image and from this have to derive their conception
(their ‘mental model’) of what the system is and what it does. A clear, logical and con­
sistent conceptual design will be easier to communicate to people who use the system
and hence they will develop a clearer conception of the system themselves.
Norman has made the following general observations about the nature of mental
models of interactive systems (Norman, 1983). He concludes that:
• Mental models are incomplete. People will understand some parts of a system better
than others.
• People can ‘run’ (or try out) their models when required, but often with limited
• Mental models are unstable - people forget details.
• Mental models do not have firm boundaries: similar devices and operations get
confused with one another.
• Mental models are unscientific, exhibiting ‘superstitious’ behaviour.
• Mental models are parsimonious. People are willing to undertake additional physical
operations to minimize mental effort, e.g. people will switch off the device and start
again rather than trying to recover from an error.

Chapter 22 discusses the
'mind's eye' in terms of the
visuospatial sketchpad of
working memory

The psychologist Stephen Payne (1991, pp. 4—6) describes how mental models predict
behaviour. The claim is that, in many situations, a great deal of explanatory work
can be done by a description of what people know and believe, and how this affects their
behaviour. Inferences can be made by ‘mental simulation’. Mental models can support
reasonjn„ about devices, or the physical world in general, by running simulations in the
mind’s eye.

Challenge 2.2
W hat is y o u r m e n ta l m o d e l o f e - m a il? H o w d o e s a n e - m a il m e s sa g e g e t fr o m o n e
p la c e to a n o t h e r ? W rite d o w n y o u r u n d e rs ta n d in g a n d d isc u ss it w ith a c o lle a g u e . W h a t
d iffe re n c e s a re th e re a n d w h y ? T h in k a b o u t th e le v e l o f d e ta il (o r le v e l o f a b s tra c tio n ) th a t
is p re s e n t in d iffe r e n t m o d e ls.


..............------ -- ------------------------------------------ -------- J

Device models
Kieras and Bovair (1984) investigated the role o f a device m odel (a person's m en-


tal model o f a device) in learning how to operate a mock-up o f the w eapons control
panel o f the U S S E n te rp ris e from S t a r Trek. In their first experim ent subjects learned how
to operate the 'phasers' either by means o f rote learning (press this button, then turn
that knob to the second position) or by learning the underlying principles (the energy
booster takes pow er from the ship), w hich required the subjects to infer the pro ce­
dures. Kieras and Bovair found that learning, retention and use o f 'shortcuts' w ere all
enhanced fo r the group that learned the principles, dem onstrating that knowledge of
how the system w orked enables people to infer how to operate it. Kieras and Bovair
concluded by making tw o key points: first, fo r a device model to be useful it m ust sup­
port inference about exact and specific control actions, and secondly, the model need
not be very com plete o r thorough.




_____ ___


Chapter 2 • PACT: a framework for designing interactive systems

Social differences
People make use of systems, products and services for very different reasons. They have
different goals in using systems. They have different motivations for using systems.
Some people will be very interested in a particular system, others will just want to get a
simple task completed. These motivations change at different times.
Novice and expert users of a technology will typically have very different levels of
knowledge and hence requirements for design features. Experts use a system regularly
and learn all sorts of details, whereas a beginner will need to be guided through an
interaction. There are also people who do not have to use a system, but who the designer
would like to use the system. These people (sometimes called ‘discretionary users’) are
often quickly put off if things are difficult to do. Designers need to entice these people
to use their systems.
Designing for homogeneous groups of people - groups who are broadly similar and
want to do much the same things - is quite different from designing for heterogeneous
groups. Websites have to cater for heterogeneous groups and have particular design
concerns as a result. A company’s intranet, however, can be designed to meet the partic­
ular needs of particular people. Representatives from a relatively homogeneous group secretaries or managers or laboratory scientists, say - could be made part of the design
team and so provide much more detailed input as to their particular requirements.

Challenge 2.3
Look again at the ticket machine in Figure 2.3 and consider the people who will use it.
Identify the variety of characteristics, physically, psychologically (including different
mental models people might have) and socially, in terms of usage of the system.

..............- -................... ................. — ---- -------- --- ■
---- ------— ----- J

2.3 Activities
There are many characteristics of activities that designers need to consider. The term
is used for very simple tasks as well as highly complex, lengthy activities, so designers
need to be careful when considering the characteristics of activities. Below is our list of
the 10 important characteristics of activities that designers need to consider. First and
foremost, the designer should focus on the overall purpose of the activity. After that the
main features are:

Temporal aspects (items 1-4)
Cooperation (5)
Complexity (6)
Safety-critical (7 and 8)
The nature of the content (9 and 10).
1 Temporal aspects cover how regular or infrequent activities are. Something that is
undertaken every day can have a very different design from something that happens
only once a year. People will soon learn how to make calls using a mobile phone, but
may have great difficulties when it comes to changing the battery. Designers should
ensure that frequent tasks are easy to do, but they also need to ensure that infre­
quent tasks are easy to learn (or remember) how to do.
2 Other important features of activities include time pressures, peaks and troughs of
working. A design that works well when things are quiet can be awful when things
are busy.



Part I • Essentials of designing interactive systems

-> There are many examples
of cooperative activities in
Chapter 18

3 Some activities will take place as a single, continuous set of actions whereas others
are more likely to be interrupted. If people are interrupted when undertaking some
activity, the design needs to ensure that they can ‘find their place’ again and pick up.
It is important then to ensure that people do not make mistakes or leave important
steps out of some activity.
4 The response time needed from the system must be considered. If a website takes
two minutes to deliver a response when the server is busy, that may be frustrating
for a normal query but it could be critical if the information is needed for some
emergency. As a general rule people expect a response time of about 100 millisec­
onds for hand-eye coordination activities and one second for a cause-effect rela­
tionship such as clicking a button and something happening. Anything more than
five seconds and they will feel frustrated and confused (Dix, 2012).
5 Another important feature of activities is whether they can be carried out alone or
whether they are essentially concerned with working with others. Issues of aware­
ness of others and communication and coordination then become important.
6 Well-defined tasks need different designs from more vague tasks. If a task or activ­
ity is well defined it can be accomplished with a simple step-by-step design. A vague
activity means that people have to be able to browse around, see different types of
information, move from one thing to another and so on.
7 Some activities are ‘safety-critical’, in which case any mistake could result in an injury
or a serious accident. Others are less so. Clearly, where safety is involved designers
must pay every attention to ensuring that mistakes do not have a serious effect.
8 In general, it is vital for designers to think about what happens when people make
mistakes and errors and to design for such circumstances.
9 It is also important to consider the data requirements of the activity. If large
amounts of alphabetic data have to be input as part of the activity (recording names
and addresses, perhaps, or word-processing documents) then a keyboard is almost
certainly needed. In other activities there may be a need to display video or highquality colour graphic displays. Some activities, however, require very modest
amounts of data, or data that does not change frequently, and can make use of other
technologies. A library, for example, just needs to scan in a barcode or two, so the
technology can be designed to exploit this feature of the activity.
10 Just as important as data is the media that an activity requires. A simple two-tone
display of numeric data demands a very different design from a full-motion multi­
media display.


Activities always happen in a context, so there is a need to analyse the two together. Three
useful types of context are distinguishable: the organizational context, the social context
and the physical circumstances under which the activity takes place. Context can be a

Chapter 2 • PACT: a framework for designing interactive systems

difficult term. Sometimes it is useful to see context as surrounding an activity. At other
times it can be seen as the features that glue some activities together into a coherent
For an activity such as ‘withdraw cash from an ATM’, for example, an analysis of
context would include things such as the location of the device (often as a ‘hole-inthe-wall’), the effect of sunshine on the readability of the display, and security consid­
erations. Social considerations would include the time spent on a transaction or the
need to queue. The organizational context for this activity would take into considera­
tion the impact on the bank’s ways of working and its relationships with its customers. It
is important to consider the range of contexts and environments in which activities can
take place.

Physical environment
The physical environment in which an activity happens is important. For example, the
sun shining on an ATM display may make it unreadable. The environment may be very
noisy, cold, wet or dirty. The same activity - for example, logging on to a website - may
be carried out in geographically remote environments where Internet access is slow, or
with all the facilities of a large city and fast networks.

Social context
The social context within which the activity takes place is also important. A supportive
environment will offer plenty of help for the activity. There may be training manuals
available, tuition or experts to hand if people get into trouble. There may be privacy
issues to consider, and an interaction can be very different if the person is alone com­
pared to being with others. Social norms may dictate the acceptability of certain designs.
For example, the use of sound output is often unacceptable in an open-plan office envi­
ronment, but might be quite effective where a person is working alone.

Organizational context
Finally the organizational context (Figure 2.7) is important as changes in technology
often alter communication and power structures and may have effects on jobs such as
deskilling. There are many books devoted to the study of organizations and the impact
of new technologies on organizations. We cannot do justice to this subject here. The cir­
cumstances under which activities happen (time, place and so on) also vary widely and
need to be taken into consideration.

Figure 2.7 Different working contexts
(Source: Peter Wilson/DK Images; Rob Reichenfield/DK Images: Eddie Lawrence/DK Images)



Pari I • Essentials of designing interactive systems

Interface plasticity
Joelle Coutaz and her colleagues (Coutaz and Calvary, 2012) present the idea of design­
ing for interface plasticity. These are interfaces that adapt to different contexts, for
example adapting a display of a heating controller from a display on the TV to a display
on a small mobile device. Importantly they tie this in with the idea of designing for
specific values. Designers should explicitly address the values that are being sought for
people in a specific context. The interface should be designed to achieve the required
values in the required contexts of use.




_ ___




_ ___


2.5 Technologies
The final part of the PACT framework is the technologies: the medium that interactive
system designers work with. Interactive systems typically consist of hardware and soft­
ware components that communicate with one another and transform some input data
into some output data. Interactive systems can perform various functions and typically
contain a good deal of data, or information content. People using such systems engage in
interactions and physically devices have various degrees of style and aesthetics. Designers
of interactive systems need to understand the materials they work with, just as designers
in other areas of design such as interior design, jewellery design, etc. have to do.
Of course, interactive technologies change at a fantastic rate and by far the best
way for designers to keep abreast of the options available is to subscribe to websites, a
number of which are listed on the website that accompanies this chapter. It is also very
difficult to classify technologies, as they are continually being packaged in new ways
and different combinations facilitate quite different types of interactions. For example,
the multi-touch screen on an iPod Touch allows for quite different ways of navigating
through your music collection and selecting particular tracks from the trackwheel on an
iPod Nano. Designers need to be aware of various possibilities for input, output, com­
munication and content.

Input devices are concerned with how people enter data and instructions into a system
securely and safely. Switches and buttons facilitate a simple and direct method of issu­
ing instructions (such as ‘turn on’ or ‘turn off’) but they take up space. On small mobile
devices there is not enough room to have many buttons, so designers have to be careful
which functions have their own button. On the iPhone, for example, a button on the side
of the device is allocated to turning the sound off and on. The designers decided that
this was such an important and often-used function that it should have its own button.
Alphanumeric data is usually input to an interactive device through a ‘QWERTY’ key­
board, invented by C.L. Sholes in 1868! At that time, typewriters were relatively crudely
manufactured and an alphabetic arrangement of keys tended to result in jams when the
keys were struck. By rearranging the keys Sholes solved this problem. The design is still
with us today, despite some devices using an alphabetic keyboard where the letters are
arranged in alphabetical order.
Touchscreens are sensitive to the touch of a finger. They function through either infra­
red sensitivity or electrical capacitance. Because of their lack of moving or detachable
parts, they are suitable for applications intended for public places, and provided the

Chapter 2 • PACT: a framework for designing interactive systems

interface is well designed they present an appearance of simplicity and ease of use. Many
touchscreens only recognize a single touch, but multi-touch screens enable zooming and
rotating of images and text. Figure 2.8 shows Microsoft’s surface, a multi-touch table.
Touchscreens make use of the person’s finger as the input device, which has the obvious
benefit that people always have their fingers with them. The light pen (Figure 2.9) was,
arguably, the original pointing device. When it is pointed at the screen it returns infor­
mation about the screen location to a computer which allows the item pointed at to be
identified. Light pens are less expensive than touchscreens, can be armoured (made very
robust) and can be sterilized. They have a number of industrial and medical applications.
Other forms of pointing device include the stylus which is used on very small displays
where a finger is too big to be used as the input device, and on many handheld devices.
Being more precise than a finger, a stylus can be used for handwriting recognition. In
theory, this is an attractive way of inputting data into an interactive device. Writing with
a stylus directly onto a computer’s screen or tablet is a natural way of working. However,
it is quite slow and can be inaccurate. It requires people to ‘train’ the device to recognize
their handwriting, which improves the recognition accuracy of the software. Many peo­
ple can type faster than they can write by hand.
One of the most ubiquitous of input devices is the mouse (Figure 2.10), developed
at Stanford University Research Laboratory in the mid-1960s. The mouse consists of a
palm-sized device that is moved over a flat surface such as the top of a desk. At its sim­
plest (and cheapest) it rests on a rubber-coated ball that turns two wheels set at right
angles. These two wheels translate the movement of the mouse into signals that the com­
puter to which it is connected can interpret. One or two buttons sit on top of the mouse
and are operated with the person’s fingers. The mouse has become the default pointing
device. More contemporary mouse design includes a thumbwheel (see Figure 2.11) for
scrolling through documents or Web pages. A mouse may be cordless, using infra-red to
communicate with the host computer. In 2009 Apple introduced the ‘magic mouse’ that
combined traditional mouse functions with multi-touch capability allowing a range of
new touch gestures for interaction.
A trackball is another pointing device, which is best described as a mouse lying on its
back. To move the pointer the user moves the ball. Again, like all other pointing devices,
there are one or more buttons which can be used to select on-screen items. Trackballs
are often found in public-access kiosks because they are difficult to steal and do not
require a flat surface to rest upon.

Figure 2.8 Microsoft Surface

Figure 2.9 A light pen

(Source: Reuters/Robert Sorbo)

(Source: Volker Steger/Science Photo Library)



Part I • Essentials of designing interactive systems

Figure 2.10 A Mac one-button mouse. The
single button of the traditional Mac is said
to have the advantage of 'you always know
which button to press'
(Source: Alan Mather/Alamy Images)

Figure 2.11 A Microsoft two-button mouse
with thumbwheel (which is used for
hardware/BNMS_mouse_web.jpg. Printed with permission
from Microsoft Corporation)

A joystick (Figure 2.12) is a handle which pivots from a central point. Viewing
the joystick from above, it may be moved north, south, east and west (and all points
between) to control an on-screen pointer, spaceship or any other on-screen object.
Joysticks are used mostly for computer games, but they are also found in conjunction
with CAD/CAM (computer-aided design/manufacture) systems and VR (virtual real­
ity) applications.
With the introduction of the Nintendo Wii in 2007 a whole new generation of input
became possible. The Wii uses infra-red to register the movement of a wand. This allows
gestures to be recognized. Other systems, notably the Microsoft Kinnect, recognize ges­
tures through tracking limb and body movements by attaching sensors to the limb or by
tracking using cameras (Figure 2.13).
There are many different types of sensor that are now available as input mechanisms.
Air pressure sensors, acoustic sensors, vibration detectors, infra-red motion detectors
and accelerometers are all readily available for designers to detect specific aspects of an

Figure 2.12 An ergonomically designed
games joystick
(Source: Microsoft Sidewinder® Precision 2 joystick.
Photo by Phil Turner. Printed with permission from
Microsoft Corporation)

Chapter 2

PACT: a framework for designing interactive systems

Figure 2.13 Microsoft Kinnect
(Source: David Becker/Getty Images)

interaction. Wilson (2012) lists sensors for detecting occupancy, movement and orien­
tation, object distance and position, touch, gaze and gesture, human identity (biomet­
rics), context and affect. There are many proprietary devices used to input specifically
to mobile devices, such as jog wheels used for navigation of mobile phone interfaces.
Brain activity can also be sensed, allowing for brain-computer interfaces (BCI) - an
exciting development for the future.
Speech input is becoming increasingly accurate, particularly if people are willing
to spend a few minutes (7-10, say) training a system to recognize their voice. Even
without training, the Siri system on the iPhone can be quite impressive. The other day
I said to Siri ‘Send a text to Linda’. Siri replied There are two people called Linda in
your address book, Linda and Linda Jane’. I replied ‘Send a text to Linda Jane, say Hi’.
Siri sent the text and responded, ‘A text saying Hi has been sent to Linda Jane’. Speech
input for these simple, focused tasks will become an increasingly common option for the
interaction designer.
Other forms of input include quick response (QR) codes and augmented-reality (AR)
fiducial markers (Figure 2.14). QR codes are used by a general-purpose scanning app on
a phone to connect the phone to a website, or to execute a short sequence of operations.

Figure 2.14 QR codes
(Source: Red Huber/Orlando Sentinel/
MCT/Getty Images)



Part I • Essentials of designing interactive systems

Fiducial markers are used to recognize an object and hence to tailor some interactivity
towards it. Markerless AR uses a photo of an object to register a connection allowing
graphics, video and other content to be overlaid onto the scene. The Global Positioning
System (GPS) can also be used to align views of the real world with digital content to
provide an augmented reality.

Challenge 2.5
Which input devices would you use for a tourist information 'kiosk' application to be sited
in the arrivals area of an airport? The system allows people to book hotel rooms, etc., as
well as to find information about the area. Explain your choices.


■-............. ........-....

..........................................- ...... -............ J


Wearable computing

is discussed at length
in Chapter 20

Technologies for displaying content to people rely primarily on the three perceptual
abilities of vision, hearing and touch. The most fundamental output device is the screen
or monitor. Even a few years ago the default monitor used cathode ray tube (CRT)
technology that required a large heavy box positioned on a desk or table. Nowadays
flat-screen monitors using plasma or TFT (thin-film transistor) or LCD (liquid crystal
display) technologies can be mounted on walls. Some of these can deliver very large
displays that result in a significantly different interactive experience. Flexible organic
light-emitting diode (OLED) displays for screens are just coming onto the market that
wiU enable displays of any shape and size that can bend and hence can be used in clothing (Figure 2.15)
The physical dimensions of display devices are, however, only one of the factors
involved in the resulting output. The output device is driven by hardware - a graphics
card - that will vary with respect to the screen resolutions and palette of colours it can
support. More generally, designing interactive systems to work with any and all combi­
nations of hardware is very difficult. Typically, applications and games specify minimum

Figure 2.15 Flexible organic light-emitting
diode (OLED) display
(Source: Volker Steger/Science Photo Library Ltd)

Chapter 2 • PACT: a framework for designing interactive systems

One way past the problems with restrictive display ‘real estate’ is to use a data projec­
tor (Figure 2.16). While the resolution is usually less than that of a monitor, the result­
ing projected image can be huge. Data projectors are shrinking in size at a remarkable
rate and there are now mobile data projectors. These promise to have a big impact on
interaction design as they get small enough to be built into phones and other mobile
devices. Images can be projected onto any surface and pointing and other gestures can
be recognized by a camera. In this way any surface has the potential to become a multi­
touch display.
Besides the visual display of content, sound is an important method of output. Sound is
an output medium that is significantly under-used. Speech output is also an increasingly
popular option (e.g. in satellite navigation systems). With effective text-to-speech (TTS)
systems, simply sending a text message to the system results in clear spoken output.
A printer is a device that prints text or illustrations on paper, while a plotter draws
pictures or shapes. Plotters differ from printers in that they draw lines using a pen. As a
result, they can produce continuous lines, whereas printers can only simulate lines by
printing a closely spaced series of dots. Multi-colour plotters use different-coloured
pens. In general, plotters are considerably more expensive than printers.
Several companies have developed three-dimensional printers. These machines work
by placing layers of a powdery material on top of each other to create a real-life model
of a digital image. It is thought that with the use of hundreds and perhaps thousands of
layers, everything from ‘coffee cups to car parts’ could be created. Like putting ink on
paper, 3D printers print using powder and binder (glue). These printers allow for the
rapid prototyping of physical designs for new products.
‘Haptics’ refers to the sense of touch. However, haptics allows us to be in touch
with interactive devices and media in a way that is direct and immediate. Perhaps
the most widespread haptic devices are those games controllers that incorporate
so-called force-feedback. Force-feedback is typically intended to convey feedback from
games environments back to the person engaged. So what are the perceived benefits of
force-feedback devices?
• Sensations can be associated with interactions, such as feeling driving surfaces or
feeling footsteps.
• Sensations can also be used to provide feedback as to the location of other players,
objects and so forth.
• Force-feedback can allow the player to feel what it would be like to wield a sword,
drive a high-speed car, fly a ‘speeder’ or engage the Empire with a light-sabre.

Figure 2.16 The Samsung
i7410 Sirius Projector Phone
(Source: Gaustau Nacarino/Reuters)

Sound is discussed at
length in Chapter 13

Haptic interfaces are
considered further in
Chapter 13



Part I • Essentials of designing interactive systems

A significantly more serious application of force-feedback is NASA’s ‘Softwalls’ initiative
in response to the 9/11 terrorist attacks on New York in 2001. Softwalls would be
used to restrict airspaces by way of the aircraft’s on-board systems. The basic idea,
attributed to Edward Lee, would prevent aircraft from flying into restricted airspace
(such as city centres) and this would be communicated to the pilot by way of the air­
craft’s joystick. Other examples include the ‘silent alert’vibration of a mobile phone and
even the feel of a key when pressed.

Challenge 2.6
Which output devices would you use for a tourist information application as described in
Challenge 2.5? Explain your choices.



------------------------------------------------------------------------------------------------------------------------------ - - - i

Communications between people and between devices is an im portant part of
designing interactive systems. Here, issues such as bandwidth and speed are critical.
So too is feedback to people so that they know what is going on and indeed that some­
thing is going on! In some domains the transmission and storage of large amounts of
data becomes a key feature.
Communication can take place through wired connections such as a telephone line,
or an Ethernet network which is often found in offices. Ethernet is the fastest form
of communication, but the device has to be plugged into a network to make use of it.
Ethernet allows connection to be made to the nearest node on the Internet. Extremely
fast communications over fibre-optic cables connect these nodes to each other and
hence connect devices to other devices all over the world. Each device on this network
has a unique address, its IP (Internet Protocol) address, that enables data to be routed to
the correct device. The number of IP addresses available will soon be used up and a new
form of address, IPv6, will be needed.
Wireless communication is becoming much more common and often a wireless ‘hub’
is attached to an Ethernet network. Wireless communications can take place over the
wireless telephone network used for mobile phones or over a Wi-Fi connection. Wi-Fi
is quite limited in range and you need to be within a few metres of a Wi-Fi hub to get
a connection, whereas over the telephone network, coverage is much wider. The new
4G technologies promise to deliver much faster connectivity over mobile devices and
superfast broadband will soon be covering cities across the globe. Other forms of wire­
less communication continue to be developed and WiMax promises to deliver much
wider coverage using Wi-Fi. Short-range communications directly between one device
and another (i.e. not using the Internet) can be achieved using a technology called
Bluetooth. Near-field communication (NFC) is used to connect devices simply by bring­
ing them close to each other. All new mobile phones will soon have NFC capability,
a feature which again will change the types of interaction that are possible.

Content concerns the data in the system and the form it takes. Considerations of con­
tent are a key part of understanding the characteristics of the activities as described
above. The content that a technology can support is also critical. Good content is
accurate, up to date, relevant and well presented. There is little point in having a

Chapter 2 • PACT: a framework for designing interactive systems

sophisticated information retrieval system if the information, once retrieved, is out of
date or irrelevant. In some technologies content is just about everything (e.g. websites
are usually all about content). Other technologies are more concerned with function
(e.g. a remote control for a TV). Most technologies have a mixture of function and
Content can be retrieved when required (known as ‘pull technology’) or it can be
pushed from a server to a device. Push e-mail, for example, is used on the BlackBerry
system so that e-mail is constantly updated. RSS feeds on websites provide automatic
updates when a website’s content is changed.
The characteristics of the data are important for choosing input methods. Barcodes,
for example, are only sensible if the data does not change often. Touchscreens are use­
ful if there are only a few options to choose from. Speech input is possible if there is no
noise or background interference, if there are only a few commands that need to be
entered or if the domain is quite constrained.
‘Streamy’ outputs such as video, music and speech have different characteristics
from ‘chunky’ media such as icons, text or still photographs. Most important, per­
haps, is that streamy media do not stay around for long. Instructions given as speech
output, for example, have to be remembered, whereas if displayed as a piece of text,
they can be read over again. Animations are also popular ways of presenting con­
tent; 2D animation is generally produced using Adobe’s Flash program and 3D-style
animation can be produced with Papervision or games ‘engines’ such as 3D Studio
Max and Maya.

2.6 Scoping a problem with PACT
The aim of human-centred interactive systems design is to arrive at the best combina­
tion of the PACT elements with respect to a particular domain. Designers want to get
the right mix of technologies to support the activities being undertaken by people
in different contexts. A PACT analysis is useful for both analysis and design activi­
ties: understanding the current situation, seeing where possible improvements can
be made or envisioning future situations. To do a PACT analysis the designer simply
scopes out the variety of Ps, As, Cs and Ts that are possible, or likely, in a domain.
This can be done using brainstorming and other envisionment techniques and by
working with people through observations, interviews and workshops. There are
many techniques for this (these are described in Part II of this book). A PACT analysis
is also useful for developing personas and scenarios (see Chapter 3). The designer
should look for trade-offs between combinations of PACT and think about how these
might affect design.
For people, designers need to think about the physical, psychological and social dif­
ferences and how those differences change in different circumstances and over time.
It is most important that designers consider all the various stakeholders in a project.
For activities they need to think about the complexity of the activity (focused or vague,
simple or difficult, few steps or many), the temporal features (frequency, peaks and
troughs, continuous or interruptible), cooperative features and the nature of the data.
For contexts they think about the physical, social and organizational setting, and for
technologies they concentrate on input, output, communication and content.
As an example, let us assume that we have been asked by a university department to
consider developing a system controlling access to their laboratories. A PACT analysis
might include the following.



Part I • Essentials of designing interactive systems

Students, lecturers and technicians are the main groups. These are all well educated
and understand things such as swipe cards, passwords and so on. People in wheelchairs
need to be considered, as do other design issues such as colour blindness. There may
be language differences. Both occasional and frequent visitors need to be considered.
However, there are other stakeholders who need access to rooms, such as cleaning staff
and security personnel. What are the motivations for management wanting to control
access in the first place?

The overall purpose of the activity is to enter some form of security clearance and to
open the door. This is a very well-defined activity that takes place in one step. It hap­
pens very frequently, with peaks at the start of each laboratory session. The data to be
entered is a simple numeric or alphanumeric code. It is an activity that does not require
cooperation with others (though it may be done with others, of course). It is not safetycritical, though security is an important aspect.

Physically the activity takes place indoors, but people might be carrying books and other
things that makes doing anything complicated quite difficult. Socially it may happen in a
crowd, but also it may happen late at night when no one else is about. Organizationally,
the context is primarily about security and who has access to which rooms and when
they can gain access. This is likely to be quite a politically charged setting.

A small amount of data has to be entered quickly. It must be obvious how to do this in
order to accommodate visitors and people unfamiliar with the system. It needs to be
accessible by people in wheelchairs. The output from the technology needs to be clear:
that the security data has been accepted or not and the door has to be opened if the
process was successful. Communication with a central database may be necessary to
validate any data input, but there is little other content in the application.

Challenge 2.7
Write down a quick PACT analysis for the introduction of a 'point of sale' system
(i.e. where goods are priced and paid for) for a cafe at a motorway service station.
Discuss your ideas with a colleague.

The design of interactive systems is concerned with people, the activities they are under­
taking, the contexts of those activities and the technologies that are used: the PACT ele­
ments. There is considerable variety in each of these and it is this variety - and all the
different combinations that can occur - that makes the design of interactive systems so
• The design of interactive systems requires the analyst/designer to consider the range
of PACT elements and how they fit together in a domain.

Chapter 2 • PACT: a framework for designing interactive systems

• People vary in terms of physical characteristics and psychological differences and in
their usage of systems.
• Activities vary in terms of temporal aspects, whether they involve cooperation, com­
plexity, whether they are safety-critical and the nature of the content they require.
• Contexts vary in terms of physical, social, organizational aspects.
• Technologies vary in terms of the input, output, communication and content that
they support.
• Undertaking a PACT analysis of a situation is a useful way of scoping a design

1 You have been asked to design the information system for a new cycle path
network that is to run through part of your town. The aim of the system is to
provide information on directions and distances for leisure cyclists to the main
points of interest in the town. It also needs to provide information on other
things, such as bus and train times for those cyclists who are commuting to
and from work. Undertake a PACT analysis for this application.

2 For the same application produce a project development plan. You should
detail what sort of requirements work will be needed to understand the
domain, the people or skills that will be needed in the project team, and the
approach that will be taken. Identify any milestones that you would have in
the project.

Further reading
Norman, D. (1998) The Design of Everyday Things. Doubleday, New York. Donald Norman
discusses the ideas of mental models in several of his publications. This is probably the best.

Getting ahead
Murrell, K.F.H. (1965) Ergonomics - Man in his Working Environment. Chapman & Hall,
Payne, S. (2012) Mental models. In J.A. Jacko (ed) The Human-Computer Interaction
Handbook: Fundamentals, Evolving Technologies and Emerging Applications, 3rd edn. CRC
Press, Taylor and Francis, Boca Ratun, FL.
Wilson, A. (2012) Sensor and recognition-based input for interaction. In J.A. Jacko (ed)
The Human-Computer Interaction Handbook: Fundamentals, Evolving Technologies and
Emerging Applications, 3rd edn. CRC Press, Taylor and Francis, Boca Ratun, FL.

Web links
The accompanying website has links to relevant websites. Go to



Part I • Essentials of designing interactive systems

Comments on challenges
Challenge 2.1
With VCRs came the video hire shop and so the activity of watching a film moved from the
cinema into the home. VCRs also allowed films to be recorded from the television so people
could watch them whenever they wanted. With DVDs people are given more options than just
watching the film, so now the activity includes watching pieces that were cut out of the original
film, slightly different versions, interviews with the actors and director and so on. The activity
of watching a film is now more interactive: the people watching have more control over what
they see.

Challenge 2.2
How an e-mail actually gets from one place to another is surprisingly complicated! It is much more
like sending a letter by post than like making a telephone call. The e-mail is sent as one or more
'packets' of data which may be routed across the world by any of a host of different routes. The
e-mail travels from your computer through the computer providing the Internet connection, then
to a major 'hub' where it joins a high-capacity 'backbone' cable. As it comes closer to its destination
this process is reversed as it moves off the main cables into more remote areas. A sophisticated
database of addresses and routeing information is used to find the best way.

Challenge 2.3
Physically the siting is important so that people in wheelchairs, children, etc. can reach the buttons.
Buttons must be easy to press so that the elderly are not excluded from their use. Psychologically
the machine should not make undue demands on people. It is difficult to say anything certain
since we do not know the complexity of the machine. Some ticket machines are very simple designed just to select the destination and deliver the ticket. Others try to offer the whole range
of functions, different ticket types, groups, period return tickets and so on. These machines tend
to become very complicated and hard to use. From the usage perspective the design needs to
support both those people who are in a hurry and perhaps use the machine every day and those
people who have never encountered such a machine before, perhaps speak a different language
and are trying to do something quite complex. It is difficult to design optimally for both of these
types of use.

Challenge 2.4
Sending e-mails is a fairly frequent activity that is often interrupted. It is a straightforward activity
in itself but it can become very complex when it is interleaved with other things such as finding old
e-mails, finding addresses, attaching documents and so on. It is not necessary to coordinate the
activity with others. The tasks of finding and entering addresses are made much easier if the e-mail
program has an embedded address book, as the person only has to remember and type small
amounts of data. Otherwise long e-mail addresses have to be typed in.

Challenge 2.5
For reasons of durability, we would suggest a touchscreen or ordinary monitor with tracker ball and
a robust keyboard (for entering data such as name of hotel guest) or an on-screen version (rather
tiresome to use). Other options are possible.

Challenge 2.6
The touchscreen used as an output device, plus a small printer embedded in the casing for con­
firmation of bookings, etc. would probably be more reassuring than just a confirmation number.
Sound output (and indeed input) would be possible but is likely to be impractical in the noisy
environment of the airport.

Chapter 2 • PACT: a framework for designing interactive systems

Challenge 2.7
There are many complex issues involved, of course. Here are just a few to start with. People - the
whole range! From a coachload of football supporters or elderly people on an outing to individu­
als wandering around late at night. The key thing to consider is how to deal with crowds at one
time and just a few people at another. The activities are simple and well defined. The items have to
be identified, priced and totalled. The money has to be taken and a receipt printed. Occasionally
there will be a question to be answered that goes outside this simple task structure, such as 'how
much would this cost if I . . . ?', or disputes over prices need to be settled. There are also other

stakeholders involved: the serving staff, the managers and so on. They also need information from
the system. As for technologies, items could have a barcode on them, but for meals this is difficult,
so usually individual items need to have the price typed in. This takes time. The interface design
will be quite critical - e.g. there could be specific keys for things like tea and coffee, but whether it
is a good idea to have a specific key for everything is another matter. Now you have had a chance
to think about this, spend some time looking at all the different solutions that different cafes and
restaurants use.



Chapter 3




The p ro cess of hum an-centred
interactive system s design




Design is a creative process concerned with bringing about something
new. It is a social activity with social consequences. It is about
conscious change and communication between designers and the
people who will use the system. Different design disciplines have

Introduction 49

3.2 Developing personas and
scenarios 55

3.3 Using scenarios throughout
design 62
3.4 A scenario-based design
method 66

different methods and techniques for helping with this process.

Further reading 73

Approaches to and philosophies of design change over time. In mature
disciplines, examples of good design are built up and people can study
and reflect upon what makes a certain design great, good or awful.
Different design disciplines have different constraints, such as whether
the designed object is 'stand-alone' or whether it has to fit in and live

Web links 74

with legacy systems or conform to standards.

Comments on challenges 74

In this chapter we look at what is involved in interactive systems design
and how to go about designing interactive systems. After studying this
chapter you should be able to:

Sum m ary and key points 73

Exercises 73

• Understand the nature of interactive systems design
• Understand the four processes involved in design: understanding,
design, envisionment, evaluation
• Understand the centrality of evaluation in human-centred design
• Understand the scenario-based design approach
• Develop scenarios and personas
• Understand the scenario-based design method.

Chapter 3 • The process of human-centred interactive systems design

3.1 Introduction
There are many different ways of characterizing the activities involved in the design
process. For David Kelley, founder of the product design company IDEO, ‘Design has
three activities: understand, observe and visualize’. He says:
Remember, design is messy: designers try to understand this mess. They observe how their
products will be used; design is about users and use. They visualize which is the act of
deciding what it is.
Kelley and Hartfield (1996), p. 156

In this chapter we provide methods and processes to help designers deal with the ‘messy1
problems of designing interactive systems. We characterize the overall design process in
terms of the four activities illustrated in Figure 3.1. The key features of this representa­
tion are as follows:
• Evaluation is central to designing interactive systems. Everything gets evaluated at
every step of the process.
• The process can start at any point - sometimes there is a conceptual design in place,
sometimes we start with a prototype, sometimes we start with understanding.
• The activities can happen in any order, for example understanding might be evalu­
ated and a prototype built and evaluated and some aspect of a physical design might
then be identified.

Figure 3.1 Understanding, design, evaluation, envisionment



Part I • Essentials of designing interactive systems


-» Chapter 7 gives a
detailed treatment of
m ethods for understanding

Understanding is concerned with what the system has to do, what it has to be like and
how it has to fit in with other things: with the requirements of the product, system or
service. Designers need to research the range of people, activities and contexts relevant
to the domain they are investigating so that they can understand the requirements of
the system they are developing. They need to understand the opportunities and con­
straints provided by technologies.
There are both functional and non-functional requirements to consider. Functional
requirements are concerned with what the system should be able to do and with the
functional constraints of a system. It is important for the designer to think about the
whole interaction experience in an abstract way. Deciding who does what, when some­
thing should be displayed or the sequence in which actions are undertaken should come
later in the design process. A good analysis of an activity will strive to be as independent
of current practice as possible. Of course, there are always functional constraints - the
realities of what is technically possible - which render certain ordering, sequencing and
allocation of functions inevitable. There are also logical and organizational constraints
that may make particular designs infeasible.
Requirements are generated through discussions and interactions with people
who will use or be affected by the proposed system - the stakeholders (see Box 3.1).
Requirements are also generated through observations of existing systems, research
into similar systems, what people do now and what they would like to do. Requirements
can be generated through working with people in focus groups, design workshops and
so on, where different scenarios can be considered (see Section 3.4). The aim is to
collect and analyse the stories people have to tell. Requirements are essentially about

'Stakeholders' is a term that refers to all the people who will be affected by any system
that results from the process of interactive systems design. This includes the people who
will finish up using the new system (sometimes called the 'users'), but it also includes
many other people. For example, the organization that the system is being designed
for will probably have many people in it that will not be using the system, but will be
affected by it as it might change their job. For example, introducing a new website into
an organization often changes working practices as well as simply providing informa­
tion. There may be stakeholders outside the organization, such as government authori­
ties, that need to verify some procedures. The number and type of people affected
by a new interactive system will vary greatly according to what sort of system it is. An
important part of the understanding process is to consider all the different stakeholders
and how they might be affected, to decide who should be involved in discussions about
the design.

Design activities concern both conceptual design and physical design. Conceptual
design is about designing a system in the abstract, physical design is concerned with
making things concrete.

Chapter 3 • The process of human-centred interactive systems design

Conceptual design
Conceptual design is about considering what information and functions are needed for
the system to achieve its purpose. It is about deciding what someone will have to know
to use the system. It is about finding a clear conceptualization of a design solution and
how that conceptualization will be communicated to people (so that people will quickly
develop a clear mental model).
There are a number of techniques to help with conceptual design. Software engi­
neers prefer modelling possible solutions with objects, relationships and ‘use cases’ (a
semi-formal scenario representation). Entity-relationship models are another popular
conceptual modelling tool. Flow can be represented using dataflow diagrams and struc­
ture can be shown with structure charts. The conceptual design of a website, for exam­
ple, will include a site map and a navigation structure.
One way to conceptualize the main features of a system is to use a ‘rich picture’. Two
examples are shown in Figure 3.2. A rich picture captures the main conceptual relation­
ships between the main conceptual entities in a system - a model of the structure of a situ­
ation. Peter Checkland (Checkland, 1981; Checkland and Scholes, 1999), who originated
the soft systems approach, also emphasizes focusing on the key transformation of a sys­
tem. This is the conceptual model of processing. The principal stakeholders - customers,
actors, system owners - should be identified. The designer should also consider the per­
spective from which an activity is being viewed as a system (the Weltanschauung) and
the environment in which the activities take place. (Checkland proposes the acronym
CATWOE - customers, actors, transformation, Weltanschauung, owners, environment for these elements of a rich picture.) Most importantly, the rich picture identifies the
issues or concerns of the stakeholders, thus helping to focus attention on problems or
potential design solutions.
The key feature of conceptual design is to keep things abstract - focus on the ‘what’
rather than the ‘how’- and to avoid making assumptions about how functions and infor­
mation will be distributed. There is no clear-cut distinction between conceptual and
physical design, but rather there are degrees of conceptuality.

Physical design
Physical design is concerned with how things are going to work and with detailing
the look and feel of the product. Physical design is about structuring interactions into
logical sequences and about clarifying and presenting the allocation of functions and
knowledge between people and devices. The distinction between conceptual and physi­
cal design is very important. The conceptual design relates to the overall purpose of
the whole interactive system. Between the people and the technologies there has to
be enough knowledge and ability to achieve the purpose. Physical design is concerned
with taking this abstract representation and translating it into concrete designs. On one
side this means requirements for hardware and software and on the other it defines the
knowledge required by people and the tasks and activities that people will have to do.
There are three components to physical design: operational design, representational
design and design of interactions.
Operational design is concerned with specifying how everything works and how con­
tent is structured and stored. Taking a functional view of an activity means focusing on
processes and on the movement, or flow, of things through a system. Events are occur­
rences that cause, or trigger, some other functions to be undertaken. Sometimes these
arise from outside the system under consideration and sometimes they arise as a result
of doing something else. For example, some activity might be triggered on a particular
day or at a particular time; another might be triggered by the arrival of a person or

Chapter 2 discusses
mental models

Methods for modelling
are discussed in Chapter 9



Part I • Essentials of designing interactive systems


The Community



Professional Society
of W eb Designer

Fishy W eb Inc.


Project Team

D irecto r
O (

Need more


Com petitor





If only I had
O r m ore powerful

H TM L Co der


C u rren t


Fig u re 3 .2 Rich pictures of (a) a pub and (b) a Web design com pany
(Source: After Monk, A. and Howard, S. (1998) Methods & Tools: the rich picture: a tool for reasoning about work context,
pp.21-30. © 1998 ACM, Inc. Reprinted by permission)

Interactions, 5(2),

Chapter 3 • The process of human-centred interactive systems design

Representational design is concerned with fixing on colours, shapes, sizes and infor­
mation layout. It is concerned with style and aesthetics and is particularly important for
issues such as the attitudes and feelings of people, but also for the efficient retrieval of
Style concerns the overall ‘look and feel’ of the system. Does it appear old and ‘clunky’
or is it slick, smooth and modern? What mood and feelings does the design engender?
For example, most Microsoft products engender an ‘office’ and ‘work’ mood, serious
rather than playful. Many other systems aim to make the interaction engaging, some
aim to make it challenging and others entertaining. In multimedia and games applica­
tions this is particularly important.
Interaction design, in this context, is concerned with the allocation of functions to
human agency or to technology and with the structuring and sequencing of the inter­
actions. Allocation of functions has a significant impact on how easy and enjoyable a
system is to use. Designers create tasks for people by the way they allocate functions.
For example, consider the activity of making a phone call. Conceptually speaking,
certain functions are necessary: indicate a desire to make a phone call, connect to the
network, enter the phone number, make connection. Years ago a telephone exchange
was staffed by people and it was these people who made connections by physically put­
ting wires into connectors. In the days of wired phones, picking up the receiver indicated
the desire to make a call, the full number had to be dialled in and then the telephone
exchange would automatically make the connections. Nowadays a person just has to
press the connect button on a cellular phone, choose someone’s name from the phone’s
address book and the technology does the rest.
Recall the activity-technology cycle (see Chapter 2). The allocation of knowledge
and activities between people and technologies is a significant part of how experiences
change over time.

Challenge 3.1
Find a colleague and discuss the activity of watching pre-recorded films on TV. Focus
on the way the allocation of function changes with the technology such as VCR, DVD
and PVR (personal video recorder). How has it changed now that on-line films are easily
available on your TV or PC?


See Section 12.5 on
inform ation design


Designs need to be visualized both to help designers clarify their own ideas and to ena­
ble people to evaluate them. Envisionment is concerned with finding appropriate media
in which to render design ideas. The medium needs to be appropriate for the stage of
the process, the audience, the resources available and the questions that the designer is
trying to answer.
There are many techniques for envisionment, but they include any way in which
abstract ideas can be brought to life. Sketches ‘on the back of an envelope’, fully function­
ing prototypes and cardboard mock-ups are just some of the methods used. Scenarios,
sometimes represented in pictorial form as storyboards, are an essential part of proto­
typing and envisionment. They provide a way of working through a design idea so that
the key issues stand out. Scenarios are discussed below.

Evaluation is tightly coupled with envisionment because the nature of the representa­
tion used will affect what can be evaluated. The evaluation criteria will also depend on
who is able to use the representation. Any of the other design activities will be followed

Chapter 8 presents
techniques for envisionment


Part I • Essentials of designing interactive systems

Chapter 10 provides
detail on evaluation

by an evaluation. Sometimes this is simply the designer checking through to make sure
something is complete and correct. It could be a list of requirements or a high-level
design brief that is sent to a client, an abstract conceptual model that is discussed with
a colleague, or a formal evaluation of a functional prototype by the future system users.
Techniques for evaluation are many and various, depending once again on the circumstances. Expressing the design ideas in terms of a concrete scenario that people
have to work their way through can be very effective. The important thing to keep in
mind is that the technique used must be appropriate for the nature of the representa­
tion, the questions being asked and the people involved in the evaluation.

Challenge 3.2
If you were to have a new room built onto your house - or have a room converted from
one use to another - consider the processes that you would have to go through, starting

• A conceptual design
A physical design
• Some requirements
• A prototype or other envisioned solution.

- ........................................-


...................................... ............... ................................................. J


-> Chapter 9 provides a
number of semi-formal

Figure 3.1 does not include the implementation or production of the design (nor all
the planning and management stages of a project). But, of course, ultimately things
have to be engineered and software has to be written and tested. Databases have to be
designed and populated and programs have to be validated. The whole system needs
to be checked to ensure that it meets the requirements until finally the system can be
formally ‘launched’ and signed off as finished. Since this book is primarily about design,
we do not spend a lot of time on issues of implementation, but they can account for
a significant portion of total development costs. Clients will often want extra features
when they see a system nearing completion, but these will have to be costed and paid
for. On the other hand, the developers need to ensure that their system really does meet
the specification and does not contain any ‘bugs’.
If interactive systems designers were architects they would have well-understood
methods and conventions for specifying the results of the design process. They would
produce various blueprints from different elevations and engineering specifications for
particular aspects of the design. In interactive systems design there are a variety of for­
mal, semi-formal and informal methods of specification. The best known of the formal
methods is the Unified Modeling Language (UML) (Pender, 2003).

Agile development
O ver the past few years there has been a m ove aw ay from large softw are engineer­
ing approaches to the developm ent of interactive systems towards 'agile' developm ent
methods. These are designed to produce effective systems o f high quality that are fit for
purpose, but w ithout the huge overhead associated w ith the planning and docum enta­
tion o f a large IT (inform ation technology) project.

Chapter 3 • The process of human-centred interactive systems design

There are a num ber o f com peting m ethods, but probably the best known com es
from DSDM , a not-for-profit consortium of softw are developm ent com panies. T h e ir
system , called Atern, is fu lly docum ented, show ing how softw are can be developed
in small teams. There is still plenty of debate about how w ell these methods, such as
extrem e programming (Beck and Andres, 2004), fit in with hum an-centred approaches,
but m any of the m ethods do prom ote participation between developers and stake­
holders. In particular, O bendorf and Finck (2008) describe a method bringing together
agile methods and scenario-based design.

3.2 Developing personas and scenarios
In order to guide the design process, designers need to think about the PACT elements
(introduced in Chapter 2). The people who will use the system are represented by perso­
nas: profiles of the different types, or archetypes, of people the designer is designing for.
Activities and the contexts in which they will occur are envisioned through scenarios of
use. Different concrete scenarios can be used to envision how different technologies could
function to achieve the overall purpose of the system. Personas and scenarios are devel­
oped through the understanding process, using any of a wide range of methods (discussed
in Chapter 7), and through undertaking a PACT analysis. Almost inevitably, personas and
scenarios evolve together as thinking about people involves thinking about what they want
to do, and thinking about activities involves thinking about who will be undertaking them!

Personas are concrete representations of the different types of people that the system
or service is being designed for. Personas should have a name, some background and,
importantly, some goals and aspirations. Alan Cooper introduced the idea of personas in
the late 1990s (Cooper, 1999) and they have gained rapid acceptance as a way of captur­
ing knowledge about the people the system or service is targeted at. In the latest edition
of his book (Cooper et al., 2007), he links personas very closely with his ideas of goaldirected design. Personas want to be able to do things using your system. They want to
achieve their aims, they want to undertake meaningful activities using the system that
the designer will produce. Designers need to recognize that they are not designing for
themselves. Designers create personas so that they can envisage whom they are design­
ing for. They create personas so that they can put themselves in other people’s shoes.
As any new system is likely to be used by different types of people, it is important to
develop several different personas. For example, in designing a website for people inter­
ested in the author Robert Louis Stevenson (described in more detail in Chapter 14),
we developed personas for a school teacher in Germany, a university lecturer from the
UK, a child in Africa and a Stevenson enthusiast from the USA. Such a diverse group of
people have very different goals and aspirations, and differ in all the ways - physically,
psychologically and in terms of the usage they would make of the site (see Chapter 2).

Scenarios are stories about people undertaking activities in contexts using technolo­
gies. They appear in a variety of forms throughout interactive systems design and are a
key component of many approaches to design.



Part I • Essentials of designing interactive systems

Scenarios have been used in software engineering, interactive systems design and
hum an-com puter interaction work for many years. More recently, scenario-based
design has emerged as an important approach to the design of interactive systems in the
twenty-first century (Alexander and Maiden, 2004).
One of the main proponents of scenario-based design is John Carroll, and his book
Making Use (2000) remains an excellent introduction to the philosophy underlying the
approach. In it he illustrates how scenarios are used to deal with the inherent difficulty
of doing design. Drawing on the activity-technology cycle (Figure 2.1) to show the posi­
tion in product development, he argues that scenarios are effective at dealing with five
key problems of design (Figure 3.3):
• The external factors that constrain design such as time constraints, lack of resources,
having to fit in with existing designs and so on.
• Design moves have many effects and create many possibilities, i.e. a single design
decision can have an impact in many areas and these need to be explored and

Design Moves Have Many Effects
Fig u re 3 .3 C hallenges and ap p ro ach es in scenario-based design
(Source: After John M. Carroll. Making Use: Scenario-based Design of Human-Computer Interactions. Fig. 3.2, p. 69 © 2000 Massachusetts Institute of
Technology, by permission of the MIT Press)

Chapter 3 • The process of human-centred interactive systems design

• How scientific knowledge and generic solutions lag behind specific situations. This
point concerns generalities. In other design disciplines, general design solutions to
general design problems have evolved over the years. In interactive systems design
this does not happen because the technology changes as soon as, or even before, gen­
eral solutions have been discovered.
• The importance of reflection and action in design.
• The slippery nature of design problems.
Our scenario-based design method is presented in the next section. Below are a few
examples of how we have used personas and scenarios in a recent project. Some are
quite detailed, others are single snapshots of interactions used to explore design options.

Example: Companions
W e have recently been looking at a novel form of interaction that goes under the title o f'co m ­
panions'. Com panions are seen as an intelligent, personalized, m ultim odal interface to the
Internet. Com panions know their 'owners' and adapt the interaction to personalized interests,
preferences and em otional state. In investigating the com panions concept w e have d evel­
oped a num ber o f persons and scenarios.
A health and fitness com panion (H FC), for example, would help provide advice and com ­
panionship for people in the dom ain o f health and fitness. W e explored the idea in a two-day
workshop attended by a num ber o f the project partners. During and subsequent to this w ork­
shop, three personas w ere developed to explore the various needs of people with differing
lifestyles, levels o f fitness and exercise regimes. These are shown in Figures 3.4, 3.5 and 3.6.
One central them e of the explorations concerned the m otivational approaches that would
be suitable for different scenarios and personas. The Sandy persona (Figure 3.4), fo r exam ­
ple, w ould need m ore encouragem ent and persuasion to exercise than the M ari persona
(Figure 3.5), perhaps by preventing a recorded television programme from being shown until
training is com pleted. A nother aspect, concerning social networking, was explored through
the Bjorn persona (Figure 3.6). Thus the personas w ere developed to reflect particular design
issues and values. The w hole issue of persuasion technologies is a difficult one fo r interaction

B. Fogg introduced the idea o f persuasion technologies, or 'captology' as he term s it,
in the late 1990s. It is a controversial idea. The basic aim o f captology is to persuade
people to do things they o therw ise w ould not do. At first sight this looks som ew hat
im m oral. W ho are w e, as designers, to persuade people to do som ething they don't
w an t to do? However, w e can see exam ples, such as the Sandy persona, w h ere per­
suading him to exercise is for his own good. W e also need to persuade people to take
precautions if things are dangerous. I am quite happy that a software system persuaded
me to save my w ork before the system crashed (on the other hand, w hy did the system
not ju st save it for me?). Persuasion is 'a non-coercive attem pt to change attitudes or
behaviors o f people' (Fogg e t al. 2007). However, if this is persuading me to buy som e­
thing that I cannot afford, then it is not good at all, w hether it is non-coercive o r not.
This is an area of HCI w here ethics and values must be taken seriously.

.................... -..-________ _______________________________ __ J
In another exploration w e looked at the concept of a com panion to deal with digital photos.
Such a com panion would be functional in helping organize, edit and share photos, but would
also be a conversational partner. W e envisaged a com panion that could discuss photos with
its ow ner and perhaps rem inisce about events and people.



Pari I • Essentials of designing interactive systems


age 46
drives a lot
drinks and eats too much
recently divorced
children in early 20s

- had recent health scare (suspected heart attack which was actually angina)
- kids have bought him a HFC
1. We meet Sandy in a hospital room, he's being visited by his kids.
2. They are worried about his health, he does little exercise and since his w ife left him his diet has become
3. They give him a HFC (w hat is this?!) which w ill combine w ith his current home system. They explain that
it's intended to help raise his general level of fitness, m onitor his health and set and maintain a healthy
balanced diet.
4. They all leave the hospital and Sandy starts the configuration.
5. Being ex-army Sandy decides that a tough-love drill instructor personality would suit him best (he's on
board w ith the fact that he needs to get healthy), so he selects Alf, a no-nonsense archetype companion
6. He opens his exercise regime to be accessible by his children, on th eir request, as he feels this w ill be an
added incentive fo r him to exercise.
7. Configuration involved biometrics such as w eight, height, etc., allowing A lf to suggest appropriate training
and diet.
8. It's aim is to understand w hether the ow ner is in bad condition needing to get better, w anting to
m aintain current health or aim fo r high performance.
9. A lf reprimands bad behaviour (such as buying unhealthy food), nags w hen he doesn't exercise, but offers
positive m otivation when he does.

Figure 3.4 The Sandy persona for HFC scenario


age 23
aerobics instructor
training seriously for first m arathon
her usual training partner has moved aw ay
she leads a w ild social life and tends to burn the candle at both ends
she's got a targeted schedule
companion is very proactive in pace making and m otivation

1. She's set up a long-term schedule w ith her HFC to enable her to run \
marathon in under 4 hours.
2. This includes targ et goals such as w h at tim es she should be running li
distances by which stage of the regime.
3. The HFC adapts to maintain the regime w hen Mari's social circumstance impacts her ability to train.
4. If she runs too fa r or too fast the companion w ill advise th at this may have a negative impact on her
training and may result in potential injury.
5. Explicit instructions in real tim e run ('ok, now w e're gonna push hard fo r 2 m inutes....ok, w ell done, let's
take it easy for the next 5 ....etc.').
6. The HFC has access to her social schedule (through social com panion?) and suggests going to a party the
night before a long run may not be a great idea.
7. A t the actual m arathon her HFC becomes a motivating force and gives her real-time advice (eg, 'there's a
hill coming up, pace yourself', it knows this from a run plug-in she bought fo r the HFC).

Figure 3 .5 The M ari persona for HFC scenario

Chapter 3 • The process of human-centred interactive systems design


Age 32
Office w o rker (ad account manager)
No children, lives alone
Dog died (used to w alk it for exercise)


S tartin g to pu t on w e ig h t
Used to p lay fo o tb a ll a t university, m uch less active n o w
A c tiv e social life

- 'I w an t to stay fit, but on my own tim e and fitting in to my own schedule'
1. Home from w ork, he was m eant to go out the previous evening but got invited out to a dinner party
instead. This evening is now free, so he decides to go fo r a run.
2. He's in his living room and sets up fo r his run. This involves:
- ro u te choice
- exercise level, eg easy jo g or hard run (specific pacing fe e d b a c k choice, eg w ith in PB)

- music choice
- disturbability status (eg, open to contact/running partner)
- w eather
- (warm up/stretching?)
3. He gets changed and leaves the house, the handover is transparent from living room companion to
mobile device-based companion and is aw are of all Bjorn's choices regarding run setup.
4. Just as he's about to begin, the sun breaks through the clouds and Bjorn decides he'd rather go for a
longer run than initially selected in his living room; this change must be facilitated through his mobile
companion device. Selective rather than creative process (eg, chose run three on route 2).
5. He starts running hard.
6. Asked w hether he's warm ed up as he's running above a warm -up rate.
7. He slows down to a more gentle jog and reaches his start point.
8. A touch of the device indicates he's starting his run.
9. M usic begins.

10. Pace-setting tactile feedback begins.
11. M idway through run he's inform ed that Julie is also running in the woods and has set her HFC at open to
running partners (this is a closed list of the pre-set social netw ork that Bjorn belongs to).
12. He slows down and runs on the spot and sends her a greeting, asking if she'd like to join him; she says yes.
13. She catches up and the companion autom atically reconfigures his pacing settings to match hers.
14. A fter a circuit they part ways and Bjorn heads home.
15. On entering the house Bjorn warm s down and stretches which induces a brief summary on his mobile
device w hilst the detailed data from his run is transparently transferred to his home netw ork.
16. He w alks into the kitchen to grab a glass of w ater and plan w h at to make fo r dinner. His home
companion notes that he w en t for a long run today so he must be hungry, and suggests some recipes
based on w h at he has in his fridge: 'how about the steak, it goes out of date tom orrow '. Nothing takes
his fancy so he asks the companion to search online w hilst he has a shower. Takes shower, comes down
and is presented w ith some new recipes and the fact th at Julie called and asked him fo r a drink that
17. A t a later tim e he asks fo r an overview o f his past three months' exercise. His companion notes that his
heart rate is recovering quicker which suggests he's getting fitter, but for the past tw o weeks he's not
been running fo r as long.

Figure 3.6 The Bjorn persona for HFC scenario

Figure 3.7 illustrates a scenario in w hich a person has a large collection of photographs
and wishes to search for a specific image from a recent trip. One feature of this scenario was
to explore different m odalities for the com panion. The interaction em ploys both speech and
touch depending on the activity being undertaken. For example, it is much quicker to specify
specific search parameters through speech than by typing or clicking a series of check boxes
(part 2 in the scenario). However, w hen it com es to flicking through the search-generated
group or applying certain other editorial functional tasks such as scaling and cropping, touch



Part I • Essentials of designing interactive systems

1. The user is moving from a standard view of
their photos to a search mode. This is a voice
driven function.

OK, I need to find
the perfect picture to
email. Open search.

2. Here the user narrows down the field by
establishing a search parameter again by
voice. Note that the user could search for any
metadata parameter or combination of
parameters that the system has established.
Indeed the system could proactively suggest
additional ones.

3. Having used voice to establish the smaller
field, the user now applies touch to quickly
flick through the pictures. Additional touch
functionality could include scaling, cropping
or editing.

4. Having found the photo they w an t to send,
the user now combines speech w ith touch to
indicate that the gesture o f flicking to the
left means email th at specific image to the
user's uncle.

Figure 3.7 An scenario of multimodal interaction with a photo companion

Show me all my
photos from my trip
to Rome.

' Hmm, there's a few
here, goodjob I can flick

through quickly!

Aha, that's perfect!
Send this to my unde


Chapter 3 • The process of human-centred interactive systems design

becomes the more natural interaction. For example, it's quicker to drag a finger back and forth
to resize an image in a serendipitous or haphazard fashion than it is to say, 'Make that image a
little bigger. . . bit bigger. . . bit bigger. . . no, that's too big. . . bit smaller. . . too small' and so
on. However, for specific categorial edits speech may be best, for example 'Make this image 4
by 6 inches and print'. The true power of the interaction experience comes from the consid­
ered use of both in conjunction.
In another scenario we were looking at environmental influence on the interaction. For
example, Figure 3.8 shows the potential for moving between displays. Small displays (e.g.
digital photoframes) have a more limited touch capability than a larger display (in the case
of Figure 3.8 an interactive coffee table). Figure 3.9 illustrates a further option, namely that
of using a display that is simply too far from the person to be touched. This in many ways
most fairly reflects the current living-room environment. In such a situation physical gesture
becomes an appropriate option, either by using one's hands or by wielding an object, such as
is used in the Nintendo Wii games console. This allows for parameters such as speed, direc­
tion and shape of movement.

Figure 3.8 An example of a multimodal interaction moving between displays from a digital
photoframe to a smart coffee table



Part I

Essentials of designing interactive systems

Figure 3.9 An example of a
gesture-based multimodal
interaction with a remote

3.3 Using scenarios throughout design
Scenarios (and their associated personas) are a core technique for interactive systems
design. They are useful in understanding, envisioning, evaluation, and both concep­
tual and physical design: the four key stages of interactive system design (Figure 3.1).
We distinguish four different types of scenario: stories, conceptual scenarios, concrete
scenarios and use cases. Stories are the real-world experiences of people. Conceptual
scenarios are more abstract descriptions in which some details have been stripped away.
Concrete scenarios are generated from abstract scenarios by adding specific design
decisions and technologies and, once completed, these can be represented as use cases.
Use cases are formal descriptions that can be given to programmers. At different stages
of the design process, scenarios are helpful in understanding current practice and any
problems or difficulties that people may be having, in generating and testing ideas, in
documenting and communicating ideas to others and in evaluating designs.
The place of the different types of scenario and the processes and products of the
design process are illustrated in Figure 3.10. The lines joining the types of scenario indi­
cate the relationships between them. Many stories will be represented by a few con­
ceptual scenarios. However, each conceptual scenario may generate many concrete
scenarios. Several concrete scenarios will be represented by a single use case. The dif­
ference between these types is elaborated below.
Figure 3.10 also illustrates three critical processes involved in design and how they
interact with the different scenario types. Designers abstract from the details of stories
to arrive at conceptual scenarios. They specify design constraints on conceptual scenar­
ios to arrive at concrete scenarios. Finally they formalize the design ideas as use cases.

Chapter 7 discusses
techniques for getting stories

Stories are the real-world experiences, ideas, anecdotes and knowledge of people. These
may be captured in any form and comprise small snippets of activities and the contexts in
which they occur. This could include videos of people engaged in an activity, diary entries,
photographs, documents, the results of observations and interviews and so on. People’s
stories are rich in context. Stories also capture many seemingly trivial details that are usu­
ally left out if people are asked to provide more formal representations of what they do.

Chapter 3 • The process of human-centred interactive systems design

Here is a story from someone describing what happened last time he made an appointment
to see his local doctor.
7 needed to make an appointment for Kirsty, my little one. It wasn't urgent - she had been
having a lot of bad earache every time she had a cold - but I did want to see Dr Fox since she's
so good with the children. And of course ideally it had to be when Kirsty was out of school
and I could take time off work. I rang the surgery and the receptionist told me that the next
appointment for Dr Fox was the next Tuesday afternoon. That was no good since Tuesday is
one of my really busy days, so I asked when the next one was. The receptionist said Thursday
morning. That meant making Kirsty late for school but I agreed because they sounded very
busy - the other phone kept ringing in the background - and I was in a hurry myself. It was
difficult to suggest a better time without knowing which appointments were still free.'

Conceptual scenarios
Conceptual scenarios are more abstract than stories. Much of the context is stripped
away during the process of abstraction (see Box 3.4) and similar stories are combined.
Conceptual scenarios are particularly useful for generating design ideas and for under­
standing the requirements of the system.

Once the designer has accumulated a collection of stories, common elements will start to
emerge. In this case a number of stories such as the one above result in the conceptual sce­
nario below, describing some requirements for a computerized appointments system.
Booking an appointment
People with any degree of basic computer skills will be able to contact the doctors' surgery
at any time via the Internet and see the times which are free for each doctor. They can
book a time and receive confirmation of the appointment.



Part I • Essentials of designing interactive systems

As you can see, at this stage, there is little or no specification of precise technologies
or how the functions will be provided. The scenario could be made more abstract by
not specifying that the Internet should be used or more concrete (that is, less abstract)
by specifying that the booking should be made from a computer rather than a mobile
phone. Finding an appropriate level of abstraction at which to describe things for a
given purpose is a key skill of the designer.

The process of abstraction is one of classification and aggregation: moving from the
details of specific people undertaking specific activities in a specific context using a par­
ticular piece of technology to a more general description that still manages to catch the
essence of the activity.
Aggregation is the process of treating a whole thing as a single entity rather than
looking at the components of something. In most domains, for example, one would
aggregate a screen, processor, disk drive, keyboard and mouse and treat this as a single
thing - a computer - rather than focusing on the components. However, in another
situation one of the components - processor speed, or disk size, say - may prove to be
critical and so it would be better to have two aggregations: fast computers and slow
computers, say.
Classification is the process of recognizing that things can be collected together, so
that dealing with the class of things is simpler (more abstract) than dealing with the
individual things. There are no set ways to classify things, so the analyst has to work with
the stories that have been gathered and with the people themselves to decide which
things belong together and why.
Between them, aggregation and classification produce abstractions. Of course, there
are different degrees of abstraction and it is one of the skills of a designer to settle upon
an appropriate level. The most abstract level is to treat everything simply as a 'thing' and
every activity as 'doing something', but such an abstract representation is not usually
very useful.

Concrete scenarios
Each conceptual scenario may generate lots of concrete scenarios. When designers
are working on a particular problem or issue they will often identify some feature that
applies only under certain circumstances. At this point they may develop a more spe­
cific elaboration of the scenario and link it to the original. Thus one reasonably abstract
scenario may spawn several more concrete elaborations which are useful for exploring
particular issues. Notes that draw attention to possible design features and problems
can be added to scenarios.
Concrete scenarios also begin to dictate a particular interface design and a particular
allocation of functions between people and devices. Concrete scenarios are particularly
useful for prototyping and envisioning design ideas and for evaluation because they
are more prescriptive about some aspects of the technology. However, there is not a
clean break between conceptual and concrete scenarios. The more specific the scenario
is about some aspects, the more concrete it is.

Chapter 3 • The process of human-centred interactive systems design

In this ex a m p le, d e c isio n s have n o w b een taken c o n c e rn in g d ro p -d o w n m en u s, th e fact that
th e next tw o w eeks' d e ta ils a re to b e sh o w n , an d so o n . H o w ever, th e n o tes fo llo w in g th e s c e ­
n ario sh o w that th e re a re m a n y d esign d e c isio n s still to b e taken.

Booking an appointment/01
A ndy Dalreach needs a doctor's appointm ent fo r his young daughter Kirsty in the next
week or so. The appointm ent needs to be outside school-tim e and Andy's core working
hours, and ideally w ith Dr Fox, w h o is the children's specialist. A ndy uses a PC and the
Internet at w ork, so has no difficulty in running up the appointm ents booking system. He
logs in [1] and from a series of drop-down boxes, chooses to have free tim es for Dr Fox
[2] displayed for the next two weeks [the scenario would continue to describe how Andy
books the appointm ent and receives confirm ation].

Notes to booking an appointment/01
1 Is logging in necessary? Probably, to discourage bogus access to the system, but check
with the surgery.

Free times can be organized by doctor, by tim e of day, or by next available tim e. Drop­
down boxes will save screen space but may present problems for less experienced users
or those with poor eyesight.

Use cases
A use case describes the interaction between people (or other ‘actors’) and devices. It
is a case of how the system is used and hence needs to describe what people do and
what the system does. Each use case covers many slight variations in circumstances many concrete scenarios. The lines in Figure 3.10 indicate how many concrete scenarios
result, after the process of specification and coding, in a few use cases.
Before use cases can be specified, tasks and functions have to be allocated to humans
or to the device. The specification of use cases both informs and is informed by the task/
function allocation process. This is the interaction design part of physical design.
Finally, all the design issues will be resolved and the set of concrete scenarios is then
used as the basis of the design. A set of use cases can be produced which specifies the
complete functionality of the system and the interactions that will occur. There are a
number of different ways of representing use cases - from very abstract diagrams to
detailed ‘pseudo code’. Figure 3.11 shows the ‘booking an appointment’ use case in a
typical format.

To make an appointment:
G o to doctors’ home page
Enter username and password





appointment k

Figure 3.11 Use case for booking an appointment

Select appointments for specific doctor
Brow se available dates
Select suitable date and time
Enter patient’s name
C lick O K

See also Chapter 11 on
task analysis



Part I • Essentials of designing interactive systems

Use cases
Despite the fact that use cases have been a core element of software engineering meth­
ods since the late 1980s, the concept remains elusive and different authors define a
use case in different ways. In a section called 'use cases undefined', Constantine and
Lockwood (2001) rage against the lack of clear definition for such a critical term. The
definition used in the Unified Modeling Language (UML) - an attempt to provide com­
monly agreed specification concepts and notation for software engineering - is too
lengthy and obscure to repeat here. Constantine and Lockwood also point out that how
the use case is specified - in a sort of pseudo programming code as we have done, or
simply using the diagrammatic ellipse and named role as some do, or otherwise - also
varies considerably between authors and methods.
It is also the case that use cases are used at different levels of abstraction. Constantine
and Lockwood's 'essential use cases' are similar to the conceptual scenarios described
here and there are others who base a whole design method on use case modelling. We
reserve the term 'use case' for describing an implementable system, i.e. enough inter­
face features have been specified, and the allocation of functions between people and
the system has been completed, so that the use case describes a coherent sequence of
actions between an actor and a system. The term 'actor' is used here because some­
times we need to specify use cases between one part of the system (a 'system actor")
and another, but usually the actor is a person.

Challenge 3.3
Find a vending machine or other relatively simple device and observe people using it.
Write down their stories. Produce one or more conceptual scenarios from the stories.

3.4 A scenario-based design method
The use of the different types of scenario throughout design can be formalized into a
scenario-based design method. This is illustrated in Figure 3.12 with, once again, prod­
ucts of the design process shown as boxes and processes shown as clouds. Besides the
four different types of scenario, four other artefacts are produced during the design
process: requirements/problems, scenario corpus, object model and design language.
The specification of a system is the combination of all the different products produced
during the development process.
Each of the main processes - understanding, envisionment, evaluation and design is the subject of a chapter in the next part of the book. An important thing to notice
is the relationship between specifying design constraints and the use of scenarios. For
envisionment and most evaluation, the scenarios have to be made more concrete. This
means imposing design constraints. However, this does not mean that the designer
needs to design a new physical, concrete scenario each time he or she wants to envision
a possible design. It may be that designers imagine a scenario with particular design
constraints imposed and this helps them evaluate the design. This sort of ‘what if?’ gen­
eration and evaluation of concrete scenarios is a common and key aspect of design.

Chapter 3 • The process of human-centred interactive systems design



Figure 3.12 Overall scenario-based design method

The key products that have not been discussed so far are: requirements and problems;
scenario corpus; conceptual model; and design language. These are briefly introduced
below for completeness, but a full understanding will require more in depth study.

Further details are
given in Chapters 7-10.

Requirements and problems

In the gathering of people’s stories and during the analysis and abstraction process,
various issues and difficulties will come to light. These help the analyst/designer to
establish a list of requirements - qualities or functions that any new product or system
should have. For example, in the HFC example, the companion had to be available both
at home and when exercising. It needed information about routes and personal pref­
erences. The requirements and problems product is a prioritized list of issues that the
system to be designed needs to accommodate.
Scenario corpus

In our approach we seek to develop a representative and carefully thought-through set,
or corpus, of scenarios. Having undertaken some analysis activities designers will have
gathered a wide range of user stories. Some of these will be very general and some will

-> See Chapter 7 on
understanding for



Part I • Essentials of designing interactive systems

be quite specific. Some will be fairly simple, straightforward tasks; others will be more
vague. It is important at some point for the designer to pull these disparate experiences
together in order to get a high-level, abstract view of the main activities that the product
is to support. These conceptual scenarios will often still be grounded in a real exam­
ple; the trick is to find an example that shares characteristics with a number of other
The rationale for the development of a corpus of scenarios is to uncover the ‘dimen­
sions’ of the design situation and to demonstrate different aspects of those dimensions.
Dimensions include characteristics of the various domains within which the product
will operate (e.g. large and small domains, volatile or static domains, etc.), the vari­
ous media and data types that need to be accommodated and the characteristics of the
people who will be using the system. The corpus of scenarios needs to cover all the main
functions of the system and the events that trigger the functions. Different types of inter­
action need to be present along with any key usability issues. The dimensions include
different types of content and how that can be structured, issues of style and aesthetics.
A corpus of scenarios might consist of several scenarios depending on the complexity
The HIC case study is in of the domain. For example, in the HIC study we had eleven, and for an MP3 applicaChapter 6 tj o n (which is much more specific - just playing, sorting and organizing MP3 files) we
had five. The aim is to specify the scenarios at a level of abstraction that captures an
appropriate level of generality that will be useful across the range of characteristics that
is demonstrated within a domain.
Conceptual model

Conceptual modelling is
covered in Chapter 9

An object or data model results from the process of conceptual modelling, including
developing the scenarios and understanding the objects and actions that are evident
from the analysis of the scenario corpus. The conceptual model shows the main objects
in the system, their attributes and the relationships that exist between them. Conceptual
modelling is a very important part of interactive systems design that is often overlooked.
Having a clear, well-designed conceptual model will make it easier to design so that
people can develop a good, accurate mental model of the system. The conceptual model
will also form the basis of the information architecture of a system and of any metaphor
that is used in the design.

Design language

We return

to this in

Chapter 9

The design language produced consists of a set of standard patterns of interaction and
all the physical attributes of a design - the colours, shapes, icons and so on. These are
brought together with the conceptual actions and objects, and the ‘look and feel’ of the
design is completed. A ‘design language’ defines the key elements of the design (such as
the use of colour, style and types of buttons, sliders and other widgets, etc.) and some
principles and rules for putting them together. A consistent design language means that
people need learn only a limited number of design elements and then they can cope
with a large variety of different situations.

Challenge 3.4
Take a look at the operating system that you use on your computer and identify some key
elements of the design language that is used.

Chapter 3 • The process of human-centred interactive systems design


Documenting scenarios

Scenarios can become messy, so in order to control the scenarios a structure is needed.
We use the PACT framework (people, activities, contexts, technologies) to critique sce­
narios and to encourage designers to get a good description of the scenario. For each
scenario the designer lists the different people who are involved, the activities they are
undertaking, the contexts of those activities and the technologies that are being used.
We also structure scenario descriptions. Each scenario should be given an introduction.
The history and authorship can be recorded, along with a description of how the sce­
nario generalizes (across which domains) and the rationale for the scenario. Each para­
graph of each scenario should be numbered for ease of reference and endnotes included
where particular design issues are raised. Endnotes are particularly useful in document­
ing issues raised during the development of the scenario. They are a way of capturing
the claims being made about the scenarios (Rosson and Carroll, 2002). Examples of
relevant data and media should be collected.

Trade-offs and claims analysis
Rosson and Carroll (2002) describe an approach to scenario-based design in which sce­
narios are used throughout the design process and how they help designers to justify
the claims that they make about design issues. Design is characterized by trade-offs.
There is rarely a simple solution to a problem that solves all the issues. Usually the adop­
tion of one design will mean that something else cannot be achieved. Designers need
to document their design decisions so that the trade-offs can be evaluated. Scenarios
help by making the rationale for the design explicit. Designers can record the claims
that they make about their designs. Claims analysis is an important part of scenariobased design and is used in identifying problems or in thinking through possible future
designs (Rosson and Carroll, 2002). The process is simply to identify key features of a
scenario and to list good and bad aspects of the design. Rosson and Carroll use a tech­
nique of putting a '+' beside good features and a ' beside bad features. Claims analysis
makes the rationale behind a design explicit.
A similar method is to list the design questions, design options and criteria used to
make choices, the QOC method (MacLean et al„ 1991).

Challenge 3.5
Take a device or system that you have to hand - a mobile phone, a website, a vending
machine - and critique the design, focusing on the aspects that are central to its use.
Make a list of claims about the design.
- - - ...... ....................................................... ...................... -................................... .....................-............................................... -... J

When working in a large design team, it is useful to accompany scenarios with real data.
This means that different team members can share concrete examples and use these as
a focus of discussion. Another key feature of writing scenarios is to think hard about the
assumptions that are being made: to make assumptions explicit or deliberately avoid
making things explicit in order to provoke debate. In particular, the use of personas can
help to focus on specific issues. For example, an elderly woman with arthritis might be
one of the personas, thus foregrounding issues of access and the physically impaired
interacting with technology.

Chapter 2 describes PACT


Part I • Essentials of designing interactive systems

Finally, with scenarios it is important to provide a very rich context. The guiding
principles for scenario writing are people, activities, contexts and technologies.

Example: Scenario MP3/01 ‘How does that song go again?’

-* The HIC case study
is in Chapter 6

This example illustrates how scenarios can be structured and used to think about designs
and become part of a corpus. The context for this scenario was the development of a Home
Information Centre (HIC). The HIC was envisaged as a new type of information, communi­
cation and entertainment device that would look good in the home and, whilst providing
similar functions to a computer, would have a novel interface making it far more enjoyable
and natural to use.
In developing the MP3 player function for the HIC, we explored a number of different
scenarios, finally finishing with five that defined the MP3 function corpus. The example here
shows the scenario being used to explore requirements and concepts for the HIC. Notice that
whilst being quite abstract, it is concrete enough to bring design issues to the fore. Figure 3.13
shows a QOC claims analysis for this scenario.
T itle

'How does that song go again?'
Scenario type
Activity scenario
People = Anne, a single female, computer-literate. Works at home.
Activities = Searching for MP3 tracks.

The selected track
stays in the display
list, but is highlighted
to show it has been
‘activated’ and is ready
H o w to
w hen a
tra c k is
‘se le cte d ’

to have actions (e.g.
play) performed on it

Straightforward. Reduces the
need fo r more than one
Reduced screen clutter
No other display objects
required on screen to
indicate selection.

Another; separate
object displays the
track, indicating its
status as ‘selected and
ready to be played’

The user can infer from the
visual appearance the state
of the system. The item is
unambiguously selected and
is ready to have actions
performed on it.
Flexibility of screen use
The solution addresses the
issue of limited screen space
caused by competition from
other interface elements
from the same o r different

Figure 3.13 An exam ple of the QOC {questions, options, criteria) claim s method

Chapter 3 • The process of human-centred interactive systems design

Context = Apartment with office/study space where user works from home. HIC is in the
kitchen, which is adjacent to the study.
Technology = The HIC and a PC.
The substantive activity here is the use of the search function to find a specific MP3 track. The
use of different search parameters is described. The user interrogates the HIC using keyboard
input; future elaborations might deal with other modalities such as voice input.
PI. Anne is a freelance arts journalist who works mainly from home. She's writing a piece
for a national newspaper about singer-songwriters, and is irritated to find she can't remember
the lyrics of a particular well-known song she wants to quote in her article. She knows the
name of the singer and the song title, but beyond that, her memory is failing her.
P2. She leaves her desk, hoping a break and a cup of coffee will dispel the block. While in
the kitchen, she decides she'll check the HIC for new messages [1], While she is doing this, she
realizes the HIC's MP3 player [2] can help her out.
She remembers she has downloaded the song [3] she needs at some time in the past two
months or so, and knows it's still in the HIC's memory [4],
P3. She selects the 'play' function (Level 1 of the HIC's actions bar) [5], which takes her
down one level in the HIC interface, to where she can see 'MP3 search' [6]. She selects this
and the familiar Rolodex interface comes up, asking her to enter some search details. She can
search by entering an artist name, track title or music genre - these are all elements of an MP3
track's identity which the HIC can recognize. She is about to enter the artist's name, but real­
izes she has stored several of this singer's tracks in the HIC; to get a unique search result first
time, she enters the track name instead, using the keyboard [7],
P4. The HIC quickly finds the track and asks her [8] if she wants to play it now. She does, and
selects this option by touching the screen [9]. The MP3 controller appears on the screen, with
the selected track already loaded and ready to play.
P5. She touches the 'play' button and listens. She increases the volume [10]. The lyrics she
wants come back to her straight away - she can now go back to her desk. She leaves the HIC
on [11] (without thinking).
P6. Later on, she has finished her piece and e-mailed it to her editor. But she wants to hear
the song again, as it has sentimental memories for her. Fortunately, she has left the HIC on in
MP3 mode. All she needs to do is select 'replay' and the song plays again.
P7. She decides she has put in enough time at the computer for the day, and feels like
watching some TV. She chooses the TV device on the HIC and settles down to watch the early
evening news [12].
Notes to scenario MP3/01
1 Checking messages is peripheral to the MP3 domain, but it is interesting to consider how
MP3-related activities fit in with other domains of the HIC. Multiple screen objects will
soon start to compete with each other for screen space.
2 'MP3 player' is meant here in the general sense of the MP3 domain - that is, all the func­
tions relating to MP3.
3 How she has done this is not described here - but see scenario MP3/02 for a more
detailed account of this activity.
4 The question of how the HIC stores MP3 and other files is a significant one. One of the
popular features of the MP3 format is the ease with which files can be shuffled from one
platform to another; this will involve frequent use of saving, copying, deleting and other
functions. This may imply the need for some sort of'File Manager" function in the HIC (cf.
scenarios MP3/02, /03, /04).
5 The Actions Bar is now a well-established part of the HIC prototype. Here, Anne goes one
level down the HIC's navigation hierarchy to get to the MP3 domain, and her point of
entry is the 'play' icon, found on the Actions Bar. But there may be other points of entry
too - say, from a 'Favourites' menu or similar.



Parti • Essentials of designing interactive systems

6 The MP3 domain may be made up of different modules - a 'player” with functional con­
trols, a search function, track lists, and so on. Some or all of these may be present on
screen at onetime; this raises the question of what the 'default' configuration will be: only
the basic functional controls? All the different modules? And how will the user call these
up or dismiss them as required?
7 Consider other modalities too: handwritten using a stylus and pressure pad? Voice input?
8 How is the search result presented to Anne? It may be in the form of a list, with the results
containing the parameters she gave the HIC. The search may return several results, and
there should be a way for her to unambiguously select a track from a list. This could be
tricky unless the text is at a good size and spacing for touching on a screen - unless some
other selection method is used.
9 She is close to the screen - but could she select the option remotely too?
10 Perhaps the HIC could sample the level of background noise in the area, and adjust the
playback volume automatically.
11 Is there a screen saver?
12 What happens to the MP3 interface when the TV comes on? Presumably the whole of
the HIC's information space will be filled by the TV image. Other functions and controls
will need to be cleared from the screen (perhaps returning automatically when the TV is
turned off). Or they could be reduced greatly in size, and put onto a display bar on the
periphery of the screen. Perhaps there could be a 'bring to front' command (operated
remotely, or by voice?) to make other controls available while the TV was still active.

Cross-referencing scenario types
Another aspect of documentation that is useful is to cross-reference the stories to the
conceptual scenarios, through the concrete examples and finally to the use cases. A sim­
ple Web-based system can be developed, as illustrated in Figure 3.14.
Other researchers have suggested similar ideas that capture the multiple views nec­
essary to see how scenarios and claims work together to provide a rich understanding of
how a design finished as it did.


Scenario 99/01 - What shall we have for dinner?


T ype
E laboration
, Overview _



Activity Scenario
E 9 9 / 0 I I . E99/01-2. E 99/01-3. E99/01-4


Uses.s.m Ariull.nvj..older adnll uvr/hnuy.hcldp-ur.U user__________________

PI. Pia lives with her 8 year old son Patrick in a small town in rural Scotland, Kirkdean. She
teaches French at the local school, and although not originally from the area has become very
involved in local activities since moving there 3 years ago. Tonight after work the four other
committee members of the local amateur dramatic society Pia attends are coming round for a
meal to celebrate their success in securing a grant from the local government authority to put on
a summer open-air theatre festival.
P2. Pia’s 76 year old father David, who lives in London, is visiting! 11 for a few weeks. David
recently spent several days in hospital being treated for the worsening arthritis in his hands. Pia
invited him to stay in the hope that she can persuade him to make it a more permanent
arrangement, since she is worried that his limited movements in his hands will make life very
difficult on his own.
P3. It is 07:00. Pia had hoped to sort out arrangements for this evening’s meal before now.
However her son was unwell last night so she didn’t get time to do it when she planned. She
must now decide what she is cooking and ensure she has the necessary provisions while getting
re a d y to lea v e fo r w o rk at 0 8 1 S P l W h ile sh e m a k e s so m e to ast sh e a c tiv a te s th e H 1 C R 1 _______

Figure 3.14 The scenario w eb


1 -Catriona
M acaulay - 04MAY-09
What access
'rights' to the HIC
will visitors/guests
2 - Catriona
Macaulay *04­
M AY-09
Kitchen use o f the
HIC is likely to
take place while
the user is engaged
in a number o f
other activities, or
in the morning
( --------------;


i- ►

Chapter 3 • The process of human-centred interactive systems design

Summary and key points
The design of interactive systems is concerned with people, the activities they are under­
taking, the contexts of those activities and the technologies that are used. This chapter
has introduced the main elements of design - understanding, envisionment, design and
evaluation - and how scenario-based design and the development of personas can be
used to guide the designer. Scenarios and their different uses in this process have been
• Scenarios are stories about the interactions between people, activities, contexts and
• Scenarios offer an effective way of exploring and representing activities, enabling the
designer to generate ideas, consider solutions and communicate with others.
• Scenarios are used throughout the design process and, along with the requirements
and problems, conceptual design and design language can form part of the specifica­
tion of the system.

1 Find someone using some technology to do something and observe what
they do. Now write down the story associated with that activity. Abstract a
conceptual scenario from this one experience, by removing the contextual
detail and other details about the specific interface to the technology. Now
think of an alternative design for a device that would allow someone to
undertake a similar activity and generate a concrete scenario based on these
design constraints. Finally, specify this as a use case.

2 Develop a scenario corpus for people using a vending machine. Consider the
dimensions of the usage, the contexts for the interaction and the range of
people that you would want to consider.


................................................................................................................................................................ -

.... .... ................


- ........- ........................- ............................................................................................

Further reading
Cooper, A., Reiman, R. and Cronin, D. (2007) About Face 3: The Essentials of Interactive
Design. Wiley, Floboken, NJ. Cooper et al. give an insightful and enjoyable tour through some
of the worst aspects of interactive systems design and introduce their approach, which focuses on
developing personas and taking a goal-oriented approach to design.
Rosson, M.-B. and Carroll, J. (2012) Scenario-based design. In J.A.Jacko (ed.) The HumanComputer Interaction Handbook: Fundamentals, Evolving Technologies and Emerging
Applications, 3rd edn. CRC Press, Taylor and Francis, Boca Raton, FL.
Winograd, T. (ed.) (1996) Bringing Design to Software. ACM Press, New York. This book con­
tains a number of interesting articles from interactive systems designers and is essential reading
for all would-be interactive systems designers.



Part I • Essentials of designing interactive systems

Getting ahead
Interactions is an excellent journal focusing on interactive systems design.
Carroll, J.M. (ed.) (1995) Scenario-based Design. Wiley, New York.
Carroll, J.M. (2000) Making Use: Scenario-based Design of Human-Computer Interactions.
MIT Press, Cambridge, MA.
Rosson, M.-B. and Carroll, J. (2002) Usability Engineering. Morgan Kaufmann, San Francisco, CA.
John (Jack) Carroll has been hugely influential in the area of human-computer interaction
over many years and with his wife, Mary-Beth Rosson, has written extensively on scenariobased design. The first of his books is a collection of papers showing how the scenario con­
cept appears in a variety of guises throughout human-computer interaction and software
engineering. The second is compiled from many of his writings and presents a thoughtful
and coherent approach to developing systems using scenarios. It illustrates how scenarios
are appropriate in all the stages of systems development. The third is a practical design book.

There are some good white papers on Jared Spools' website, some of which cover personas.
The accompanying website has links to relevant websites. Go to

Comments on challenges

Challenge 3.1
When watching a movie on a VCR, the TV would often automatically select the appropriate TV
channel and the VCR would start playing automatically. Thus the function of 'start film' was allo­
cated to the device, and often the function of'select VCR channel' was allocated to the device. With
DVDs the human often has to select the appropriate channel and has to select 'start film', or 'play
movie', from a menu. So people now have extra tasks to perform. Moreover, the default option on
DVDs is often not 'play movie', so the person has to navigate to the appropriate option, giving them
even more tasks. PVRs are different again, requiring people to undertake several tasks to watch a
film. With huge numbers of films, clips and longer parts of films, YouTube requires people to under­
take much more searching and selecting. When allocating functions to people or to devices, think
hard about what tasks you are forcing people to undertake.

Challenge 3.2
A conceptual design would focus on the idea for the room. You may think it would be nice to have
a conservatory or a downstairs toilet and proceed from there. You would evaluate the idea, perhaps
by looking at some physical prototypes at a large store or at a friend's house. This might help to
define the requirements, such as the size of the conservatory, where you would locate it and so on.
Starting with a physical design, you might see something at a friend's or on television and this might
trigger the idea that it would be a nice thing to have. Once you have the concept, proceed as above.
Seeing a picture in a book is another example of an envisioned solution starting the process off. On
other occasions the process might be started by some requirements. You may feel that you need
a study, a new room for a baby, or somewhere to sit in the sun in the winter and it might be these
requirements that begin the process. Notice how, wherever the process starts from, the next step
will be some evaluation.

Chapter 3 • The process of human-centred interactive systems design

Challenge 3.3
A man wearing an overcoat and carrying a backpack came up to the machine and stared at it for
two or three minutes. Whilst he was doing this two younger men came up behind him and were
trying to look over his shoulder. Finally, he put his hand in his pocket and inserted some money. He
pressed two buttons, B and 7, and watched as a packet of crisps was deposited in the tray.
You can im a g in e a fe w m o re sto rie s su ch as th is, re su ltin g in a c o n c e p tu a l s c e n a rio a lo n g th e
lin es o f 'A p e rso n c o m e s u p to th e m a c h in e , stu d ie s th e in stru ctio n s an d w h a t is a v a ila b le , in serts
m o n ey, p resses tw o b u tto n s an d re trie ve s th e goods'.

Challenge 3.4
Key aspects of the design language are standard features of things such as windows and the differ­
ent types of windows (some that are resizable, some that are not, etc.). Other features include the
design of menus, dialogue boxes, alert boxes and so on. The colours are also consistent and chosen
to evoke different feelings in people.

Challenge 3.5
Of course, this will depend on the device you have chosen and on how you approach the critique.
The design principles (Chapter 4) are a good way to think about designs. A critique of a vending
machine, for example, might include the claims:

U sefu l fo r o u t-o f-h o u rs sales

X Limited selection of goods
/ Quick interaction
X Does not always give change
X Mis-operation results in lengthy and time-consuming complaints
/ High service costs.


Chapter 4












U sability




Usability has always been the central pursuit of human-computer
interaction (HCI). The original definition of usability is that systems
should be easy to use, easy to learn, flexible and should engender
a good attitude in people (Shackel, 1990). As the variety of people,

Introduction 77

4.2 Accessibility 77
4.3 Usability 81
4.4 Acceptability 84

4.5 Design principles 86
Summary and key points 90
Exercises 91
Further reading 91
W eb links 91
Com m ents on challenges 92

activities, contexts and technologies of interactive system design
has increased, so this definition, whilst still being valid, hides many
important issues. For example, accessibility is now a key design aim,
as is sustainability. The goals of usability are now primarily seen as
concerned with efficiency and effectiveness of systems.
After studying this chapter you should be able to:
• Understand the key issues and concepts of access
• Understand the principles underlying usability
• Understand the key issues of acceptability
• Understand the general principles of good interactive systems

Chapter 4 • Usability

4.1 Introduction
Good design cannot be summed up in a simple way and nor can the activities of the
interactive systems designer, particularly one who takes a human-centred approach
to design. One view might say, ‘The interactive systems designer aims to produce sys­
tems and products that are accessible, usable, socially and economically acceptable’.
Another view might say, ‘The interactive systems designer aims to produce systems
that are learnable, effective and accommodating’. A third view could be, ‘The aim of
the interactive systems designer is to balance the PACT elements with respect to a
domain’. All of these views are valid. In this chapter we explore these complemen­
tary views of good design. We also develop some high-level design principles that can
guide designers and be used to evaluate design ideas. Finally, we put these ideas into
practice by looking at some examples of good and bad design across different design
Accessibility concerns removing the barriers that would otherwise exclude some
people from using the system at all. Usability refers to the quality of the interaction in
terms of parameters such as time taken to perform tasks, number of errors made and
the time to become a competent user. Clearly a system must be accessible before it is
usable. A system may be assessed as highly usable according to some usability evalua­
tion criteria, but may still fail to be adopted or to satisfy people. Acceptability refers to
fitness for purpose in the context of use. It also covers personal preferences that contrib­
ute to users ‘taking to’ an artefact, or not.

4.2 Accessibility
Access to physical spaces for people with disabilities has long been an important
legal and ethical requirement and this is now becoming increasingly so for informa­
tion spaces. Legislation such as the UK’s Equality Act 2010 and Section 508 in the USA
now requires software to be accessible. The United Nations and the World Wide Web
Consortium (W3C) have declarations and guidelines on ensuring that everyone can get
access to information that is delivered through software technologies. With an increas­
ingly wide range of computer users and technologies, designers need to focus on the
demands their designs make on people’s abilities. Designers have to design for the
elderly and for children. Newell (1995) points out that the sorts of issues that face an
ordinary person in an extraordinary environment (such as under stress, time pressures,
etc.) are often similar to the issues that face a person with disabilities in an ordinary
People will be excluded from accessing interactive systems for any of a number of
• Physically people can be excluded because of inappropriate siting of equipment or
through input and output devices making excessive demands on their abilities. For
example, an ATM may be positioned too high for a person in a wheelchair to reach,
a mouse may be too big for a child’s hand or a mobile phone may be too fiddly for
someone with arthritis to use.
• Conceptually people may be excluded because they cannot understand complicated
instructions or obscure commands or they cannot form a clear mental model of the
• Economically people are excluded if they cannot afford some essential technology.



Part I • Essentials of designing interactive systems

• Cultural exclusion results from designers making inappropriate assumptions about
how people work and organize their lives. For example, using a metaphor based on
American football would exclude those who do not understand the game.
• Social exclusion can occur if equipment is unavailable at an appropriate time and
place or if people are not members of a particular social group and cannot under­
stand particular social mores or messages.
Overcoming these barriers to access is a key design consideration. Two main approaches
to designing for accessibility are ‘design for all’ and inclusive design. Design for all (also
known as universal design) goes beyond the design of interactive systems and applies
to all design endeavours. It is grounded in a certain philosophical approach to design
encapsulated by an international design community (see Box 4.1). Inclusive design is
based on four premises:

Aesthetics in interaction
design is discussed in
Ch ap ter


• Varying ability is not a special condition of the few but a common characteristic of
being human and we change physically and intellectually throughout our lives.
• If a design works well for people with disabilities, it works better for everyone.
• At any point in our lives, personal self-esteem, identity and well-being are deeply
affected by our ability to function in our physical surroundings with a sense of cornfort, independence and control.
• Usability and aesthetics are mutually compatible.

Principles of universal design*
Equitable use. The design does not disadvantage or stigmatize any group of users.
Flexibility in use. The design accommodates a wide range of individual preferences and
Simple, intuitive use. Use of the design is easy to understand, regardless of the user's
experience, knowledge, language skills, or current concentration level.
Perceptible information. The design communicates necessary information effectively to
the user, regardless of ambient conditions or the user's sensory abilities.
Tolerance for error. The design minimizes hazards and the adverse consequences of acci­
dental or unintended actions.
Low physical effort. The design can be used efficiently and comfortably, and with a mini­
mum of fatigue.
Size and space for approach and use. Appropriate size and space are provided for approach,
reach, manipulation, and use, regardless of the user's body size, posture, or mobility.
* Compiled by advocates of universal design, listed in alphabetical order: Bettye Rose Connell, Mike Jones, Ron
Mace, Jim Mueller, Abir Mullick, Elaine Ostroff, Jon Sanford, Ed Steinfeld, Molly Story, Gregg Vanderheiden.
© Centre for Universal Design, College of Design, North Carolina State University

iiii . i

i ■ iiiiiiiii . ~

- ~




. . n mir

i urn


Inclusive design is a more pragmatic approach that argues that there will often be
reasons (e.g. technical or financial) why total inclusion is unattainable. Benyon et al.
(2001) recommend undertaking an inclusivity analysis that ensures that inadvert­
ent exclusion will be minimized and common characteristics that cause exclusion and
which are relatively cheap to fix will be identified. Distinguishing between fixed and
changing user characteristics, they present a decision tree (see Figure 4.1). We all suf­
fer from disabilities from time to time (e.g. a broken arm) that affect our abilities to use
interactive systems.

Chapter 4 • Usability


in cid en ce

so lu tio n (s)

possible re co m m en d a tio n s

inclusion mandatory
inclusion mandatory
inclusion recommended
inclusion optional
inclusion mandatory
inclusion strongly recommended
inclusion recommended
inclusion optional

Figure 4.1 Decision tree for inclusivity analysis
(Source: after Benyon

e t a l.

(2001), Figure 2.3, p. 38)

As a way of ensuring an accessible system, designers should:
• include people with special needs in requirements analysis and testing of existing
• consider whether new features affect users with special needs (positively or nega­
tively) and note this in the specification;
• take account of guidelines - include evaluation against guidelines;
• include special needs users in usability testing and beta tests.
There are a number of assistive technologies, such as Web browsers that read Web
pages, and screen enlargers which allow people to set and move the area of focus. Voice
input is increasingly available not just for text entry but also as a substitute for mouse/
keyboard control, and keyboard filters can compensate for tremor, erratic motion
and slow response time. Indeed, there are many highly specialist methods for input
and output for people with various disabilities. For example, Majaranta et al. (2009)
describe a system for typing input through gazing at particular letters.
In the MS Windows operating system there is an Accessibility Option (under the con­
trol panel) that allows the setting of keyboard, sound, visual warnings and captions for
sounds. The display can be altered, including setting a high contrast, and mouse settings
can be adjusted. The Universal Access control panel on the Mac offers similar options
(Figure 4.2). A screen reader produces synthesized voice output for text displayed on
the computer screen, as well as for keystrokes entered on the keyboard. Voice-based
browsers use the same technology as screen reading software, but are designed specifi­
cally for Internet use (Figure 4.3).
Web accessibility is a particularly important area as many websites exclude people
who are not fit and able. The W4A conference and ACM’s SIGACCESS group contain
many specialist papers and discussions. Bobby is an automated tool that checks Web
pages for conformance to the W3C standards. However, in a study of university web­
sites, Kane et al. (2007) found serious accessibility problems, showing that there is still
some way to go before these issues are overcome.
To a large extent, design for all is just good design. The aim is to design to cater for
the widest range of human abilities. By considering access issues early in the design



Part I • Essentials of designing interactive systems

O O P ______
[ ■*


► I I Show All

Sticky Keys allows modifier keys to be set without having
to hold the key down.
O Enable Sticky Keys


Slow Keys adjusts the amount of time between when a key is
pressed and when it is activated.

G Enable Slow Keys


Mouse & Trackpad


r _________ _______


Full keyboard access and key repeat delay can be set or turned off in
Keyboard preferences:
Open Keyboard Preferences— [

0 Enable access for assistive devices
0 S h o w Accessibility status in menu bar

Figure 4.2 Options for accessibility keyboard settings

Figure 4.3 A choice of voices (OS X)

process, the overall design will be better for everyone. Stephanidis (2001) provides a
range of views on how this can be accomplished, from new computer ‘architectures’
that can accommodate different interfaces for different people, to better requirements
generation processes, consideration of alternative input and output devices and the
adoption of international standards.

Chapter 4 • Usability

Challenge 4.1
The UK government is considering introducing electronic access to a variety of social
benefits (such as unemployment benefit, housing benefit, etc.). What are some of the
access issues involved with this?

.......-.........- ............. - ........- - --------- .............. ............ :.................................................J

4.3 Usability
A system with a high degree of usability will have the following characteristics:
• It will be efficient in that people will be able to do things using an appropriate amount
of effort.
• It will be effective in that it contains the appropriate functions and information
content, organized in an appropriate manner.
• It will be easy to learn how to do things and remember how to do them after a
• It will be safe to operate in the variety of contexts in which it will be used.
• It will have high utility in that it does the things that people want to get done.
Achieving usability requires us to take a human-centred approach to design and to
adopt a design approach in which evaluation is central. Some early pioneers of usability,
Gould et al. (1987), developed the message kiosks for the 1984 Olympic Games. They
based their approach on three key principles that Gould and Lewis (1985) had evolved
over the previous three years. Their principles were:
• Early focus on users and tasks. Designers must first understand who the users will
be, in part by studying the nature of the expected work to be accomplished, and
in part by making users part of the design team through participative design or as
• Empirical measurement. Early in the development process, intended users’ reactions
to printed scenarios and user manuals should be observed and measured. Later on
they should actually use simulations and prototypes to carry out real work, and their
performance and reactions should be observed, recorded and analysed.
• Iterative design. When problems are found in user testing, as they will be, they must
be fixed. This means design must be iterative: there must be a cycle of design, test
and measure, and redesign, repeated as often as necessary. Empirical measurement
and iterative design are necessary because designers, no matter how good they are,
cannot get it right the first few times (Gould et al., 1987, p. 758).
As a result of their experiences with that project they added a fourth principle, inte­
grated usability:
All usability factors must evolve together, and responsibility for all aspects of usability
should be under one control.
(p. 766)

The development of the Olympic Message System (OMS) is described in detail in
Gould et al. (1987) and it still makes interesting reading in terms of the different types
of testing that were done, from written scenarios of use to ‘try-to-destroy-it’ tests!
However, these classic principles are not advocated by everyone. Cockton (2009), for
example, argues that designers need to understand the values that their designs are

See Section 3.1



Part I • Essentials of designing interactive systems

aiming at and that the sort of advice offered by Gould and Lewis (1985) is dangerous
and out of date. Whilst not going as far as that, we would certainly agree that designers
need to consider what worth their designs bring to the world!

Value Sensitive Design
Value Sensitive Design is a design approach that aims to account for human values in
a principled and comprehensive manner emphasizing the moral perspective, usability
and personal preferences. It focuses on three types of investigations.
1 Conceptual investigations concern philosophically informed analyses of the central
constructs and issues under investigation.
2 Empirical investigations focus on the human response to the technical artefact, and
on the larger social context in which the technology is situated.
3 Technical investigations focus on the design and performance of the technology
itself, involving both retrospective analyses of existing technologies and the design
of new technical mechanisms and systems.
Based on

PACT is covered in
Chapter 2

One way to look at usability is to see it as concerned with achieving a balance between
the four principal factors of human-centred interactive systems design, PACT:

Activities people want to undertake
Contexts in which the interaction takes place
Technologies (hardware and software).

The combinations of these elements are very different in, for example, a public kiosk, a
shared diary system, an airline cockpit or a mobile phone; and it is this wide variety that
makes achieving a balance so difficult. Designers must constantly evaluate different
combinations in order to reach this balance.
Figure 4.4 illustrates an important feature of human-computer interaction. There
are two relationships that need to be optimized. On the one hand there is the interaction

Figure 4.4 Usability aim s
to achieve a balance in
the PACT elements

Chapter 4 • Usability

between people and the technologies that they are using. This focuses on the user inter­
face. The other relationship is the interaction between the people and technologies con­
sidered as a whole (the people-technology system), the activities being undertaken,
and the contexts of those activities.
The idea of a people-technology system optimized for some activities is nicely
illustrated with an example from Erik Hollnagel (1997). He discusses the difference
between a person on a horse travelling across open countryside and a person in a car
travelling along a road. The combinations of technologies are balanced for the different
contexts of travelling; neither is better in all circumstances. It is important to remember
that the people-technology system may consist of many people and many devices work­
ing together to undertake some activities.

Challenge 4.2
Think of the activity of writing and all the various contexts in which we undertake this
activity. For example, you might be writing a report for a student assignment, writing a
postcard from a poolside chair on holiday, writing down some thoughts on a train, taking
notes in a lecture and so on. Now think about the different technologies that we use for
writing: ballpoint pens, felt-tipped pens, computers, palmtop devices and so on. Which
combinations are most usable in which circumstances? Why?

Don Norman (Norman, 1988) focuses on the interface between a person and the tech­
nology and on the difficulty of people having to translate their goals into the specific
actions required by a user interface. Norman’s characterization is as follows:
• People have goals - things they are trying to achieve in the world. But devices typi­
cally only deal with simple actions. This means that two ‘gulfs’ have to be bridged.
• The gulf of execution is concerned with translating goals into actions, and the gulf of
evaluation is concerned with deciding whether the actions were successful in moving
the person towards his or her goal.
• These gulfs have to be bridged both semantically (does the person understand what
to do and what has happened?) and physically (can the person physically or percep­
tually find out what to do or what has happened?).
A key issue for usability is that very often the technology gets in the way of people and
the activities they want to do. If we compare using an interactive device such as a remote
control to using a hammer or driving a car, we can see the issue more clearly. Very often
when using an interactive system we are conscious of the technology; we have to stop to
press the buttons; we are conscious of bridging the gulfs (Figure 4.5). When hammer­
ing or driving we focus on the activity, not the technology. The technology is ‘present to
hand’ (see Further thoughts box).

Figure 4.5 Bridging the gulfs
(Source: after Norman and Draper
(eds) (1986))



Part I • Essentials of designing interactive systems

Technological breakdown

---------------------------------------------------------------------------- j

<- Mental models are
discussed further in Chapter 2

When using a hammer, driving or writing with a pen we will usually focus on the
activity itself: we are hammering, driving or writing. It is only when something
happens to interfere with the smooth operation of these technologies that we
become aware of them. If you hit your finger whilst hammering, if you have to
swerve to avoid a hole in the road, or if the pen stops working, then the unconscious
use of the technology turns into a conscious interaction with the technology.
Winograd and Flores (1986) refer to this as a 'breakdown'. One aim of interactive
systems design is to avoid such breakdowns, to provide people with a way of under­
taking activities without really being aware of the technologies that enable them to
do what they are doing.

Another important aspect of usability is to try to engender an accurate mental model
of the system. A good design will have adopted a clear and well-structured conceptual
design that can be easily communicated to people. A complex design will make this pro­
cess much more difficult. Striving for a clear, sim­
ple and consistent conceptual model will increase
the usability of a system.

Challenge 4.3
The remote control for my TV is shown
in Figure 4.6. Yes, all the numbers have
got rubbed off the buttons! Write down
the processes that a user of this device
goes through if they want to enter a code
number, 357998, say.

Figure 4.6 My TV remote control
(Source: Steve Gorton and Karl Shone/
DK Images)

4.4 Acceptability


Evaluation is covered in
Chapter 10

Acceptability is about fitting technologies into people’s lives. For example, some rail­
way trains have ‘quiet’ carriages where it is unacceptable to use mobile phones, and
cinemas remind people to turn their phones off before the film starts. Apple’s iMac
computer was the first computer designed to look good in a living room. A computer
playing loud music would generally be considered to be unacceptable in an office
An essential difference between usability and acceptability is that acceptability can
only be understood in the context of use. Usability can be evaluated in a laboratory
(though such evaluations will always be limited). Acceptability cannot.

Chapter 4 • Usability

The Technology Acceptance Model
The Technology Acceptance Model (TAM) is a way of looking at technologies and whether
they will be accepted by communities. It has its origins in business studies rather than in
computing or psychology. TAM looks at technology acceptance from two perspectives:
ease of use and effectiveness. Each of these is further broken down into more specific
characteristics of the technology. There are many variants of TAM as it gets adapted to the
particular characteristics of a technology. Some of our own work involved looking at the
acceptance of biometrics. We felt that a third aspect was important to the acceptance of
biometric technology, namely trust.

The key features of acceptability are:
• Political. Is the design politically acceptable? Do people trust it? In many organiza­
tions new technologies have been introduced for simple economic reasons, irrespec­
tive of what people may feel about them and the ways that people’s jobs and lives
might change. In the broader environment human rights might be threatened by
changes in technologies.
• Convenience. Designs that are awkward or that force people to do things may prove
unacceptable. Designs should fit effortlessly into the situation. Many people send
documents electronically nowadays, but many people find reading on-screen unac­
ceptable. They print out the document because it is more convenient to carry and
• Cultural and social habits. If political acceptability is concerned with power struc­
tures and principles, cultural and social habits are concerned with the way people
like to live. It is rude to disturb other people, for example. ‘Spam’ e-mail has become
such an unacceptable aspect of life that some companies have given up on e-mail
• Usefulness. This goes beyond the notions of efficiency and effectiveness and concerns
usefulness in context. For example, many people have found the diary function
on their phone perfectly usable, but not
sufficiently useful in the context of everyday
• Economic. There are many economic issues
that render some technology acceptable or
not. Price is the obvious one and whether the
technology offers value for money. But the
economic issues go further than that as
the introduction of new technologies may
completely change the way businesses work
and how they make money. A new ‘business
model’ is often a part of economic acceptabil­ Figure 4.7 The three legs of product
ity. Don Norman characterizes the situation development
for a successful technology as a stool with (Source: after Norman, Donald A., Fig. 2.5, The
Invisible Computer: Why GoodProducts Can Fail,
three legs: user experience, marketing and ©1998 Massachusetts Institute of Technology,
by permission of The MIT Press)
technology (Figure 4.7).



Part I • Essentials of designing interactive systems

4.5 Design principles

-> M em ory and attention
are discussed in C h ap ter 21

Over the years many principles of good interactive system design have been developed.
Don Norman in his book The Design of Everyday Things (Norman, 1998) provides sev­
eral, as does Jacob Nielsen in Usability Engineering (Nielsen, 1993). However, the level
of abstraction provided by different people at different times is sometimes rather incon­
sistent and confusing. Design principles can be very broad or they can be more specific.
There are also good design principles that derive from psychology, such as ‘minimize
memory load’, i.e. do not expect people to remember too much. (We discuss many
of these principles in Chapters 12 and 13 on interface design.) Apple, Microsoft and
Google all provide user interface design guidelines for the development of products that
run on their platforms.
The application of design principles has led to established design guidelines and pat­
terns of interaction in certain circumstances such as the ‘Undo’ command in a Windows
application, the ‘Back’ button on a website or the greying-out of inappropriate options
on menus.
Design principles can guide the designer during the design process and can be
used to evaluate and critique prototype design ideas. Our list of high-level design
principles, put together from Norman, Nielsen and others, is shown below. All the
principles interact in complex ways, affecting each other, sometimes conflicting
with each other and sometimes enhancing each other. But they help to orientate
the designer to key features of good design and sensitize the designer to important
For ease of memorizing and use we have grouped them into three main categories learnability, effectiveness and accommodation - but these groupings are not rigid. Systems
should be leamable, effective and accommodating.
• Principles 1-4 are concerned with access, ease of learning and remembering
• Principles 5-7 are concerned with ease of use, and principles 8 and 9 with safety
• Principles 10-12 are concerned with accommodating differences between people
and respecting those differences (accommodation).
Designing interactive systems from a human-centred perspective is concerned with the

-> M etaphors are discussed
in Section 9.3

Helping people access, learn and remember the system
1 Visibility. Try to ensure that things are visible so that people can see what functions
are available and what the system is currently doing. This is an important part of
the psychological principle that it is easier to recognize things than to have to recall
them. If it is not possible to make it visible, make it observable. Consider making
things Visible’ through the use of sound and touch.
2 Consistency. Be consistent in the use of design features and be consistent with similar
systems and standard ways of working. Consistency can be something of a slippery
concept (see the Further thoughts box). Both conceptual and physical consistency
are important.
3 Familiarity. Use language and symbols that the intended audience will be familiar
with. Where this is not possible because the concepts are quite different from those
people know about, provide a suitable metaphor to help them transfer similar and
related knowledge from a more familiar domain.

Chapter 4


4 Affordance. Design things so it is clear what they are for; for example, make buttons
look like push buttons so people will press them. Affordance refers to the properties
that things have (or are perceived to have) and how these relate to how the things
could be used. Buttons afford pressing, chairs afford sitting on, and Post-it notes
afford writing a message on and sticking next to something else. Affordances are
culturally determined.
Giving them the seme of being in control, knowing what to do and how to do it
5 Navigation. Provide support to enable people to move around the parts of the sys­
tem: maps, directional signs and information signs.
6 Control. Make it clear who or what is in control and allow people to take control.
Control is enhanced if there is a clear, logical mapping between controls and the
effect that they have. Also make clear the relationship between what the system
does and what will happen in the world outside the system.
7 Feedback. Rapidly feed back information from the system to people so that they
know what effect their actions have had. Constant and consistent feedback will
enhance the feeling of control.
Safely and securely
8 Recovery. Enable recovery from actions, particularly mistakes and errors, quickly
and effectively.
9 Constraints. Provide constraints so that people do not try to do things that are inap­
propriate. In particular, people should be prevented from making serious errors
through properly constraining allowable actions and seeking confirmation of dan­
gerous operations.
In a way that suits them
10 Flexibility. Allow multiple ways of doing things so as to accommodate people with
different levels of experience and interest in the system. Provide people with the
opportunity to change the way things look or behave so that they can personalize
the system.
11 Style. Designs should be stylish and attractive.
12 Conviviality. Interactive systems should be polite, friendly and generally pleasant.
Nothing ruins the experience of using an interactive system more than an aggressive
message or an abrupt interruption. Design for politeness (see Box 4.4). Conviviality
also suggests joining in and using interactive technologies to connect and support

Consistency is a slippery concept because consistency is always relative. A design will be
consistent with respect to some things but may be inconsistent with respect to others.
There are also times when to be inconsistent is a good thing because it draws people's
attention to something that is important. The difference between conceptual consist­
ency and physical consistency is important. Conceptual consistency is about ensuring
the mappings are consistent, that the conceptual model remains clear. This involves
being consistent both internally to the system and externally as the system relates to
things outside it. Physical consistency is ensuring consistent behaviours and consistent
use of colours, names, layout and so on.
One famous example of the difficulty of maintaining conceptual consistency in a
design comes from the design of the Xerox Star interface (described in Smith et al., 1982).






Part I • Essentials of designing interactive systems

To print a document, the document was dragged onto a printer icon. This was consist- j
ent with the overall style. The question then arose as to what to do with it after it had
been printed. The options considered were (1) the system deletes the icon from the
desktop, or (2) the system does not delete the icon, but (a) replaces it on the desktop in
its previous location, (b) places it at an arbitrary location on the desktop, or (c) leaves it
on the printer for the user to deal with. Discuss!
Kellogg (1989) quotes the designers as saying that in this example the trade-off was
between the external consistency of not deleting the icon, as it behaved more like a
real-world object (a photocopier), against the internal consistency of behaving like
other actions in the interface, such as dragging the icon to the wastebasket or to a folder
icon. They opted for option 2a. Whether designers would do that nowadays, when
more people are much more familiar with these types of interface, is another matter.

-------------------- ---------- ---------------—---- — ------ *---------------------------------- ------ J

Polite software
Alan Cooper (1999) argues that if we want people to like our software we should design
it to behave like a likeable person. Drawing on work by Reeves and Nass (1996), who
found that people interacting with new media were treating the media like a person
('The Media Equation'), they argue that the essentials of polite behaviour are quality,
quantity, relevance and clarity. Cooper continues with his list of characteristics:
Polite software:
is interested in me
is deferential to me
is forthcoming
has common sense
anticipates my needs
is responsive
gives instant gratification

is taciturn about its personal problems
is well informed
is perceptive
is self-confident
stays focused
is fudge-able
is trustworthy

Design principles in action
In Part III of this book we look at design in a number of specific contexts including
the Web, cooperative systems, mobile computing and ubiquitous computing systems.
Specific design issues and principles for those contexts are discussed there. There are
also related issues discussed in Chapter 12 on interface design. Here we look at some
general examples of the design principles in action.
The computer ‘desktop’ is likely to remain with us for some time, with its familiar
combination of windows, icons, menus and pointer, called a WIMP interface. This form
of interaction - the graphical user interface (GUI) - is as ubiquitous as information and
communication technologies are becoming and appears on handhelds and other mobile
devices as well as on desktop computers.
Designing for GUIS, is still dominated primarily by issues of usability. In particular,
the key issue is consistency. There are clear guidelines for issues such as menu layout,
ordering, dialogue boxes and use of the other ‘widgets’ associated with graphical user
interfaces. There are standards for providing constraints such as greying out items on a
menu that are not relevant at a particular point. A toolkit, or a design environment such

Chapter 4 • Usability

as Visual Basic, will probably be used that will help to ensure that the design conforms
to an overall style.
Screen design is a key issue in such environments and attention needs to be paid to
the layout of objects on a screen. Avoiding clutter will help to ensure visibility. Attention
needs to be paid to the use of appropriate, non-clashing colours and the careful layout
of information using tables, graphs or text as appropriate. However, on mobile applica­
tions visibility is very difficult to achieve.
Often in the design of GUI applications, the designer can talk to the actual future
stakeholders of the system and find out what they want and how they refer to things.
This will help the designer to ensure that familiar language is used and that the
design follows any organizational conventions. It can be fitted in with preferred ways
of working. Participatory design techniques - involving people closely in the design
process - can be used, and stakeholders can participate in the design process through
workshops, meetings and evaluation of design ideas. Documentation and training can
be given.
A good design will ensure that there is easy error recovery by providing warning
signs for drastic actions such as ‘Are you sure you want to destroy the database?’. A good
example of designing for recovery is the Undo command.
Affordances are provided by following GUI design guidelines. People will expect to
see a menu at the top of the screen and will expect the menu items to be displayed when
the header is clicked on. Items that are not greyed out will afford selecting. The various
‘widgets’ such as check boxes, radio buttons and text entry boxes should afford selecting
because people familiar with the standards will know what to expect. However, care
needs to be taken to ensure that opportunities are easily and correctly perceived. On
mobile devices the physical buttons afford pressing, but because of the limited screen
space the same button has to do different things at different times. This leads to prob­
lems of consistency.
Menus are also the main form of navigation in GUI applications. People move
around the application by selecting items from menus and then by following dialogue
structures. Many applications make use of ‘wizards’. These provide step-by-step instruc­
tions for undertaking a sequence of operations, allowing users to go forwards and back­
wards to ensure that all steps are completed.
Control is usually left in the hands of the users. They have to initiate actions,
although some features that provide security are undertaken automatically. Many appli­
cations, for example, automatically save people’s work to help with recovery if mistakes
are made. Feedback is provided in a variety of ways. A ‘bee’ symbol or an ‘egg timer’
symbol is used to indicate that the system is busy doing something. Counters and pro­
gress bars are used to indicate how much of an operation is complete. Feedback can be
provided through sound, such as a beep when a message is received on an e-mail system
or a sound to indicate that a file has been safely saved.
Flexibility is provided with things such as shortcut keys, allowing more expert users
to use combinations of keyboard controls in place of using menus to initiate commands
and navigate through the system. Many windows applications allow the user to set their
own preferences, to configure features such as the navigation bars and menu items and
to disable features that are not often used.
In terms of style and conviviality, GUI applications are rather limited as they should
remain within the standard design guidelines (although Windows 8 is certainly more
aesthetic than previous versions). Error messages are one area where the designer can
move towards a more convivial design by thinking hard about the words used on the
messages. However, all too frequently messages appear very abruptly and interrupt
people unnecessarily.



Part I • Essentials of designing interactive systems

Challenge 4.4
Look at Figure 4.8, an example of a typical 'windows'-type application. Critique the
design from the perspective of the general design principles and from design for OS X in

Figure 4.8 'Entourage' on the Mac
(Source: Screenshot fram e reprinted by permission of Microsoft Corporation)

See Section 14.3 on
Inform ation arch itecture fo r
w ebsites

See Section 5.2 on
engagem ent

Navigation is a central issue in website design. Even if a site is well focused, it
will soon get large and so issues of how to move around a website become important.
Designers need to provide support to enable people to discover the structure and con­
tent of the site and to find their way to a particular part of the site. Information architec­
ture is an established area of study devoted to designing websites.
A key feature of consistency is the use of standard Web features such as a blue
underline for showing a link. Many sites confuse people by not making links sufficiently
visible and distinguishable from other text on the site. Flexibility of navigation can be
enabled by providing alternatives for people; different routes though the site and hav­
ing a variety of links. Having a site map will afford people getting oriented.
Issues of recovery, feedback and control figure most highly in shopping sites. There
are often long pauses when processing things such as a payment transaction. Feedback
is critical here and statements such as ‘this action may take 45 seconds to complete’ are
used to persuade people not to do anything while the transaction is processed. However,
there is no way of enforcing constraints in these circumstances.
Conviviality can be provided by allowing people to join in, to support and create
communities. Unlike standard GUI applications, websites can easily connect people
with one another. Style is also key to websites and offers the most opportunities for
designers to demonstrate their creative flair. The use of animation, video and other
design features can really develop a whole sense of engagement with the site.

Summary and key points
Good design is about usability. It is about ensuring that systems are accessible to all
and that designs are acceptable for the people and contexts in which they will be used.
Designers need to evaluate their designs with people and involve people in the design

Chapter 4 • Usability

process. Paying attention to design principles can help sensitize the designer to key
aspects of good design.
• Access to interactive systems for all people is an important right.
• Usability is concerned with balancing the PACT elements in a domain.
• Acceptability is concerned with ensuring that designs are appropriate to contexts of use.
• Twelve design principles are particularly important. They can be grouped into three
main design issues of learnability, effectiveness and accommodation.

1 Suppose that the designers of the laboratory access system described in
Chapter 2 have settled on a system that uses a swipe card and a card reader to
access laboratories. How would you set about evaluating this design? Use the
design principles to discuss the key issues.

2 Describe how design principles could be used to help in the design of the
bicycle route information system described in Chapter 2. How would this
evaluated for accessibility, usability and acceptability?

Further reading
Gould, J.D., Boies, S.J., Levy, S., Richards, J.T. and Schoonard, J. (1987) The 1984 Olympic
Message System: a test of behavioral principles of system design. Communications of the
ACM, 30(9), 758-69.
Norman, D.A. and Draper, S. (eds) (1986) User-Centred System Design: New Perspectives on
Human-Computer Interaction. Lawrence Erlbaum Associates, Mahwah, NJ.
Stephanidis, C. (ed.) (2001) User Interfaces for All: Concepts, Methods and Tools. Lawrence
Erlbaum Associates, Mahwah, NJ. A good collection of papers on accessibility.

Getting ahead
Kellogg, W. (1989) The dimensions of consistency. In Nielsen, J. (ed.), Coordinating User
Interfaces for Consistency. Academic Press, San Diego, CA.
Smith, D.C., Irby, C., Kimball, R., Verplank, B. and Harslem, E. (1982) Designing the Star
user interface. BYTE, 7(4), 242-82.

Web links
The W3C's Web accessibility project is at
The accompanying website has links to relevant websites. Go to



Essentials of designing interactive systems

Comments on challenges
Challenge 4.1
This, of course, is a real problem not just for the UK government but for authorities worldwide
as they seek to save costs by making use of electronic methods of delivery. The potential barri­
ers include fear of computers amongst some people (often the most vulnerable and in need of
support). If this can be overcome then physical access to a computer is necessary, or via other
technologies such as interactive TV. However, the interface to interactive TV is still quite poor and
the functionality is also limited. Access can be provided in public buildings such as libraries and at
social security offices where staff could be on hand to help people enter their details. There are also
factors such as privacy where people may not want to provide the sort of detail that is required,
or they may distrust the gathering of this information and may need clear reassurance on how any
personal data would be used.

Challenge 4.2
The postcard needs a pen to write it - a felt-tipped pen would be too big. But I like writing with felttipped pens when I am playing around with some ideas in a notebook - sitting on a train, perhaps.
A laptop computer is quite good and saves the trouble of having to transfer things from a book to
the computer, but you cannot use a laptop when taking off or landing in a plane whereas you can
still write in your book. I have tried the palmtops and handwriting, but have not found it a very sat­
isfying way of working. Perhaps it is better for people who have to write short amounts of material.
Challenge 4.3
There is a lot of bridging of gulfs! Since the display is on the TV, feedback is very poor. In my case
I need to take my glasses off to see the remote and put them on again to see the TV. There is a lot
of taking my glasses on and off! With no numbers on the remote, the feedback that would usually
come from this source is no longer there.
Challenge 4.4
Aesthetically the display is quite pleasant. There is not much clutter, which ensures that most things
are visible. Parts of the display can be made larger and smaller, allowing the sort of flexibility that is
needed for different people doing different things. Of course, the design is wholly consistent with
the Macintosh guidelines. One interesting problem with Entourage is that it does not let people
recover easily from inadvertently moving e-mails. For some reason 'Undo' does not relate to trans­
ferring e-mails into folders. The use of different font styles for read and unread messages affords
focusing on the unread ones, and constraints on allowable actions are enforced - e.g. if you try to
move an e-mail message to an inappropriate place it springs back.
Overall this system demonstrates the implementation of many of the design principles recom­
mended in Section 4.5.

4 h


Chapter 5

f *

Experience design

4 *





Designers of interactive systems are increasingly finding themselves
going beyond the design of usable systems and are instead expected
to design systems that provide people with great experiences. Of

Introduction 94

5.2 Engagement 95
5.3 Designing for pleasure 99
5.4 Aesthetics 102
5.5 Service design 104
Sum m ary and key points 107
Exercises 107
Further reading 107
Web links 108
Com m ents on challenges 108

course games designers have been doing exactly this for years, but
more recent platforms such as the iPhone and Wii are blurring the
distinction between games and regular applications. A shopping list
application on the iPhone, for example, needs to be much more than
functional; it needs to be fun to use, engaging and enjoyable. Websites
have to attract and keep customers if they are to be profitable and,
once they provide appropriate functionality and content, they will
do that only if people enjoy using them. Ubiquitous computing
environments need to be responsive to people's needs, but also need
to provide engaging and aesthetic experiences.
In this chapter we explore the factors that contribute to creating highquality experiences for people using interactive systems. This area of
HCI and interaction design is often called user experience (UX), though
terms such as customer experience (CX) are also used and help us
move away from the term 'user'.
After studying this chapter you should be able to;
• Discuss ideas of experience and the different traditions from which
concepts come
• Understand Nathan Shredroff's model of experience
• Understand 'designing for pleasure'
• Understand the importance of aesthetics
• Understand service design.


Part I • Essentials of designing interactive systems



Contributions to an understanding of experience design come from many different areas.
Nathan Shedroff (2001) published a very engaging book on the subject and McCarthy
and Wright explore the wider issues of experiences through their book Technology as
Experience (2004), drawing on the philosophy of John Dewey, an American Philosopher
and psychologist writing in the mid twentieth century. Patrick Jordan and Don Norman
have both published books on the importance of designing for pleasure and others talk
about ‘ludic’ design, ‘hedonomics’ and ‘funology’. Work on aesthetics has a long history
and has recently been applied to interactive systems design.

Homo Ludens
Homo Ludens was the title of a book by Johan Huizinga written in 1938 concerning the
importance of play in culture. In it he explores the concept of play in different cultures.
Play is about freedom, it is extraordinary. It has been popularized in interaction design
through Bill Caver's work on what he calls 'ludic' design. In an online interview, Gaver
1 don't mean joining in a set of arbitrary rules to see who can win some situation. On
the contrary, I mean by 'play' something more fluid and self-motivated. So examples
of play are anything from fooling around with friends and taking on imaginary roles
when you are having a chat, to stacking up things to see how many you can balance on
one another before they all tumble down, or taking a new walk on the way home from
work just to see where you get. But also I tend to allow the category to extend beyond
the obviously playful to take in things like enjoyment of the scenery, or staring out the
window and wondering about how the wind is moving around the leaves and trees and
so forth.
Gaver has expressed these ideas through a number of playful household objects, includ­
ing the drift table and history tablecloth (Figure 5.1). The drift table was a coffee table that
tilted and showed maps of the UK. The history tablecloth displayed imprints of the objects
that had been recently placed on it.

Figure 5.1 (a) Drift table and (b) History tablecloth
(Source: Copyright the Interaction Research Studio, Goldsmiths)

Chapter 5

Experience design is about recognizing that interactive products and services do not
just exist in the world, they affect who we are. They influence our culture and identity.
As Dewey says, ‘experience is the irreducible totality of people acting, sensing, think­
ing, feeling and meaning-making including their perception and sensation of the arti­
fact in context’ (quoted in McCarthy and Wright, 2004). For Jodi Forlizzi experience
is ‘the constant stream of self-talk that happens while we are conscious’. In addition to
experience, Forlizzi stresses the importance of the social side of things in co-experience
(Forlizzi and Batterbee, 2004).
Experience is concerned with all the qualities of an activity that really pull people
in - whether this is a sense of immersion that one feels when reading a good book, or a
challenge one feels when playing a good game, or the fascinating unfolding of a drama.
It is concerned with all the qualities of the interactive experience that make it memora­
ble, satisfying, enjoyable and rewarding. Emotion is a very important part of experience
as experience is about feeling.
In their treatment of technology and experience, McCarthy and Wright highlight the
need to take a holistic approach to experience. Their approach is holistic, constructionist
and pragmatic. The argument is that experiences have to be understood as a whole and
cannot be broken down into their constituent parts, because experience lies in the rela­
tions between the parts. Interactivity, as we have seen, involves the combination of people,
technologies, activities and the contexts in which the interaction happens. This context
includes the wider social and cultural context as well as the immediate context of use.
McCarthy and Wright take a stance that emphasizes the rights of people to have the
experiences they need and desire rather than having experiences thrust upon them by
poor designs. Through experiences we live our lives and this is how we develop our val­
ues and sense of self-worth. Experiences are about how we bring artefacts and services
into our lives and accept them. Ross et al. (2008) develop similar ideas through their
notion of enchantment.
Experiences, therefore, cannot really be designed. Designers can design for experi­
ence, but it is individuals and groups who have the experience.



Engagement is about ensuring that the interaction flows. If usability is concerned with
optimizing or balancing the PACT elements in some domain, engagement is when the
PACT elements are truly harmonized.
There is, of course, much debate as to what the key features of engagement are and,
arguably, this is really the domain of artistic creation. However, Nathan Shedroff in his
book Experience Design (Shedroff, 2001) presents a ‘manifesto’ for what he sees as a new
discipline. From his work we identify as the key elements:
• Identity. A sense of authenticity is needed for identity and expression of the self. The
sense of authenticity is often only noticed when it breaks down. If you are engaged
in some experience and something happens that suddenly reminds you that it is not
real, then the authenticity of the experience can be lost. Shedroff is also getting at the
idea of identifying with something as a key element of engagement. Are you a Mac or
a Windows person or don’t you care?
• Adaptivity is to do with change and personalization, with changing levels of diffi­
culty, pace and movement. Musical instruments are often cited as examples of great
interaction design. Engagement is not about making things easy; it is about making
things that can be experienced at many levels of skill and enjoyment.

Experience design



Part I • Essentials of designing interactive systems

• Narrative is to do with telling a good story, with convincing characters, plot and sus­
pense. Narrative is not just about fiction, however. Good narrative is just as important
for a company’s promotional video, a lecture on interaction design, a menu structure
on a mobile phone or any other design problem.
• Immersion is the feeling of being wholly involved within something, with being taken
over and transported somewhere else. You can get immersed in all manner of things
(such as reading a book) so immersion is not about the medium; it is a quality of the
• Flow is the sense of smooth movement, the gradual change from one state to
another. Flow is an important concept introduced by the design philosopher Mihaly
Csikszentmihalyi (1990) (see the Further thoughts box on this).
A medium is engaging if it draws the person in, if it seems to surround the activity,
if it stimulates the imagination. Malcolm McCullough in his book Abstracting Craft
(McCullough, 2002a) argues that an engaging medium allows for continuity and vari­
ety, for ‘flow’ and movement between many subtle differentiations of conditions. The
medium can take many slightly different positions along a spectrum that are just dis­
cernible by a person. Think of the way the lights go down in a cinema just before the
movie starts. The sense of anticipation, satisfaction and being drawn in is created by
the just discernible change in lighting. Interactive technologies are the medium that the
interactive system designer shapes.

Challenge 5.1
Think about your favourite activity. It may be talking to a friend on your mobile phone,
driving your car, riding your bike, playing a computer game, going to the cinema,
shopping or attending a lecture. Using Shedroff's five features above, analyse what it is
about the activity that makes it engaging. Could it be more engaging if the design were

.................................................. J


Digital ground: fixity, flow and engagement with context
'Flow needs contexts. A river, for example, needs riverbanks otherwise it spreads out in
every direction until it becomes a brackish swamp. Similarly, cars need highways, capital
needs markets and life's energy needs bodies through which to course.
Flows influence one another. For example, we know that telecommunication gen­
erates transportation at least as often as it substitutes for it, starting with Alexander
Graham Bell whose first words on his new telephone were 'Watson, please come here'.
Similarly, when you order a book from Amazon, the flow of data on the web has an
effect outside the web, namely it causes a package to be put on an airplane. This in turn
has geographic consequences: the warehouse where your order is filled is probably
located near an airport.
Where regular crossovers between flows occur, places emerge.
Here we arrive at Mihaly Csikszentmihalyi's often-cited expression: Flow is the sense
of engagement that emerges, between boredom and anxiety, when practiced abilities
are applied to challenges that are just about manageable. This notion of engaged tacit
knowledge grounds much interaction design. We tend to be familiar with psychological
notions of "activity theory", "situated actions" and "persistent structures". We know how
.......-..................................................-.................... - ..........- - ---- --------- ------ - - ..................... J

Chapter 5 • Experience design

possibilities for action are perceived especially amid engaged activity (and we over­
use the word "affordance" to describe this). Increasingly, we understand how that per­
ception depends on persistent structures, both mental and physical, that surround and
give meaning to those activities. We recognize how such response to context is not
necessarily deliberative. We find the phenomenology of engagement at the roots of
So this is the heart of the matter: Flow needs fixity. Persistently embodied intentional
settings, also known as architecture, provide a necessary context for Flow.'
Source: McCullough (2002b)

Computer games have to be designed to be engaging and many of the principles of
engagement can be seen in the design of games. Increasingly these principles are being
applied to various interactive systems. Websites need to hold people’s attention and
principles of games (‘gamification’) can be used to interest and motivate people.
An engaging animated computer game will allow for subtle differentiations of con­
ditions. An important feature here is also the integration of media. A boring computer
game relies on too little change and flow and too little depth in the media components.
Computer games illustrate all the other features of engagement above - a feeling of
immersion, the need for a good story line, the authenticity of the game play and identi­
fication with characters, the different levels accommodating different abilities and the
gradual smooth change of scenes: the flow. One of the most engaging games was Myst
which appeared on the Macintosh in the early 1990s and remains a bestseller today with
versions on the iPhone and Nintendo DS. Figure 5.2 shows some of the images from the
game, but the atmosphere was considerably enhanced by excellent use of sound and by
character and the slow pace of the movement.

Figure 5.2 Pictures for the game Myst
(Source: © Cyan Worlds, Inc. Used by permission)



Part I • Essentials of designing interactive systems

Nicole Lazzaro (Lazzaro, 2012) draws the link between fun and emotion in her con­
tribution to understanding what makes interactive activities engaging. She identifies
five ways that emotions impact the gaming experience:
-> Chapter 22 covers
emotion, or 'affect as it is also


Enjoy. Emotions create strong shifts in internal sensations.
Focus. Emotions help gamers to focus effort and attention.
Decide. Emotions are central to decision making in games.
Perform. Emotions increase appeal to enhance performance.
Learn. Emotions are important for motivation and attention.

Lazzaro presents the Four Fun Key model in which she distinguishes four different
types of fun — hard fun, easy fun, serious fun and people fun — each of which goes on
to unlock emotions such as curiosity, relaxation, excitement and amusement, that con­
tribute to a good player experience. More generally we can see these as key emotions in
contributing to a high-quality user experience.
(a) Hard fun is concerned with overcoming adversity, the emotion that Lazzaro calls Fiero.
It relates to the gamification effects of mastery, challenge and strategy. For example, in
a car racing game it is no fun if it is hard to start the car and start the race. However, it
is fun if it is hard to avoid the obstacles or keep the car on track whilst driving fast. The
hard fun comes from mastering the driving.
(b) Easy fun evokes the key emotion of curiosity. Gamification mechanics such as nov­
elty, ambiguity, fantasy and role play make people curious to explore the interac­
tion. It is more open-ended interaction than the focused, goal-centred interaction of
hard fun.
(c) Serious fun is about relaxation. It arises when an interactive experience provides
rewards that increase people’s self-worth and allow them to focus on activities.
Serious fun is about doing work!
(d) People fun concerns the emotion of amusement. It arises when people are con­
nected to one another in cooperative or competitive activities. It is the social side of
gamification, connecting into people’s social networks and desire to share.
Using these four fun keys helps the interaction designer to produce a UX that moves
the user through different emotions, helping to create engaging experiences. In
terms of the design process, interaction designers need to consider what type(s)
of experience(s) they are trying to create for users of their systems. The four fun
keys provide a good way into thinking about this. Subsequently designers can con­
sider the mechanisms that they are going to use to try to evoke those experiences.
These include:
• Deciding what challenges to include in the product and whether these are short-term
challenges or longer-term ‘quests’
• Deciding how to deal with the different skill levels of different users and how to
accommodate changing skill levels
• Deciding what rewards to provide people with and how rewards relate to challenges
and skill levels
• Deciding if people can collect things, or complete things like puzzles, and if they do
collect things how they relate to rewards, abilities and skills
• Deciding how people will relate to other people through competition such as league
tables and posting achievements or through cooperation and working with others to
achieve a common goal.

Chapter 5






Experience design


Designing for pleasure

Product designers have long been concerned with building in pleasure as a key mar­
keting point. Pleasure is a focus for many design situations that were once much more
dominated by the more functional aspects of
usability. The Apple MacBook Air is advertised
as being lightweight and elegant (it is only 3 cm
thick), with a distinctive and attractive titanium
shell (Figure 5.3). While all of these features
contribute to the laptop’s usability, they also
contribute to the pleasure of owning, using and
(perhaps) being seen with it.
Patrick Jordan’s book Designing Pleasurable
Products (2000) argues effectively that design­
ing for pleasure can be as important as ensur­
Figure 5.3 Apple MacBook Air
ing that an interactive device is usable. Jordan
(Source: Hugh Threlfall/Alamy Images)
describes pleasure as being ‘the condition of
consciousness or sensation induced by the enjoyment or anticipation of what is felt or
viewed as good or desirable: enjoyment, delight, gratification’. In the context of interac­
tive devices or products, designing for pleasure contributes to ‘emotional, hedonistic
and practical benefits’ (Jordan, 2000, p. 12).
Jordan’s approach draws heavily on the work of Lionel Tiger, who is an anthropolo­
gist and has developed a framework for understanding and organizing thinking about
pleasure. This framework is discussed at length in Tiger’s book The Pursuit of Pleasure
(Tiger, 1992). Tiger has argued that there are four dimensions or aspects of pleasure.
These are physio-pleasure, socio-pleasure, psycho-pleasure and ideo-pleasure.

This is concerned with the body and the senses. Physio-pleasure arises from touching or
handling devices or from their smell - think about the smell of a new car, or the pleas­
ingly solid but responsive feel of a well-designed keyboard. This sort of pleasure is also
derived from using devices which fit seamlessly with the human body - although this
is more usually noticed when the fit is less than ideal. The physical fit of technology to
people has long been a central concern for ergonomists working on the design of new

Socio-pleasure arises from relationships with others. Products and devices which have
a socio-pleasurable aspect either facilitate social activity or improve relationships
with others. A very obvious example is the key role which text messaging has rap­
idly acquired in enhancing social communication for many people, the use of Twitter
to keep in touch, or the popularity of social networking websites such as Facebook.
Pleasure derived from enhanced status or image is also considered a socio-pleasure,
and of course is much exploited by the vendors of successive generations of small per­
sonal technologies.

There is more about
ergonomics in Chapter 2



Part I • Essentials of designing interactive systems

Psycho-pleasure (short for psychological pleasure) refers to cognitive or emotional
pleasure in Tiger’s framework. This dimension of pleasure is useful for pulling together
sources of pleasure such as the perceived ease of use and effectiveness of a device and
the satisfaction of acquiring new skills. For some people, learning a complex program­
ming language generates a degree of satisfaction which would never be obtained from
moving icons around the screen in a GUI.

Ideo-pleasure (ideological pleasure) concerns people’s values - things one holds dear or
meaningful - and aspirations. We are more likely to enjoy using items that fit our value
system. Aspects which come readily to mind here might include a respect for careful
craftsmanship and design, the desirability or otherwise of having an obviously expen­
sive device, and our perceptions of the trading ethics of the supplier (for example, com­
mercial software as against free shareware).

The four dimensions in practice
It should be remembered that these four dimensions are simply a method of structuring
design thought rather than a description of the nature of pleasure itself.
Let’s see how they work by returning to the example of the MacBook Air laptop and
analysing it against Tiger’s four pleasures.

Culture and identity are
discussed in Chapter 24

1 Physio-pleasure. The machine is light, the texture of the titanium shell is pleasing and
the keyboard is responsive.
2 Socio-pleasure. Certainly when first released, owning a MacBook Air might be thought
to enhance image as it distinguishes the owner as someone with the discernment to
adopt a stylish remodelling of the laptop. There is also a certain socio-pleasure in
being part of a small group of Apple devotees among a much larger community of PC
users in our particular workplace.
3 Psycho-pleasure. The MacBook Air provides relatively seamless integration between
different media and so generates satisfaction from streamlining many work tasks.
4 Ideo-pleasure. For some consumers, Apple products remain an embodiment of inde­
pendence, creativity and free-thinking - attributes inherited from the early image
of the corporation. Whether this is still an accurate perception is not the point: it is
enough that people feel that it is so.

Challenge 5.2
Using Tiger's classification, what do you consider is the main pleasure evoked by the
design of one of the interactive devices/systems you enjoy owning or using? If possible,
compare your response to those of one or more colleagues for a similar device.
M M M M M M M M H M M H M M H M M IIM M M M M M IM M M M n M ia M M flM W M W IN M B iM M H M lM F

Product attachment theory
Zimmerman (2009) discusses how to bring product attachment theory into interaction
design. Product attachment concerns the feelings that people have for products and the
ways in which the products take on meanings for them. He reflects on a number of prod­
ucts from the perspective of ‘designing for the self, by which he means designing for

Chapter 5 • Experience design

other people to realize themselves through interacting with the product. He looked spe­
cifically at six products (Figure 5.4) and at the characteristics they possessed in terms of
design patterns. Design patterns are regularities in designs that capture some aspects of
successful design. Design patterns are an important part of interactive systems design
and are discussed in Chapter 9 as part of our design approach.
The products examined by Zimmerman included Cherish, a smart photoframe (top left
in Figure 5.4), a smart bag for organizing and carrying athletic kit that is connected to the
family’s calendar (top middle, Figure 5.4) and the reserve alarm clock (bottom middle in
Figure 5.4) that aimed to stop children waking their parents at night. From his analysis he
arrived at six ‘framing constructs’that captured important elements of product attachment:
1 Role engagement concerned support for the different roles that people play in their
lives. It arises from the observation that people have to switch roles depending on the
context, such as the time of day, or relationship required for a particular activity.
2 Control concerned empowering people, giving them control over the product. This
could be control over the ‘look and feel’ of the product, personalizing it to their tastes,
or it could be control over the functionality of the product.
3 Affiliation concerns how people develop feelings for a product by ensuring that the
product meets a real need for them.
4 Ability and bad habit is a construct concerned with enhancing people’s abilities and
preventing them making mistakes or engaging in their bad habit. The smart bag, for
example, stopped people forgetting things.
5 Long-term goals need supporting as well as short-term functions. People build their
attachment by recognizing that the product supports their long-term goals.
6 Ritual concerns how the product fits in with important ritual aspects of the person’s life.
Zimmerman encourages designers to keep these framing constructs in mind during the
understanding, envisioning, designing and evaluation processes of the whole design
process. In doing so they will focus more on designing for the self, and on developing
products that people will form an attachment to.

Figure 5.4 Products examined by Zimmerman - Ensure, designed by Hee Young Jeong and Sun Young Park;
Smart Bag, designed by Min-Kyung Lee; Cherish, designed by Jeong Kim; Share Moments, designed by Rhiannon
Sterling Zivin; Magonote, designed by Mathew Forrest; Reverse Alarm Clock, designed by Kursat Ozenc
(Source: Zimmerman, J. (2009) Designing for the self: making products that help people become the person they desire to be, CHI '09: Proceedings
of theSIGCHI Conference on Human Factors inComputingSystems, pp. 395-404. © 2009 ACM, Inc. Reprinted by permission,



Part I • Essentials of designing interactive systems


Kansei engineering is concerned with bringing an emotional and aesthetic element to
engineering. It is used across all manner of engineering design practices in order to try
to understand and embody what it is that will get people really involved in a design. To
date it has been applied very little in interaction design.
Kansei sits alongside Chinsei as one of two threads of the design and engineering
process, Kansei dealing with the emotional and Chinsei with the functional.
Schutte, S. (2005). Engineering Emotional Values in Product Design - Kansei Engineering in Development.
Doctorate Thesis, Institute of Technology, Linkoping University.
..................................................................................................................................................................................................... - ...................................... ............................... —




5.4 Aesthetics
Aesthetics is a large area of study concerned with human appreciation of beauty and
how things are sensed, felt and judged. Aesthetics takes us into the world of artistic
criticism and the philosophy of art itself. The perennial debate here is whether aesthet­
ics can ever be inherent in something, or whether ‘beauty is in the eye of the beholder’.
In terms of the design of interactive systems, aesthetics has become increasingly
important over the past few years from a number of different directions. From the
perspective of work on emotion, both Don Norman and Pieter Desmet emphasize the
importance of taking emotions into consideration in design. Norman’s book Emotional
Design (2004) discusses people’s experiences in terms of visceral, behavioural and
reflective elements. At the visceral level lies the perceptual aesthetics of an experi­
ence. At the behavioural level a positive emotional response will come from feeling
in control and from the understanding that comes through use. At the reflective level
are issues of personal values and self-worth. Pieter Desmet identifies a number of
product emotions in his book Designing Emotions (2002). He sees these as a manage­
able set of emotions, such as boredom, inspiration, amusement and so on that are
particularly relevant for product designers. This work has resulted in a database of
anecdotal evidence about products and emotions, the product and emotion navigator
and a non-verbal method for measuring people’s response to product features, called
PrEmo. PrEmo consists of fourteen animations of a cartoon character, each expressing
an emotion. There are seven positive emotions, i.e. inspiration, desire, satisfaction,
pleasant surprise, fascination, amusement, admiration, and seven negative emotions,
i.e. disgust, indignation, contempt, disappointment, dissatisfaction, boredom and
unpleasant surprise (Figure 5.5).
Hassenzahl (2007) discusses aesthetics in terms of pragmatic attributes and hedonic
attributes. Lavie and Tractinsky (2004) see the aesthetics of interactive systems in terms
of classical aesthetics (clean, clear, pleasant, aesthetic, symmetrical) and expressive aes­
thetics (original, sophisticated, fascinating, special effects, creative). They assert that
“what is beautiful is useable’. However, Hartman et al. (2008) see it as more complex
than this. Certainly, there is more than traditional usability at work in people’s judge­
ments of quality of interactive systems, but at times people will rate usability as most
important. Content, services and brand are also factors to be taken into consideration.
For Boehner etal. (2008) the issue is to make products not just right, but meaningful.
They seek to intimately couple the codification necessary in design with the ineffable
nature of human experience.

Chapter 5

Challenge 5.3
Go to a website you particularly like and critique the aesthetics of it. Could they be

..... —


rf _

..^ .- ------ .......... .......^

. .






Use the scales to report if the feelings expressed by the characters
match your own feelings towards the product in the picture.
I feel this strongly
I feel this somewhat
I do not feel this

Figure 5.5 PrEmo
(Source: Desmet, P.M.A. (2003), pp. 111-23)

The development of a brand identity is an important part of people liking and enjoy­
ing a system. Some people are 'Nokia' people, others are 'Apple' people. Some people
love Nike and others Reebok. These companies spend a great deal of effort and money
developing, refining and promoting their brand. They like to be associated with certain
events, or to sponsor certain football or baseball teams, as these associations help to
develop the brand. A brand will often deliver consistent guidelines for designers, such
as colours, use of particular fonts and so on. Brand immediately leads to a sense of
identity, one of the key aspects of experience. And conversely, experience will affect the
brand. People's experiences in interacting with branded products and services create
the feelings and values they have for the brand.

Experience design



Part I • Essentials of designing interactive systems


Social m edia are
discussed in C h ap ter 15

Service design

Gillian Crampton-Smith (2004) has argued that ‘The job of the designer is now not just
to design the device, the software, and the way you interact with it, but to design the
whole experience of the service so it is coherent and satisfying’ (p. 3). Dan Saffer (2008)
defines a service as ‘a chain of activities that form a process and have value’ (p. 175).
The key thing about service design is that there are multiple ‘touch points’ where peo­
ple encounter a service and the interactions with services happen over time. To be well
designed these touch points need to demonstrate a consistent look and feel, and present
consistent values (e.g. Live | Work in Moggridge, 2007, pp. 412-29). A great example
of service design in the early 2000s was Orange, with a consistent approach to bills,
adverts, shops, the online presence and the mobile presence. Interactions with services
typically happen intermittently and take place from different locations and devices. The
PACT elements describe services just as well as any other interaction, but the focus of the
activities needs to accommodate how the service is created, structured and delivered.
Brand is typically an important aspect of service design (see Further thoughts box).
People need to recognize that they are interacting with the same entity (the service
provider) even though they are using different technologies and different environ­
ments to do so. In service design, designers are concerned with providing resources
to enable people-to-provider interactions. Services are more intangible and flexible
than products. People do not walk away carrying a service, they take away the results
of a service. Services are co-created to a large extent, negotiated between consumer
and provider. Figure 5.6 illustrates the concept of a customer journey through the vari­
ous touch points of a service and how these relate to different aspects of social media.
These customer journey maps help the designer view the whole service from the user’s

The end of the seven-layer model

for software engineering and interaction design. Firstly, the application no longer gov­
erns and the seven-layer Open Systems Interconnection (OSI) model that has d o m i­
nated software since its inception becom es inadequate. Data and interaction history
now have to be shared across applications. In the past the application as the top layer
o f the OSI model controlled interaction, the context o f functions and the overall qual­
ity o f service. In the next generation of software such details w ill need to be shared by
applications and there is no standard protocol fo r doing this.

A consistent and engaging service must fit in with people’s lifestyles. Interactivity in the
next generation is distributed in time and place, the touch points. Saffer highlights the
importance of service moments that these touch points provide and the need to design
for these moments. Moments come together as service strings, as short paths of an over­
all process description. To2 achieve this the interface and the history of interactions
have to be transmitted between touch points, carried by the individual so that quality of
service, security, privacy and quality of interactive experience are all maintained across
places and across time. There are both short-term and long-term interactions and the
service needs to know what is mine, what I am interested in and who I am willing to
share what with; and how this changes depending on how I am feeling. In short, the
service needs to know about my lifestyle.

T h e C u s to m e r Jo u rn e y C a n v a s

Service Provider







How is the service proposition communicated
by the service provider?

Which touchpoints do customers experience during the service journey?
Are there any critical incidents, i.e. touchpoints customers experience as especially good or bad?

How does the service provider follow-up with customers?

Which pre-service information can people access
through social media?
What do customers communicate about the service and/or
service provider through social media?

What do friends, colleagues and family actually
communicate about the service and/or service provider?

What do customers tell their friends, colleagues and family
about the service and/or service provider?
Which experiences do people have with (similar)
services and/or service providers?



What are the individual experiences customers have with the service and/or service provider during the service period?

Customers individually assess the service bycomparing service
expectations with their personal service experiences.


Figu re 5 .6 The custom er journey canvas



C h ap te r 5 • Experien ce design

What are (potential) expectations towards the
service and/or service provider?




Part I • Essentials of designing interactive systems

Challenge 5.4

Think about the changing nature of the telephone service - from the days when
everything went through an operator to the combination of texts, calls and Web access
you get nowadays. How do you rate the service you get?

Section 24.4 covers


------ ------



---------------------- ----------------------------


- - -...................................................-......................................-

......... ...........................................

The developing importance of lifestyles, and the changing nature of interactions in the
twenty-first century, have led us to explore an approach to design that we call Designing
by Lifestyles (DbL). DbL is an approach to design that aims to deal with service HCI in the
2010s. A key feature of designing for the new environments is that designers cannot ‘gather’
requirements from observing people or interviewing people using existing systems. There
are no existing systems and, moreover, there are no requirements in the sense that the sys­
tems are aiming to meet a particular need. Designers are required to create experiences and
new services. However, as we know, designers also need to understand the characteristics
of the people who will use their new services and engage with the new experiences.
The notion of a ‘lifestyle’ is deliberately constructed to be more abstract than per­
sonas and scenarios. Lifestyle focuses on the ways in which people lead their lives, on
their aspirations rather than their intentions, on their values and on their search for
identity. There are details of lifestyles and activities associated with lifestyles, but these
vary across different domains and environments. There is a presence of services (touch
points) and the presence of others (both real and virtual) and interactions appropriate
to time, place and circumstance. We characterize this as shown in Figure 5.7 where the
keystones of presence, interaction, domain and environment come together to define a
lifestyle at the levels of characteristics, activities and aspirations.
Besides these different concepts, DbL makes use of four enabling envisionment tech­
niques that allow for rapid prototyping of ideas and engagement of people with evolving
designs: video scenarios, style sketches, software demos and Wizard of Oz. Video scenar­
ios allow designers to envision future interactions in video, style sketches are similar to
mood boards and Wizard of Oz systems replace not yet available technology by a human
(discussed further in Chapter 8). These four forms of representation provide the overall
framework for the DbL approach, moving from the conceptual to the concrete much as in
a scenario-based design approach, where we move from stories to conceptual scenarios
to concrete scenario and use cases. The constructs used in DbL are pitched at a more

Figure 5.7 Key constructs of Designing by Lifestyles

Chapter 5 • Experience design

abstract level to help designers think in the wider context of the heterogeneous, distrib­
uted interactions that characterize lifestyles and the services they require.
One key design ambition of service design is to achieve a recognizable consistency
and branding across experiences. Interactions must be transferable across applications.
There is also a need for aesthetic and emotional interaction. Lifestyles are concerned
with how people feel about things, with values and with changes in feelings over time
as a result of interactions. Experiences between people and technology need to develop
over time, and move from interactions to relationships.

Summary and key points
Experience design is concerned with all the issues that go into providing an engaging
and enjoyable experience for people in both the short and longer term. This includes
aesthetics, pleasure and emotional engagement in terms of both the product and the
service provided. In particular, it is important to consider experiences at a physical,
behavioural and social level and in terms of the meanings people derive from their expe­
riences. Experience design draws on:
• Theories of experience
• Theories of emotion
• Theories of aesthetics
• Theories of games.



How far is it necessary to understand the theory of human emotions in order
to design affective technologies? Illustrate your answer with examples.
Develop a storyboard showing the proposed use of an affective operating
system designed to respond when it detects frustration and tiredness in its user.
Consider a standard desktop PC and a small interactive device such as a
palmtop, mobile phone or digital camera. Choose recent examples.

(a) Analyse each device against Tiger's four principles, attempting to
determine which (if any) the designers were intending to evoke, and note
the results of your analysis.



Conduct a PACT analysis for each of the two products you have chosen.
(PACT - people, activities, contexts and technologies - was introduced in
Chapter 2.) Taking account of the results of this, discuss whether pleasure
should be an important design feature for the technologies in question.
Explain your reasons.

Further reading

McCarthy, J. and Wright, P. (2004) Technology as Experience, MIT Press, Cambridge, MA.
Norman, D. (2004) Emotional Design: Why We Love (or Hate) Everyday Things. Basic Books,
New York.



Part I • Essentials of designing interactive systems

Getting ahead
McCullough, G. (2002) Abstracting Craft: The Practiced Digital Hand. MIT Press, Cambridge, MA.
Shedroff, N. (2001) Experience Design. New Riders, Indianapolis, IN.

(||j|) Web links
AIGA, the professional association for design is at
The accompanying website has links to relevant websites. Go to


Comments on challenges
Challenge 5.1
The computer game Myst was a huge success when it first appeared in the mid-1990s. I spent sev­
eral years playing it off and on with my son until we had finally solved all the puzzles and travelled
to all the different worlds.
• Identity - the game soon developed a dedicated following of people who identified with the
mysterious worlds in which the game took place.
• Adaptivity was key to the success of the game. Like many games, there were levels that became
harder and harder. Once the challenges of one level had been completed, the players were
ready for the next. But also like many games, without the 'cheats' many players would not pro­
gress past level 1!
• Narrative was also keenly observed in Myst. All the game's players knew was that something
terrible had happened to two brothers. The purpose of the game was to discover what had hap­
pened. Snippets of information were carefully revealed as the players progressed through the
game to maintain the momentum of the narrative.
• Immersion was remarkable given the tiny screen of the early Mac computers. However, the
speakers on our machine were good and the sound in Myst excellent and very evocative, with
chilling winds blowing and the sounds of water trickling in the distance. Turn off the light on a
dark winter's afternoon and you were transported into the Myst worlds.
• Flow was present, as the scenes shifted gently from one to another and as vistas one saw from a
distance gradually came into view. It is much better in later, animated versions of the game.

Challenge 5.2
As you will probably find, in our context, Tiger's classification is a useful guide to thinking about
pleasure rather than a hard-and-fast set of categories. You are likely to find that people's responses
vary - even for an identical product - so think about how such information could be used to guide
design choices.

Challenge 5.3
You will need to debate the issues of whether beauty is in the eye of the beholder, or whether there
are good general rules. Discuss the site in terms of classical aesthetics (clean, clear, pleasant, aesthetic,
symmetrical) and expressive aesthetics (original, sophisticated, fascinating, special effects, creative).

Challenge 5.4
There are many general issues to think about as services change from being provided by people
to being provided automatically - and hence losing the 'personal touch'. Services on phones now
cover a lot more than just making calls, of course. And the type of service and the brand identity are
key aspects of deciding which provider to use.

Chapter 6
The H om e Inform ation
Centre (HIC): a ca se study in
designing interactive system s




In this chapter we will use a case study to illustrate many of the
features of the design and evaluation of interactive systems that you
have encountered. The case concerns the development of a new
concept for a device known as the Home Information Centre (HIC).
It was a real project in which our research centre was leading the
interaction design component. We were a design team of a full-time
designer and two full-time PhD students, and several students who
worked on specific aspects of the design. Elsewhere in this book we
have included examples that arose from the project. We used the
scenario-based design method discussed in Chapter 3 and many of the
specific techniques described in Chapters 7-13. The aim of the chapter
is to illustrate the process we went through and to highlight the types
of decisions and issues that arise during an interaction design project.

Introduction 110

6.2 Scenarios for the HIC 111

Evaluating early interface
prototypes 119

6.4 A first design 122
6.5 The second interface
design 126
Sum m ary and key points 131
Exercises 131
Further reading 132
Web links 132
Com m ents on challenges 132

After studying this chapter you should be able to:
• Understand how to undertake an interaction design project
• Discuss how design decisions are made in an interaction design
• Understand the trade-offs that are inherent in such a project
• Appreciate the central role of evaluation in design.


Part I • Essentials of designing interactive systems



The concept for the HIC came from the observation that there are two typical situations
in the home. The TV, video, DVD and music centre are in the living room. It is a ‘leanback’ situation, where people are being entertained and where they relax. In the home
office there is a PC (personal computer). It is a ‘lean-forward’ situation where people are
actively engaged with and focused on producing things. The relatively poor uptake of
devices such as WebTV (which provided Internet access through the television) suggests
that neither the lean-forward situation of a PC nor the lean-back situation of a TV in a liv­
ing room will be the right context or the right device for new services such as home bank­
ing, shopping and so on. Instead, a new device, the Home Information Centre, HIC, is
proposed. This should be a device where people can get at and provide information while
they are occupied with other household activities. The industrial partner characterized
this as ‘a move-around situation for infotainment’.

Infotainment is a term intended to convey a mixture of information and entertain­
ment and is one example of how traditional activities and technologies are increas­
ingly converging. Other terms such as 'edutainment' (education and entertainment) and
'infomercial' (information and commercial, or advertising) are increasingly common.
Technologies similarly converge: a phone and a camera, for example, or a PDA and an
MP3 player. One of the challenges for interactive systems designers is to understand
when and where it is appropriate to converge technologies. Is it better - simpler, more
convivial, etc. - to put technologies together or is it better to keep them apart in sepa­
rate devices?

_____________________________________________________________________ t

The project was established to explore the concept of an HIC to see whether full-blown
manufacture of such a device was sensible. There were many parallel activities going on
in the project to do with issues such as market analysis, hardware costs and so on. There
were also many other aspects of the whole software system that were investigated by
different partners. In this chapter we focus on the initial design of the overall concept
and on the key features of the user interface and human-computer interaction.
The abstract concept of an HIC as a device to deal with ‘a move-around situation
for infotainment’ was initially translated into a number of high-level features and func­
tions. The HIC would need to employ software to address the problems of complexity,
difficult navigation and query formulation that bedevil the Web and other large infor­
mation spaces. Two key features were required: an intuitive navigation support system
and a flexible query system. The software should provide the following:
• An abstract representation of the contents of information sources that should be
extracted and maintained semi-automatically
• Speech, pen, touch and keyboard as input
• Sound, images, text and animation as output
• Speech recognition (SR)
• Natural language (NL) queries
• An intuitive user interface.

Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems

The industrial partner on the project who was most likely to subsequently build and
market the device also imposed a key constraint on the project: the HIC should not look
or behave like a PC. They were keen to explore alternative interface designs in the pro­
ject - particularly having a design that did not include scrolling or window manage­
ment. This was a tough design challenge.
The development approach that was adopted was based on the iterative model of
design activities (see Figure 3.1), beginning with mock-ups and ‘Wizard of Oz’-style
experimentation and finally ending with experiments in real homes. The project plan
specified that the HIC would be developed as a series of prototypes, leading to a final
pilot-like complete system. Four prototypes were planned:
1 Prototype PO should be delivered by the end of month 6, and was to be used for the
very first ‘discount’ engineering experiments with the HIC system to aid in the design
specification. PO would not contain software.
2 Prototype PI would be delivered by the end of month 13, and would be used for the
first laboratory experiments collecting data on usage, including interactions and
usage of the natural language query system. The prototype would include full moni­
tor set-up in the laboratory, a PC simulating the HIC client, the content server, a first
version of the display visualization, a simple interaction model, a control module
and simple or dummy versions of the other modules. An operator at the PC (hidden
from the user) would start computer actions requested orally by the user, but not yet
handled by the software (the Wizard of Oz approach).
3 Prototype P2 would be delivered at the end of month 19 and used for full laboratory
experiments at first and then in real user homes. The prototype would be used for
the final user validation of the HIC and its associated concepts. This prototype would
include full monitor set-up, including a PC running the client modules and connected
to a second PC running the server modules. All modules should be present in full.
The prototype would be improved according to the laboratory experiments and the
user site experiments.
4 Prototype P3 was to be the final official version of the HIC, usable for demonstrations
and for the possible basis of further exploitation. It would correspond to P2 but with
corrections and enhancements made following the experiments.
It is fair to say that this was an ambitious plan and the project did not succeed in fol­
lowing it in detail. With so much new technology and so many ‘unknowns’, there were
always going to be difficulties. Indeed, in the end two P3 prototypes were produced one for the functionality of the system and one for the interface concepts. They were
never robust enough to be used in people’s homes.

Challenge 6.1
Discuss the development approach taken.



Scenarios for the HIC

As we have seen (Chapter 2), a useful structure for thinking about interactive systems
design is the PACT approach: people, activities, contexts and technologies. This can be
used to help think about conceptual scenarios of use. Conceptual scenarios are abstract
descriptions of the PACT elements in some domain. For the HIC design, we brainstormed

Chapter 7 discusses the
Wizard of Oz approach


Part I • Essentials of designing interactive systems

-» Information spaces are
discussed in Sections 18.2
and 18 3

ideas at a number of internal workshops about how the HIC might be used. We finished
up with three general, highly abstract uses for the HIC - informational, communicational and entertainment. Early ideas about communication centred on how the HIC
might be used as a sort of ‘Post-it’ system. One member of the family might leave a mes­
sage for another to buy cat food, get some milk or whatever. The HIC would also be used
as a video phone and an e-mail system, and for social networking.
The informational scenarios concerned activities such as finding a recipe. This in
turn leads to ‘What’s in the fridge? What else do we need? What can we cook?’ The HIC
would be able to calculate the quantities in a recipe for one, two or three people. Other
scenarios concerned activities such as going sailing, hence the need to get information
on the tides, going skiing (finding out about the weather), going out (getting informa­
tion about pubs, restaurants and concerts), etc.
The entertainment scenario led to ideas that users might like to play a game, find
some sport, watch TV on demand or automatically record preferred programmes. It
would be possible to have a chat room running alongside a TV programme and so on.
Other scenarios included integration with other devices, such as heating control,
home security and so on. Children doing homework was another, investigating, finding
out, doing crosswords and quizzes, ordering videos, photographs and surfing the Web.
Often the issue came back - how to accommodate large amounts of data, large visuali­
zations, and the multitude of media that would be needed. Remember that the project
was exploring a new device - a home information centre - which was not to be a PC. It
was to be different in its look, feel and usage.
In developing the various, more concrete versions of the abstract activities, we were
aware from a high-level PACT analysis of the need to cover the different people - children,
people with disabilities (e.g. arthritis, short-sightedness), as well as the young and wealthy
who would be the early adopters of such technology. We also needed to cover a variety of
domains and information spaces - e.g. those with rapidly changing information against
those with static information, different media such as maps, voice, sound output and so
on. Eleven scenarios constituted the final scenario corpus that was used in the project:

What shall we have for dinner?
What shall we do now?
News and e-books
Entertain me
Message board
New users
I cannot get my phone to work because . . .
Planning ahead.

Challenge 6.2
Take one of the scenario ideas above, undertake a PACT analysis and brainstorm how the
scenario might unfold.

Note that no decision has been made as to how to deliver these scenarios as yet. The HIC
could be an integrated platform designed specifically for the ‘move-around infotain­
ment’ context or it could be an open platform in which third-party producers would

Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems


develop apps. The aim was to explore the concept of the HIC first before settling on
the physical design. The scenario corpus constituted the first prototype, PO. We were
reluctant to fix too soon on a physical design, being wary of early ‘design fixation’, and
felt that it was much better to explore contexts and activities of the HIC at this point. In
thinking about scenarios of use for the HIC, we were aware that we needed a suitable
variety of domains, interaction styles, media and modalities, people and contexts of use.
One way of learning more about how people might use such a device as the HIC
would be to undertake naturalistic studies of people using existing media in their ‘info­
tainment’ activities. However, at this early stage in the project we were under consider­
able time pressure and hence the opportunity to gather real stories of use would have to
wait. Accordingly, we began by identifying some conceptual scenarios.

Home technologies
Subsequently we did undertake such studies of people and technologies in their homes
and this led to a number of interesting findings regarding technologies in the home and
how people use them within the social and physical spaces. A special issue of the journal
Cognition, Technology and Work (volume 5, number 1, May 2003) is devoted to home
technologies and includes a description of these findings. Baillie and Benyon (2008)
describe a method for investigating technology in the household, the Home Workshop.


A future workshop
One important thing about developing prototypes is using them. The scenario corpus
was used internally within the project team to generate ideas and discuss the details of
functionality. The scenarios were also taken outside the team and used as the basis of
‘future workshops’. Future workshops are one of the design methods advocated in the
participative design approach to the design of interactive systems. This approach has a
long tradition, particularly in Scandinavia, going back to the late 1970s.
A future workshop comprises three stages:

See Section 7.2 on
participative design

1 Critique. This is a group brainstorming session that tries different approaches to the
activities/problems being addressed by the proposed system. A set of themes arising
out of this stage is used in stage 2, fantasy.
2 Fantasy. The emphasis here is on creative solutions/ideas, no matter how unrealistic.
From these a number of fantasy themes are generated and these are then used to
drive stage 3.
3 Implementation. The groups work out what would be necessary in order to produce a
real solution to some of the fantasy themes generated (e.g. by producing a mock-up
or a storyboard).
Using the ‘What shall we do now?’ scenario as a basis (see below), we spent a morn­
ing working with four groups of high-school students through these three stages. The
scenario was supplemented with introductory presentations and written materials and
adapted to make it more relevant to the participants; the students were asked to imag­
ine that they and a group of friends had won a trip to the city for the day and had to plan
their activities.
The results of this session were quite telling. The group focused on the need for the
HIC to be personalized. They wanted mobility in the system and they emphasized the
communication function over the informational function of the HIC.

The prototypes from this
are presented in Chapter 8


Part I • Essentials of designing interactive systems

A more concrete scenario
At this stage in the project it was important to pick one of these scenarios to orient the
various project teams around (ultimately, more fully detailed versions of the scenarios
would drive specification of the HIC interface). We suggested that the informational
scenario ‘What shall we do now?’ was the best one to start with because it covered
lots of different data types which would help all the project partners. A key feature of
the scenario-based design approach that we were following was that all partners in
the project would be required to use the scenario and they would need appropriate
data to work with. There had to be data for the people doing the data mining, data for
the people developing the interface, data for the speech recognition people, and so
on. Additionally, the ‘What shall we do now?’ scenario covered various types of people
(young/old, etc.) rather well. Another of the informational scenarios, ‘What shall we
have for dinner?’, was far less applicable to children, for example, and we saw chil­
dren as potentially significant users of the HIC. The range of activity types (finding
out something, communicating with others, booking tickets online, etc.) in the sce­
nario also provided the opportunity for a variety of interaction possibilities to be inves­
tigated. The remaining scenarios would allow us to investigate other data types (e.g.
pictures/video), use contexts (e.g. hands and eyes occupied elsewhere), activity types
(e.g. games, controlling another device such as a TV) and input/output devices not
covered in the first scenario.

Developing the scenario

<- See Section 3.2 on
personas and scenarios

At one of the workshops, one group took the ‘What shall we do now?’ scenario and dis­
cussed it in more detail. The extract below is taken from the notes of this meeting and
gives an idea of how the scenario discussion generated ideas and questions. The overall
context for the scenario was the large arts festival that takes place in Edinburgh every
August. It was envisaged that the HIC would be an ideal device for finding out what was
going on so that people could decide ‘What shall we do now’.
Early on there was a need to make it more concrete, to focus on a specific context
of use. The discussion at the workshop switched rapidly between high-level concerns
and the details of a concrete interaction. This also resulted in the development of more
detailed personas. It is summarized below.
1 The couple should be aged 20-30. They lived in Edinburgh. It was August and the
Edinburgh Festival was in full swing. The couple knew about the Edinburgh Festival
and wanted to check out what was on that evening. They did not have much time.
2 What sort of a query would they enter? Broad categories of shows such as ‘comedy’,
time constraints such as ‘starting after 6 pm’, specific artists or shows or a specific
venue (because a venue might have a particular specialism)?
3 What would be on the HIC? For example, would there be text only, or pictures/
icons? Would there be advertising? Would people enter a free-form query or browse
through an online catalogue? This was an issue that the content or service provider
would need to deal with. If this is the case then set-up issues are raised. Perhaps
people would select a favourite provider, then they would need to be able to add
and remove them.
4 The modality of the input was considered. Would the HIC have handwriting recog­
nition? Should it be an iPad or tablet PC? Should there be voice input for free-form
queries, a keyboard, remote keyboard or on-screen keyboard?
5 Once the name of the actor/venue, etc. had been input, people would get some dis­
play on the HIC which was dependent on the number of results of the query and the
list of categories. Would the categories be generated automatically, or be preset?

Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems

6 Queries would need a response time of 5-10 seconds. People would make a selection
‘check out show times’- perhaps by touching an icon, perhaps by saying ‘show times’.
They might be using a remote control - how far could the person be from the screen?
7 Once the HIC had displayed the show time, venue, names of actors, any reviews
of the show, etc., the person might want to make a booking. The display would be
dependent on the history of the interaction and the visualization of the query his­
tory (or at least this should be accessible). Then all the issues of how to go back, up,
etc. through the interaction history would need to be addressed.
8 The booking of tickets would probably require a different service or content pro­
vider. Would the HIC then ‘lose control’ of the interface or could the HIC provide its
own to someone else’s (e.g. the Festival Theatre’s) website and online booking facil­
ity? How would the person input their name, credit card, address, etc.? Preferably
this would be automatic.
9 Would the HIC be able to show the number of seats remaining for a show? Would
the tickets be printed on a local printer? There was a need for a function of the HIC
that automatically kept people informed of a changing situation: an interface agent
perhaps, or just part of the interface?
10 The brainstorming continued - what if there was a need to contact friends about the
show, send them details of the location, etc.? They might want to meet for a drink
nearby - in which case, could the HIC access a webcam in the pub to see how busy
it was?
11 Issues of traffic then arose. How long would it take to get there? What about provid­
ing bus or taxi information? The need to have the HIC provide a map or print instruc­
tions was recognized - and this should be able to happen from different locations.
12 The group changed the context to explore other areas such as going skiing or sail­
ing, but apart from the issue of scale - the information space of skiing is much larger
than the information space of the Edinburgh Festival - few new issues arose. How to
update the service or content providers was important and there was some discus­
sion about security, personalizing the HIC, etc.
The results of these discussions were taken away from the workshop and put alongside
some real data from the previous year’s festival. Flyers for shows, brochures advertis­
ing events and the details from the whole Festival programme were used to provide
real examples of the sort of data that the HIC in this scenario would have to deal with
(Figure 6.1). The final version of the scenario is shown in the next section.

The Edinburgh Festival scenario
The ideas that had been developed finally finished up as the scenario shown below.
Although it is quite concrete, with some interface features described and a wealth of
context, there are many design features that have not been agreed. These are recorded
as footnotes to the scenario. One of the features of the design method is that these foot­
notes force the designers to consider further design issues. The scenario below illus­
trates the recommended formal way of presenting scenarios.
Scenario name
What shall we do now?
Scenario history





20 April 2009
4 May 2009

D. Benyon
D. Benyon

Discussed at Struer meeting
Modified following discussions at Struer



Part I • Essentials of designing interactive systems

Figure 6.1 Example flyers from the Edinburgh Festival
(Source: David Benyon)

Scenario type
Activity scenario

People - young, wealthy, no children
Activities - searching for information, making bookings, meeting friends
Context - flat in Edinburgh, assume fast Internet connection
Technology - HIC as currently specified.

This scenario has been developed as part of the prototype PO deliverable. It is intended to
provide a rich description of a general context of use of the HIC. The scenario is deliberately
vague with respect to a number of features such as input and output media and modalities,
how the content is provided, etc., in order to stimulate discussion about such things. More
concrete forms of the scenario are expected to be produced to illustrate a range of media/
modalities. The scenario is also intended to provide a rich source of data so that issues con­
cerning the semantics of the information space may be considered.

1 Jan and Pat are a couple in their mid-thirties. Pat is a university lecturer in Cultural Studies
and Jan is an accounts manager at Standard Life insurance. They live in the Stockbridge
area of Edinburgh in a two-bedroom flat overlooking the river. It is 12.00 noon on
15 August. Jan and Pat are sitting in their large, airy kitchen/dining room. The remains of
pizza and mixed salad mingle with a pile of newspapers on the kitchen table. Jan and Pat
have recently returned from a holiday on the island of Zante and, apart from checking
their e-mail, have not gone back to work. They decide that they would like to go to see
one of the events that is happening as part of the Edinburgh Festival.
2 The Edinburgh Festival is a large arts festival that takes place in the city for three
weeks in August. It consists of two arts festivals - the Edinburgh International

Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems





Festival and the Edinburgh Festival Fringe - a book festival, a film festival, a jazz fes­
tival and a variety of related events. The International Festival is the original, and up
until the mid-1980s was the bigger of the two. This is the official festival, which fea­
tures prestigious performers from around the world, world-class orchestras, com­
posers, ballet troupes, etc. The Fringe, on the other hand, started as an unofficial
adjunct to the festival, traditionally more informal and adventurous. It featured new
theatres like the Traverse, or the work of artistic mavericks like Demarco. Gradually
over the years it has become larger than the official International Festival. In total
the Edinburgh Festival consists of some 1200 distinct events that take place at 150
different venues spread throughout the city.
Jan activates the HIC1 and chooses 'Edinburgh Festival'.2 The HIC connects to the dif­
ferent content providers who are registered as providing content about the festival. The
display shows five categories of information - Times of Events, Specific Artists, Specific
Events, Specific Venues, Types of Events - a catalogue and a query facility.3
'What sort of thing do you fancy doing?' asked Jan. 'Hmmm, something funny, perhaps,'
Pat replied. 'Richard Herring, maybe, or Phil Kay? Stewart Lee? I guess we ought to check
out the International Festival aswell.'Jan entered the query 'What do we have for Richard
Herring, or Stewart Lee?'.
The HIC displays Excavating Rita, King Dong vs. Moby Dick and This Morning with
Richard not Judy II4 along with a display5 of categories of further information: TV
Reviews, Newspaper Reviews, and Times of Events.6 Jan makes the selection7 of
Times of Events. The HIC responds with details of the events it has retrieved, dis­
playing the data Title, ShortDescription, Venue, FromDate, ToDate, ExceptDates,
Days, StartTime, Duration, Cost, ConcessionCost.8 'What do you think?' said Jan.
'Check out Excavating Rita and This Morning with Richard not Judy II,' replied Pat.
'Well, there may not be any tickets left for This Morning with Richard not Judy II, I'll
check.'Jan specifies that the HIC should monitor the number of tickets left for This
Morning with Richard not Judy II.9 The display shows 24 tickets left. 'You had better
check Excavating Rita as well.' 'OK.'Jan instructs the HIC to monitor TicketsLeft for
Excavating Rita as well. The display shows 45. The display highlights that the value
of TicketsLeft for This Morning with Richard not Judy II has changed to 20, then to
18. 'Hmmm, This Morning with Richard not Judy II is selling fast, I don't think we are
going to make that. Is there anything else?' says Pat.
'Well, hundreds of things, actually,’ Jan responded: 'Let's see. At 1 pm we have
'Verdi's Macbeth', a lunchtime talk at the Queen's Hall, or an archive recording of

1 Flow the FIIC is activated is not considered here. Different methods may lead to different versions of the
2 So, 'Edinburgh Festival' is a 'thing' in, or accessed by, the FIIC. It could be some sort of plug-in provided by
a third-party content provider. For example, the Guardian newspaper might provide a free CD-ROM for
its readership, Jan and Pat may have downloaded the data from a website, or the data may be physically
resident on some remote machine, or on Pat and Jan's computer.
3 Again the modality of these are not specified. The query facility could be spoken, typed on a remote keyboard
or an on-screen keyboard, written by hand or in some other form such as a query agent. The catalogue facility
could be represented in a number of different ways.
4 Flow this data is presented is a major issue. We do not know how far our users are from the display.
5 There are a number of issues concerned with things such as response time here. Will the FIIC display some sort
of'busy' icon, provide information on how long the result of the query will take, present data gradually, etc.?
6 There are many possible categories and ways of presenting and interrelating the data. Ideally the categories
will be automatically generated.
7 Once again, modality is not specified - Jan could touch an icon on the screen, say 'Show Times', use a remote
control and click the 'Go' button, etc.
8 See data dictionary for more details about these data items. (Not included here.)
9 This raises the whole issue of agent-based interaction. Will the FIIC have an agent (anthropomorphic or not) or
will it be possible to specify these sorts of things through the general 'intelligence' of the HIC technology? Jan
could instruct an agent to monitor some attribute of the data - TicketsLeft in this case - or the system could
facilitate this type of facility in other ways.

See Chapter 17 on
agent-based interaction



Part I • Essentials of designing interactive systems





Sir John Barbirolli at 2.15. The Nimmo Twins in 'Posh Spice Nude' at the Gilded
Balloon, that's at 1.30. . . .'Jan continues to browse the listings, jumping to read
reviews, watching snippets of TV Reviews, checking times and so on.10 The display
highlights changes in the TicketsLeft for Excavating Rita, now down to 35. At 12.30
the display indicates that This Morning with Richard not Judy II has started. 'Well,
we had better do something,' said Pat. 'Let's go for Excavating Rita and book our
tickets now.'Jan selects Excavating Rita and 'booking' and the Booking Office at the
Pleasance Theatre is displayed.11
The booking form has fields for Name, Address, PhoneNumber, Postcode and
CreditCard type, ExpiryDate and Number. Jan selects 'personal profile' on the HIC,12
confirms that the details should be Jan's, and the data is entered onto the booking
form.13 Just a minute,' says Pat, 'Kat and Toni might like to come. Why don't you check?'
Jan activates the phone14 and selects Kat and Toni.15 The number is dialled and Toni
answers. 'We are going to see Excavating Rita with Richard Herring at the Pleasance.
Do you fancy coming? It starts at 3.30 and there are only 35, sorry 32 tickets left.' 'Sure,'
says Toni, 'We'd love to. I'll come online.'16Jan returns to the booking form and specifies
four tickets. The total credit card amount is calculated and displayed. Jan confirms the
transaction and receives a confirmation number.
Jan sees that Toni is online and changes to the conferencing system that they both
use. Jan enters the message17 that they have the tickets and suggests meeting for a
drink beforehand. There is some discussion about the location, pubs versus restaurants
versus cafes, food or not, etc.18 Toni indicates that the area is not familiar. 'I'll see if there
is a map,' says Jan.
Jan selects the Specific Venues category, selects the Pleasance Theatre,19 and selects
map. A map showing the area is displayed. All the restaurants, cafes, pubs, etc.20 are
shown. Jan selects Pubs and the display changes to remove the other eating and drink­
ing places. The pubs are highlighted and referenced.21 Jan selects three or four pubs
in turn and gets information about the pub type, distance from the Pleasance, etc. Jan
returns to the conference and sends the message to Toni that there is the Pleasance
Courtyard, but it will be packed,22 or the Southsider. It's a 10-minute walk, but it serves
Maclays which is a nice beer.
Toni says that some help getting there would be useful. Jan attaches the map to a mes­
sage and sends it to Toni. When Toni gets it, the HIC at Toni's end is able to provide
instructions about how to get to the Southsider. 'See you in the pub in an hour, then,'
says Pat, 'but you had better get started. I just checked the traffic on the Dalkeith Road
and it’s terrible.'

10 An issue here is how the display builds up and how a trace of the various queries and browsing is presented.
It would or might be desirable to have some way of showing links between artists, shows, venues, type of
event and so on.
11 Note that at this point we have 'gone outside1the HIC and are at the mercy of the Pleasance Theatre's inter­
face design for their booking system.
12 Again this could be a personal agent or other way of providing profile data.
13 This happens automatically, presumably.
14 This is probably part of the HIC, but could be the regular phone, of course. How it is activated is up for debate.
15 By Name from an address book, through their personal profile, or whatever.
16 Or perhaps Toni is automatically 'online' in answering the phone.
17 This may be spoken interaction, it does not have to be typed.
18 Ideally the HIC will be able to pick up on keywords used in such conversations and use these in subsequent
19 Again this would probably be the default given the history of this interaction.
20 As per their conversation, earlier.
21 There's another issue about categories here. Maxine's is categorized as a wine bar, but could ju st as easily be
classified as a pub.
22 Or perhaps looks at the Courtyard in real time through the Pleasance cam.

Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems

Challenge 6.3
Using the footnotes recorded against the Edinburgh Festival scenario, discuss possible
design decisions, or design trade-offs, that will have to be made.



Evaluating early interface prototypes

In order to evaluate some interface concepts, three prototype design solutions, each taking
one of the scenarios as a starting point, were produced. These draft prototype designs were
developed as working solutions to some of the questions that had arisen from three of the
scenarios. This section discusses the three prototypes produced and analyses the decisions
made by the three designers in response to the design of the HIC as a whole. This work then
served as the basis of the development of the second interface design.

Usability principles
The design principles introduced in Chapter 4 were used as a basis for the evaluations.
The principles outline the three main categories of usability that interface design should
encompass and this can provide the basis for an early high-level ‘discount’ evaluation.
This is a high-level “walkthrough’ of a design undertaken by an expert, guided by design
principles. We used our principles of learnability, effectiveness and accommodation.
• Learnability. Can people guess easily what the system will do, based upon previous
experience? This covers the usability principles of visibility, consistency, affordance
and familiarity.
• Effectiveness. Can people correct or change previous decisions, and complete their
desired task easily, effectively and safely? This covers the usability principles of navi­
gation, control, feedback, recovery and constraints.
• Accommodation. Is the system designed to afford a multiplicity of ways in which peo­
ple can accomplish their goals? Is it pleasant to use? This covers the usability princi­
ples of flexibility, style and conviviality.
In order to illustrate this process we report on the evaluation of prototype B which
concerned the issue of presentation of huge amounts of information, which will be
accessible through the HIC. Figure 6.2 shows a screenshot from this draft prototype
illustrating the use of conceptual categories relevant for a ‘festival’ content provider.
An issue at this point was who would define such categories and how many categories
are appropriate. This question continued to be extremely important for the project.
The prototype defines multiple levels of information available through the use of
a colour-coded history top bar. It also provides a solution for the many actions and
operations to be presented on screen only when required, by means of hidden docks.
It deals with the issues involved with utilizing the HIC from a distance in connection
with speech input or remote control with the implementation of ‘Near’ and ‘Far’ buttons
which magnify the contents on the screen.

• Learnability. The interface was easy to follow. The inclusion of ‘hotspot’ rollovers
on certain areas of the interface confirms to the user that these areas are clickable

Expert evaluation is
discussed in Section 10.2



Part I • Essentials of designing interactive systems

Figure 6.2 Prototype B - festivals screen snapshot
(Source: David Benyon)

buttons. The animated arrow at the bottom of the interface indicates that there
is a hidden dock available at the bottom of the screen. When someone clicks on a
button on the main interface and is taken to the next level, their ‘route’ through
the information space is recorded on the history bar at the top of the screen.
The separate levels have backgrounds of different colour to separate them. A prob­
lem here is that they do not correspond to the colours on the history bar, which is
slightly confusing. The history bar contains a group of rainbow-coloured cells that at
some points could be completely empty or contain no history, which could confuse.
The question also arises as to what would happen to the history bar when the person
had gone through more than six pages of information, as the bar has only six cells.
• Accommodation. In terms of flexibility, this interface solution offers people a number
of ways in which to complete the same task. For example, they could search for a par­
ticular event in the Edinburgh Festival, look through a number of events on a certain
date, or look for events in a certain area of the city. People can access previous levels of
information through the history bar, or through the Back button on the hidden navi­
gation bar, but cannot then return to the level they were on without searching for it
again. The Near and Far buttons also provide some kind of solution to the problem of
a small 15-inch screen being viewed from the other side of the room by someone who
is using voice activation or a remote control as a means of operating the HIC. The but­
tons on the screen were also well proportioned for using with the touchscreen facility.
• Effectiveness. The design is fairly successful concerning effectiveness. People are able
to go back to previous levels easily via the history bar or Back button. The design
contains a Forward button, which is non-functional, indicating that it was intended
to be included in the design. However, its functionality is not clear, and what would
the history bar show if people were to go back? How would it indicate that they might
also go forward?

After evaluation this solution provided a great many ideas and questions that needed
answering. Although not perfect, this design gave a good starting point for providing an
effective solution to the many problems that the HIC poses.

Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems

In particular, a history bar was an effective idea, but the colour coordination, repre­
sentation of the bar with no history or huge amounts of history, and representation of
the bar when people are moving backward through the information all needed to be
looked at further.
Colour coordination of the different levels was also a good idea, but it was not really
used to good effect and could be confusing. Used in another way, it could provide a
powerful tool for navigating the HIC’s huge information space. The allocation of colour
to the levels of information needed to be investigated further.
The hidden navigation bar was also an effective idea, and would solve the problem
of a large number of actions or facilities having to be available to the user quickly and
easily without cluttering and confusing the screen. This was also an idea that would be
looked at further.

Challenge 6.4
Put yourself in the place of the industrial partner and offer a brief critique of this
interface. Remember that the company was interested in high-quality, novel, 'intuitive'
user interfaces and escaping from the PC look and feel.

...... -...................... ........... ......

-- ---- ----- ------- ------------- J

Outcome of the evaluation
The outcome of this evaluation, taking on board the industrial partner’s comments and
the views of the design team, is set out in Table 6.1. The activity was very beneficial in
highlighting some key interface design issues. In Part III a number of design features
that build upon these concepts are illustrated.
Table 6.1 Outcome of the evaluation
Problem or issue

Suggested solutions

History of navigation ideas need to be developed

Use of animated rectangles, utilization of partner's
remote-control button shapes, recording the user's
path, providing a bar along the top of the screen,
or recording the direction of navigation

Utilization of colour to categorize the huge amount of
information stored within the HIC

Define categories and subcategories within the
information space and allocate colour accordingly

Attention needs to be paid to the multimodal element

All design decisions must accommodate the multimodal
element. Text must be readable from a distance, and
any selections regardless of mode of input must confirm
user interactions

Separation of the various navigational aspects

Navigational elements must be organized according
to definable groupings. Navigation should be available
as needed; hidden docks could be used for those least
utilized so as not to clutter screen

Formalization and order of the functionality of the

The actions and activities, as well as the information
which needs to be navigated, have to be ordered.
Generic actions of the system must therefore be

Utilization of the industrial partner's design concepts
where possible

Existing style and design of remote controls could be
integrated into the design



Pari I • Essentials of designing interactive systems

6.4 A first design
Having evaluated the existing prototypes, it was evident that before finalizing any
design ideas it was necessary to understand the HIC and the generic actions of the sys­
tem. That is, it was important to establish some high-level functional requirements:
what the system had to do. As we discuss in Chapter 9, a good method of establishing
requirements is to undertake an object-action analysis of the scenarios.
The idea in doing this analysis was to acquire a more in-depth understanding of
the HIC. By identifying the activities, actions and objects within the scenarios it was
hoped to give an outline of the potential utilization of the HIC. By listing these activi­
ties, it also gives an indication of how often particular activities and actions could
be carried out and how many objects require being present on the screen at the
same time.
The initial object-action analysis resulted in four categories of object:
• Information display objects - display-only data which has been searched for or
queried. The data is non-editable and provided by content providers, etc.
• Category objects - includes lists and catalogues, changeable dependent on the
providers that are subscribed to on the HIC. Restrictions or enhancements may also
be applied to individual users’ preferences.
• Functions/control objects - controls and tools which are basic to the HIC and enable
functionality of the system, i.e. preferences, payment, set-up, etc.
• Physical objects - devices which are displayed on screen or controlled by the HIC.

v rSection 9.4
. . gives a detailed
,. ,
example of object-action

Details of the objects and actions in the different categories were extracted from all the
scenarios, not just the Edinburgh Festival scenario. From the data collected through
an analysis of the scenarios, a list of the actions was made, with a count of the number
of times these actions occurred in the scenarios. This helped to identify repetition in
actions, actions that represent a series of actions rather than singular actions, and any
actions that are performed by the system rather than by the user.
Three iterations and consolidations of the actions were undertaken. For example,
‘Answers’, ‘Enters’, ‘Writes’, ‘Inputs’ and ‘Specifies’ in the context of the scenarios all
describe the action o f ‘inputting’ information into the HIC in a varietyJ of modal forms.
The action ‘Inputs’ therefore best describes the generic action performed. Table 6.2
shows the results of this process.

Table 6.2 Simplification of the data - stage 3
A ction


A ction




Confirm s





















Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems

Conceptual design
The results of the analysis of the scenarios and evaluations of the early interface pro­
totypes resulted in a number of conceptual and physical design decisions. A number
of important decisions were made, including the concept of a category bar described
below. Notice that although the design is primarily conceptual at this point (i.e. we are
concerned with what is required rather than how it will look and behave), it is natural to
undertake some physical design as part of this process.

The category bar
The wealth of information that was going to be included in the HIC, probably from
third-party content providers, had to be categorized to give it some form of order.
In interface prototype C (Recipes, not included here) the designer had utilized catego­
rization to develop four headings in the history. These categories now needed to be
looked at further. The designer had listed ‘work’, ‘household’, ‘email & web’ and ‘enter­
tainment’. However, it was not clear why these were chosen, nor how they related to
the general domains in which the HIC would be used. The use of the standard terminal
colours - red, blue, yellow and green - was liked by the industrial partner, and these
seemed to be the most effective colours to use in categorizing the information. This
meant that all domains would have to be grouped into four categories. The domains
listed in the scenarios were as follows:
Travel Planner
Find a Place
TV/Radio Programmes
On-line Shopping
The following categories were defined from this list:

Culture - includes the Culture and TV/Radio Programmes domains.
News - includes the News domain.
Household - includes the Recipes and On-line Shopping domains.
Travel - includes the Travel Planner, Traffic and Find a Place domains.

Each of the categories listed above was now colour-coded and represented as buttons
on a bar, as shown in Figure 6.3. To aid association for people, the information con­
tained within these categories would also incorporate the colour chosen to identify that

Figure 6.3 Colour-coded category bar



Part I • Essentials of designing interactive systems

An interface design
The various design ideas were then brought together into the first comprehensive inter­
face prototype. The category bar and a history bar were devised to occupy the top part
of the interface, and the navigation controls needed to be central for people to get easy
feedback whilst utilizing the system - an important design principle.
An idea of all the control being allocated to the border of the screen meant that the
two sliding hidden docks containing the functions and auxiliary objects (such as access
to the TV, radio, PVR (personal video recorder), etc.) were placed to the left and right of
the screen to slide out when needed (see Figure 6.4).
The idea of the sliding docks was a good one, but the two slide bars intruded some­
what into the main space. There was also the possibility of applying all of these objects
to one location rather than splitting them up into groupings. This was another idea
worth mocking up. However, when it was designed an immediately obvious problem
was its use of pop-up menus that were not intended to be used within the HIC interface,
as they are too reminiscent of a PC interface.

Figure 6.4 First layout with hidden docks

Evaluation of first solutions
These designs were brought back to the main interface design team who met and dis­
cussed the ideas. The group was not sure about the categorization of objects. One of
the designers suggested that the activities Search and Print, which were allocated to
the bottom bar, should be grouped at the left side of the interface. This seemed a much
more coherent separation of the objects. He also suggested that the right-hand bar
could include the lists of the content providers subscribed to on the HIC. This would
allow people to click on an activity, for example Search, and then to click on a content
provider, such as the Scotsman, and search the Scotsman information space. A sketch
produced at this meeting is shown in Figure 6.5.
This design decision turned out to be fundamental to the HIC concept. The separa­
tion of objects and actions and the provision of a central information space was felt to
provide a clear and simple conceptual model: objects on one side and actions on the
other. Such a simple and clear model should go a long way to ensuring that the interface
was ‘intuitive’.

Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems

The question then arose of what to do if there are lots of content providers that
the HIC owner subscribed to. How could they be shown on a bar without the use of
scrolling of lists? The use of a rotating bar was suggested to deal with this. A number
of alternatives for the side bars, finally resulting in two spinning ‘Toblerones’ that
were also hidden docks (the activity and provider bars on the left and right), was
the next stage of development (Figure 6.6). The bottom navigation button was also
After development of this prototype it was realized that the idea of a three-sided
Toblerone would allow the category bar to have a menu on one side which lists the
domains within that category for people to choose from. This would mean that when
someone clicks on a category, the bar could spin to reveal a menu. With three sides,
the category bar could still have the history on one of the sides. Instead of the his­
tory bar being only relevant to the category the person was looking at, the bar would
show the history of all the pages the person had visited within all of the categories. For
example, it could show two blue arrows from the Travel category, one from the yellow
News category, a red search arrow from the Culture section and a green arrow from
the Household category. The necessity of this bar to be available on screen at all times
meant that this bar would not take the form of a hidden dock.

Figure 6.6 Opening HIC sequence showing two 'Toblerones'



Pari I • Essentials of designing interactive systems

6.5 The second interface design
A number of changes were made between the first and second interface designs. These
included changing the categories of actions on the left-hand bar and dropping the
bottom bar altogether.
One important concept to arise from the first prototype was the idea of a history.
Previous queries could be displayed on the screen, gradually disappearing into the
distance as they got older. Another member of the design team began to look at this and
at the overall concept of searching. The initial ideas for having a novel searching inter­
face had been developed and critiqued over a long period. A number of the relevant
sketches are discussed in Part III.
The final design was based on the concept of a ‘Rolodex’ (Figure 6.7 shows a sketch
of the idea). This design avoided the PC-centric design feature of having scrolling
windows with all the concomitant window management activities and we felt that it
was a more engaging design, suitable for a relaxed home environment. The concept
behind the finalized Rolodex is such that the user may ‘flip’page by page through results
until the required item is found. This is done by simply touching the ‘Prev’ or ‘Next’ icons
to the left of the Rolodex or by using a ‘flicking’ gesture on the cards. At any stage the
user may select an item by touching the page of the Rolodex or by selecting ‘Go!’.
Bringing together the concept of history and the concept of the Rolodex resulted in
the idea of having a history of previous searches represented with smaller Rolodexes.
When the person selects ‘Go!’ an animation of the Rolodex shrinking in size and mov­
ing to the bottom left-hand corner of the screen is provided. A new Rolodex is pre­
sented with the items relevant to the previously selected item, and searching through
the information may be performed in exactly the same manner with the new data.

Figure 6.7 Second interface prototype

Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems

Figure 6.8 Rolodex history and Rolodex tree

One further concept was added. If any category of the search returns more than 20
results the system then presents the person with a number of Rolodexes (Figure 6.8 illus­
trates this). Another version was based on the idea of a cone tree (see Section 12.5).
In this case the Rolodexes are categorized alphabetically and any miniature Rolodex
may be touched for selection. This then fades the display and a new full-size Rolodex is
again presented with the information contained in it.
Once the required item has been found, the page of the Rolodex is pressed to see
the article in more detail. An expanding page appears from within the Rolodex, looking
like a card from a card index in order to maintain the visual metaphor, offering a com­
plete description of the item selected (Figure 6.9). To return to the items in the Rolodex,
the user would press the small Rolodex titled ‘Items’ at the top-left corner of the screen.

Figure 6.9 Result of search displayed as 'index card' from Rolodex

Scotsman, August 1998)



Parti • Essentials of designing interactive systems

Evaluation of the second prototype
The second prototype embodied a number of key concepts that would now have to be eval­
uated with some real people. Designers can only come up with their best ideas. As soon as
these are in a coherent form, they need to be evaluated with potential users of the system.
A full working visual prototype from which the screenshots in Figures 6.8 and 6.9 were
adapted was developed. This included a real database of articles from the Scotsman news­
paper on the Edinburgh Festival so that people could undertake real searches.
As with the rest of the case study, the evaluation process is not presented as a perfect
model to follow, but rather to stimulate discussion of the approaches used. The evalu­
ation was aimed towards the key areas of the interface. In this case the designers were
particularly interested in:

System learnability. Does the design of the interface help or hinder people?
Toolbars. Was animation of toolbars effective? Overall concept good?
Icons. Are they understandable? Is their meaning obvious?
Logos. Are the content provider logos effective as identifiers?
Rolodex. Is the general concept of the Rolodex liked? Is it effective? Does it facilitate
• Categorization. Is breaking down the search into categories an effective means of
• Consistency. Is the system consistent?

Questionnaire design is
covered in Chapter 7

A questionnaire was developed to deal with each of the above areas. It included 20 state­
ments for which people could choose from 1 (meaning strongly disagree) to 5 (strongly
agree). The questionnaire is explained in Table 6.3.
Questions were mixed - some were expressed in a positive fashion and others in
a negative fashion to prevent people simply ticking all the strongly agree or disagree
boxes; they had to read and think about each question. A section at the start of the
questionnaire established the background of the participant. A further list of three
open-ended questions was included at the end of the questionnaire. A comment box
was also included for additional suggestions that evaluators could make.
The evaluation took place in a vestibule area of the university where many people
were passing. A physical prototype of the HIC with a 15-inch touchscreen monitor
set into a portable television-sized MDF (medium-density fireboard) casing was pro­
grammed with the sample data.
Potential evaluators were approached for their assistance and then taken through the
main functions of the HIC. They were then given a concrete scenario to work through
in which they were to find a performance from the previous year’s Edinburgh Fringe
Festival, read an article on it and hence decide if they wished to go and see the show.
The evaluations took around 10 minutes each. A total of 50 evaluations were completed
over two days.

Evaluation results
Just a few of the results are explored here. The bar chart (Figure 6.10) outlines the
responses to each question: whether the person agreed with the question, disagreed with
it, or was indifferent (neither agreed nor disagreed). ‘N’ indicates a negative question,
hence if a high proportion disagree it is a good design feature. ‘P’ indicates a positive ques­
tion, hence if people agree this is a good feature. The assumption was made that if a per­
son chose agree or strongly agree, then the response was classed as agreeing with the
question. If a person chose disagree or strongly disagree, then the response was classed
as ‘disagree’. This method filtered out all the halfway votes that may have influenced the
answer unfairly.

Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems

Table 6.3 A brief explanation of the questionnaire


Question: concept

Question: design





To evaluate system
as a whole

Do users like the system? Do
they find it easy to use?




Is system

Is design too cluttered or



System should be easy
to learn

Does design of
interface help or
hinder user?

System is designed with ease of
use uppermost. These questions
will give important feedback on
this issue



More than one way to

Rolodex or content
provider logo: any

HIC allows user to search for
information in more than one
way. Will user even realize this?



Animation, i.e.
movement idea, sides

Arrows too big or
small, colour

Aim: to try to cut out scrolling



To do away with text

understandable and
meaning obvious?

Icon meaning may be
ambiguous. Do people readily
understand them?



Use of pictures to
symbolize company

Colour, font,

Aim: to cut out writing and
associated problems; to make
content providers more



Touch as in feel,

Design facilitates
use of touchscreen

Aim: to reduce amount
of peripherals (mouse,
keyboard, etc.)

used by the


Colours should be
pleasing to the eye,
and for categories map
onto colours on remote

Aesthetics: shape,

Will people like very basic
colour used? Makes the design



Helps user visualize size
of search

Shape, size,
legibility of Rolodex

To make searches more
interesting and help user
visualize amount of information
returned by their search criteria



Quick way to search,
without having to be
too specific

Category names,
e.g. culture,

To let user search without
having to put in specific search
criteria. Aim is also to show
some kind of history



Design should be
conceptually and
physically consistent

mechanism, colours

Also external consistency


It can be seen through this chart that in general all responses were of a positive
nature. Some aspects of the system were more positive than others. The data was used
for a number of related evaluations. The aspects that this evaluation focuses on are in
particular the use of Rolodexes for searching, the Rolodex tree, the categorization of
data and the general ease of use of the system.



Part I • Essentials of designing interactive systems













1 2

















I l_l





m 1-------1-------1-------1

7 8
9 10 I I 12 13 14 15 16 17




Q u e stio n num ber
A g ree


[ ^ ] D isagree

Figure 6.10 Overall results from the questionnaire: averages over 50 evaluations

Results indicated that a general liking was found for the Rolodex concept, although a
significant minority felt quite strongly against it. A few negative comments were as follows:
• ‘Rolodex too slow, no way to jump through lots of data . . . ’ (Questionnaire 34)
• ‘should be as life-like as possible (putting in markers, taking out cards, leafing
through them)’ (Questionnaire 36)
Some positive feedback was as follows:
• ‘Very intuitive’ (Questionnaire 38)
• ‘The Rolodexes and menus were very good for browsing’ (Questionnaire 41)
• ‘The Rolodex idea is very good. Selection of alphabet would improve it.’
(Questionnaire 10)
The question that asked whether the Rolodexes helped gain an overview of the informa­
tion available was posed and the outcome is shown in Figure 6.11.
Through a study of the many comments made regarding the interface by those who
took part in the evaluations, it was clear that the first prototype was quite successful and
that many of the main concepts of the interface were worth pursuing. Areas of improve­
ment and amendment are necessary, in particular:
• Larger arrows. At present the arrows on the toolbars are too small for convenience.
• Markers. A point made by many was that a marker system should be introduced to
the Rolodex, i.e. some way of holding a page of the Rolodex. Perhaps have a colourcoded tag at the side of the page of the Rolodex.

Figure 6.11 Overall response to question whether Rolodexes helped gain an overview

Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems

• Alphabetical search. It was suggested by a few that displaying an alphabetic search at
the top of the Rolodex would be a good idea. This would save searching through each
individual item one by one.
• Order of colours for category buttons. To conform to a standard they should be red,
green, yellow, then blue.

Challenge 6.5
C r it iq u e th is e v a lu a tio n . W h a t d o y o u t h in k is g o o d a b o u t it? W h a t c o u ld h a v e b e e n


im p r o v e d ?

Summary and key points
In this case study we have focused on the interface design for a novel device - the Home
Information Centre. We have deliberately left the discussions much as they were during
the design process so that you can see how discussions move, fluctuating between very
detailed concerns and very high-level or conceptual concerns. We have not 'tidied up'
the process. Much of what is in this chapter has been taken from reports that were pro­
duced at the time. What we have tried to do is to tell a story of a design, the key points
• How scenarios were developed to explore the design space of the HIC device
• How the scenarios were analysed in order to understand the main functionality the
device required
• How the key design concepts were developed through prototyping ideas, evaluating
them and redesigning them
• How key design concepts were realized physically and how the physical design
affected the conceptual design and vice versa
• How a physical design was evaluated, focusing on some key aspects of the design.


A n o th e r th o rn y prob lem th at a d e vice such as th e H IC creates is the issue o f
filin g , sto rin g an d retrie vin g d ata, w h e th e r th ese a re e -m ail m essages, M P3
files, photos o r o th e r o b jects. C o n sid e r h o w to design an effective filin g system
th a t does not req u ire peo p le to u nderstan d and use a h ie rarch ical system such
as on th e M ac o r PC th at uses files and fo lders.


D u rin g this p ro je ct w e also investigated h o w to p ro vid e good access to all
th e co n te n t th at peop le w o u ld be accessing. W e co n clu d ed th a t th ere w o u ld
alw ays be a need fo r co n te n t p ro vid ers to m ark up co n te n t aim ed at a sp e cific
au d ie n ce . Ju st as new s is repo rted in m an y d iffe re n t w ays, so all the HIC's
co n te n t w o u ld co m e from su b scrib in g to a co n te n t provider. D iscuss w h a t
a co n te n t p ro v id e r m ight o ffer and w h a t th e business m o del m ight be fo r
p ro vid in g this service.




Part I • Essentials of designing interactive systems

Further reading
There are not many books that provide good case studies of doing interactive systems design
and it is difficult to get at papers reporting designs. The proceedings of the ACM Designing
In te ractiv e System s (D IS ) co n fe ren ces do contain some design cases and it is also worth
looking at the CH I series o f co nferen ces for design cases. Both are available from the ACM
digital library.

Getting ahead
M ayhew , D. (1999) The Usability Engineering Lifecycle: a Practitioner's Handbook for User
Interface Design. Morgan Kaufmann, San Francisco, CA. This is a comprehensive book on Mayhew's
commercial approach to ensuring usability in systems. See also Mayhew and Follansbee (2012).
M oggridge, B. (2007)

Designing Interactions. MIT Press, Cambridge, MA.

Designing for Interactions Creating Smart Applications and Clever Devices,
New Riders, Indianapolis, IN.

Saffer, D. (2009)
2nd edn.

The accompanying website has links to relevant websites. Go to

Comments on challenges

Challenge 6.1
The overall approach was sound, but turned out to be far too ambitious. There was planned prototyp­
ing and evaluation was central to the approach (see Chapter 3). It adopted a scenario-based design,
with PO being a corpus of scenarios. Developing scenarios and prototypes allows for consistent and
early testing with real people. The Wizard of Oz approach allowed us to simulate technologies before
they had been developed.

Challenge 6.2
Of course, you will have chosen different examples, but you should have thought about the variety
inherent in any of these scenarios. For example, the 'What shall we have for dinner?' scenario might
• People - a young girl with her grandmother who is visiting for a while
• Activities - investigating recipes, finding out what could be cooked with the food that is in the
house, dealing with allergies to particular foods and finding alternatives, finding simple or complex
recipes, finding particular types of food
• Contexts - making something quickly, cooking for lots of people, cooking for just one or two
• Technologies - the basic HIC design is a constraint, but there is a need to consider the content
(i.e. information about recipes). Is there a video showing how to make things, are there links to
on-line chat rooms, recommendations from others or from famous chefs, etc.?

Challenge 6.3
There are, of course, many design issues that are raised and hence many design options that can be
considered to deal with them. One issue, for example, concerns how much the system can know
about the different people - e.g. where they live, what the roads are like, how you can travel from

Chapter 6 • The Home Information Centre (HIC): a case study in designing interactive systems

one place to another. Such data is available (e.g. for in-car travel systems), but how the different
content from different providers can be linked together by the HIC is a challenge. There would
presumably have to be some standard 'mark-up' language used, such as XML. This would allow
interoperability between the different applications.

Challenge 6.4
The menu bar or 'history' bar was thought to be a good idea, although the text on the buttons was
unclear. The use of colour in the 'history' bar was ineffective, as was the presence of all of the but­
tons when they had no labels. Use of highlighting of the main screen buttons obscured the text.
The animation included in the arrival of the hidden dock on screen was very much approved of,
and was seen as a device which should be looked at further.
The organization of buttons in a semi-circle around a topic was liked as a concept for the organ­
ization of information and would interpret well for use with the touchscreen. The idea of the Near
and Far buttons was a good one. The interaction was felt to be too spread out all over the screen.

Challenge 6.5
The evaluation was quite effective, though probably could have been better. All too frequently
these things are rushed near the end, but for its purpose - to get general feedback on the inter­
face concepts - it was probably sufficient. Importantly, it was undertaken with real potential users
and there was a good spread of people who used the system. The task was relatively quick to do,
which is important from the pragmatic perspective, and the results provided both qualitative and
quantitative data.


Part II


Techniques for designing
interactive systems

U nderstanding 138

8 Envisionm ent


Design 187

10 Evaluation 214
11 T ask a n a lysis 238
12 Visual interface design 255
13 M ultim odal interface design 288



Techniques for designing interactive systems

Introduction to Part II
The aim of this part of the book is to bring all the relevant techniques for designing
interactive systems into one place. Part I introduced the key processes that are involved
in designing interactive systems - understanding, envisionment, design and evaluation but we have not really explored how to go about these processes. Part I also introduced
PACT, scenarios and personas, some useful constructs, and a useful framework for think­
ing about designing interactive systems. Part I has also covered the principles of design­
ing for accessibility and usability, and described a method for design based on scenarios.
Part II will provide techniques to enable designers to do all these things. If you want to
know about people, and to develop personas, you should know about how to interview
them, or get them to participate in design. If you want to evaluate some design ideas you
need to know how to sketch, prototype and evaluate. If you want to design good prod­
ucts, you need to understand methods for conceptual design and for physical design.
This part provides a thorough treatment of all of these.
Chapter 7 discusses methods for understanding the world of interactive systems design.
Many of these are also applicable to evaluation. Further techniques more closely asso­
ciated with evaluation are discussed in Chapter 10. A particular form of analysis that is
popular in interactive systems design is task analysis, which is covered in Chapter 11.
The more design-oriented methods, for envisioning physical designs and for exploring
the conceptual space of designs, are presented in Chapters 9 and 10. The background
for these, and the key issues of interface design are covered in Chapter 12, on the visual
aspects, and Chapter 13 on multimodal interaction.
The aim of this part is to be comprehensive in our coverage of the issues. There are many
proprietary methods that are provided by design companies and agencies, but they are
all based on the examples provided here. As we discuss briefly in Chapter 9, the form of
the construct, or modelling method, that designers use will affect which aspects of the
design stand out and which are played down. So the choice of method can be critical to
the insight provided. A task analysis, for example (Chapter 11), will focus on how easy it is
to undertake specific tasks, but will not say much about the overall navigational structure
of an interactive system. A focus group may provide useful ideas early on in a project, but
may not provide so much insight when designing the detail of a pop-up menu. Designers
need to understand the wide range of techniques that are applicable in interactive sys­
tems design and where and when they are best used.

Case studies
There are several interesting case studies that are used to illustrate the material in this
part. Chapter 8 uses the HIC case study and Companions to explore and illustrate many
of the issues. Chapter 9 returns to the MP3 scenario from the HIC project and presents a
detailed object-action analysis of the scenario, showing how such an analysis can lead to
an effective conceptual design. The same case is used to illustrate the development of a
design language and an interaction pattern. Chapter 10 uses the HIC to illustrate aspects
of evaluation. A detailed look at an edit function on a photo CD is also included.

Introduction to Part

Teaching and learning
This is not a part to be read completely in sequence. You should get to know the overall
structure by dipping into each chapter and reading the introduction, aim and summary.
Flip through the detail to get a high-level picture of the sort of things that are covered. If
you are doing an in-depth report on techniques for understanding, or evaluation, say perhaps to select appropriate methods for a particular project - then do read the appro­
priate chapter in detail and study the further reading and the Web links that go with the
Topics should be mixed in with an understanding of the overall design process provided
in Part I to give a feel for what is involved in design and how to do it. The list of topics
covered in this part is shown below, each of which could take 10-15 hours of study to
reach a good general level of understanding, or 3-5 hours for a basic appreciation of the
issues. Of course, each topic could be the subject of extensive and in-depth study.
Topic 2.1

Participative design

Section 7.2

Topic 2.2
Topic 2.3
Topic 2.4
Topic 2.5
Topic 2.6
Topic 2.7

Interviewing people
Developing questionnaires
Card sorting
Observation and ethnographic studies


Topic 2.8
Topic 2.9
Topic 2.10
Topic 2.11
Topic 2.12

Ideas development
Sketching and wireframes
Envisionment in practice
Conceptual design

Topic 2.13
Topic 2.14
Topic 2.15
Topic 2.16
Topic 2.17
Topic 2.18
Topic 2.19
Topic 2.20
Topic 2.21
Topic 2.22
Topic 2.23
Topic 2.24
Topic 2.25
Topic 2.26
Topic 2.27
Topic 2.28
Topic 2.29

Metaphors and blends
Design languages
Interaction patterns
Expert evaluation
Participative evaluation
Evaluation in practice
Task analysis
Graphical user interfaces (GUIs)
Interface design
Information design
Multimodal interaction
Mixed reality
Auditory interfaces
Tangible user interfaces
Gestural interaction
Surface computing


Sections 7.7, 8.1, 9.1-9.2
Section 8.2
Section 8.3
Section 8.4
Section 9.4
Section 9.3
Section 9.5
Section 9.5
Section 10.2
Section 10.3
Sections 10.1,10.4,10.5
Chapter 11
Section 12.3
Section 12.4
Section 12.5
Section 12.6
Sections 13.1-13.2
Section 13.2
Section 13.3
Section 13.4
Section 13.5
Section 13.5


Chapter 7
U nderstanding




Before creative design can start it is essential that the designer
develops a clear and thorough understanding of the people who will
be involved with the product or system, the activities that are the
focus of the design, the contexts in which those activities take place
and the implications for the design of technologies: 'PACT'. From this

requirem ents 139

7.2 Participative design 141
7.3 Interviews 142

7.4 Questionnaires 146
7.5 Probes 152
7.6 Card sorting techniques 153
7.7 W orking w ith groups 156
7.8 Fieldwork: observing activities
in situ 157

7.9 Artefact collection and 'desk
work' 161
Sum m ary and key points 163
Exercises 163
Further reading 164
Web links 164

Comments on challenges 165

understanding designers generate the requirements for the system that
is to be designed. However, it is rarely possible to acquire a thorough
understanding of requirements until some design work has been
completed. Requirements work (understanding), the design process,
representations of design (envisionment) and evaluation are tightly
The focus of the understanding process is on what people do, or might
want to do, and on any problems they are having with any system
currently in use. It is also about understanding how people do what
they do, so that designers can develop technologies that make aspects
of everyday life more efficient or more enjoyable.
In this chapter we present the main techniques for understanding
people's activities and encapsulating this for design. In software
engineering or information systems projects, this is a formal step which
is usually termed 'requirements analysis'. In interaction design it is
often referred to as 'research'.
After studying this chapter you should be able to:
• Understand what requirements are
• Understand the range of requirements generation techniques
• Use techniques for understanding people and their activities in
• Document the results as requirements on interactive technologies
and services.

Chapter 7 • Understanding

7.1 Understanding requirements
A requirement is ‘something the product must do or a quality that the product must have’
(Robertson and Robertson, 1999). Designers will study current activities and gather
stories of use and soon will have generated a great deal of information about the cur­
rent situation and about people’s goals and aspirations. The task now is to turn this into
requirements for a new product, system or service. Sometimes this is straightforward,
but often it will need a creative leap. This is why the analysis-design-evaluation process
is so iterative. The accuracy of the guess can only be judged when people review the
requirements, something that is best done with the aid of scenarios and early designs or
a prototype. Just to further complicate matters, additional requirements will emerge as
the design process continues.
There has always been much debate about which of the following terms should be
used for the requirements activity:
• Requirements gathering, which suggests requirements are lying around waiting to be
picked up with little interaction between designer and stakeholders
• Requirements generation, which suggests a more creative activity, that tends to deemphasize links to current practice
• Requirements elicitation, which suggests some interaction between stakeholders and
• Requirements engineering - often used in software engineering projects, usually a
very formal approach.
This is one of the reasons we have moved to the term ‘understanding’, as it encapsulates
ideas of gathering and generation. Many interaction design projects start from a ‘design
brief which may be quite a vague description of something they want. Often clients will
require a requirements specification - a formal written document that contains the require­
ments. Developers also need a clear requirements specification at some point in the devel­
opment process so that they can cost the project and manage it successfully. Requirements

Requirements templates
The use of a standard format, or template, for specifying requirements is useful, particu­
larly in larger projects. The exact presentation of the information is not important, but
at a minimum it should include for each requirement:
• A unique reference number, ideally also coding whether the requirement is func­
tional or non-functional
• A one-sentence summary
• The source(s) of the requirement
• The rationale for it.
As Robertson and Robertson (1999) suggest, there are additional elements which
will greatly add to the value of the requirements specification. The most significant of
these are:

The criteria for measuring whether the requirement has been satisfied
A grade for the importance of the requirement, e.g. on a scale of 1-5
Dependencies and conflicts with other requirements
Change history.




Part II • Techniques for designing interactive systems

specifications increasingly include prototypes, screenshots and other media. When writ­
ten they should be expressed in clear, unambiguous language, and worded so that it will
be possible to test whether the requirement has been met in the final system.
Conventionally, requirements are divided into two types, functional and non-func­
tional. Functional requirements are what the system must do. Non-functional require­
ments are a quality that the system must have. These qualities may be crucial factors
in the acceptability, sales or usage of a product. Non-functional requirements cover a
number of aspects of design, including image and aesthetics, usability, performance,
maintainability, security, cultural acceptability and legal restrictions. Also important
are the data, or media requirements of any system - the type of content that it has to
deal with and the various media that will be used.
For both types of requirements, note that how the technology will meet the require­
ment is not specified. This is a later part of the design activity. It is best to supplement
the list of requirements with some supporting evidence - interview or observation
reports, photographs of artefacts, video snippets if practicable. This helps readers of the
requirements specification to understand the reason behind items in the list.

Prioritizing requirements
Requirements should be reviewed with customers and clients and modified as neces­
sary. Decisions will almost always be made about the relative priority of the require­
ments, since few design projects have unlimited resources. One way of doing this is by
using the ‘MoSCoW rules’. These classify requirements into:
• Must have - fundamental requirements without which the system will be unwork­
able and useless, effectively the minimum usable subset
• Should have - would be essential if more time were available, but the system will be
useful and usable without them
• Could have - of lesser importance, therefore can more easily be left out of the current
• Want to have but Won’t have this time round - can wait till a later development.
The MoSCoW method is part of the Atern development method (see Box 3.2 on agile
development). The method takes a very business-focused view of prioritizing require­
ments, tying in the specification of priorities with the overall business costs of develop­
ing a system.

Challenge 7.1
The Home Information Centre (HIC, the focus of the case study in Chapter 6) aims to be
a new device for the home. Which of these requirements on the HIC are functional and
which non-functional? Discuss issues of prioritizing the requirements.

Unobtrusive in the home environment
Option to print out details
Fast download of information
Direct 'panic' link to the emergency services
Volume control/mute features
Customizable to support choice of languages, including those with different character
7 Provides e-mail
8 Security for each individual user.

Chapter 7 • Understanding


Participative design

Research work involves using a variety of techniques to understand and analyse some­
one else’s needs, goals and aspirations. The key thing for designers to remember is that
they are not the people who will be using the final system. Designers need to understand
the requirements of other people. This is not easy, but talking to people using interviews,
observing people and recording their activities on video, organizing focus groups, work­
shops, etc. will all help the designer to understand both the requirements for the new
design and the problems people are having with existing ways of doing things. By engag­
ing with people using various techniques that encourage the participation of people in
the design process, designers will acquire a large number of stories that form the basis
for the analysis work. Recasting several similar stories into more structured conceptual
scenarios will also help the designer to understand and generate requirements.
Throughout this book we emphasize the need to take a human-centred approach to
design. First, it is important that human characteristics and activities are taken into
account. But beyond this, wherever possible, it is right that the people who will use new
interactive technologies have an input to the design process itself. We include the qualifi­
cation ‘wherever possible’ not because we think that it is ever proper to exclude the inter­
ests of the widest range of stakeholders from the design process, but because in large-scale
commercial products it is feasible to involve only a tiny proportion of those who will use
the eventual system. The situation is very different from the development of custom-made
systems for a small group of people, where it is genuinely feasible for the people con­
cerned to act as co-designers and so acquire ownership of the technology to be introduced.

The socio-technical tradition
This design philosophy of involving people in the design of their systems is usually
attributed to the Scandinavian tradition of worker participation in the management of
the workplace. There are also links to the British socio-technical design movement and
to the social informatics movement in the US (Davenport, 2008). This started with an
emphasis on human considerations in the design of systems to support manual work,
such as coal mining, but later evolved methods for user involvement in the design of
computer-based systems. The work of Enid Mumford at Manchester, and Ken Eason,
Leela Damodoran, Susan Harker and their colleagues at Loughborough University and
elsewhere, is central to this development of the socio-technical approach. Methods
embodying the socio-technical philosophy included Mumford's ETHICS (Mumford,
1983, 1993), the HUFIT toolkit (Taylor, 1990), which provided a comprehensive, prac­
tical set of techniques for working with users, and ORDIT (Eason et al., 1996), which
aimed to incorporate organizational considerations into systems design.
The Scandinavian participatory design movement of the early 1980s was also impor­
tant. This was very much a politically informed initiative, with the emphasis on workplace
democracy and empowering workers as co-designers of work practice and the tools
supporting it. Techniques such as paper prototyping were invented so that workers were
not disadvantaged in working with technologists. The most influential of such initiatives
was the work of Pelle Ehn and colleagues in the UTOPIA project (Bodker et al., 1987;
Ehn and Kyng, 1987). More recently, Pekkola et al. (2006) have reviewed these earlier
approaches and suggested how the demands of information systems development and
participative design can be brought together. Their method uses an iterative approach to
design, bringing in participative methods and prototyping in order to ensure stakeholder




Part II • Techniques for designing interactive systems

involvement throughout the process. Stakeholders were able to evaluate prototypes as
a normal part of their work. Deborah Mayhew's Usability Engineering is another well
documented and structured human-centred approach (Mayhew, 2007) as is the rapid
contextual design of Karen Holtzblatt (Holtzblatt, 2007).

Challenge 7.2
Incorporating input from those who will be affected by a changed system into the
requirements process helps to ensure that the eventual technologies have a good fit with
the people, activities and contexts they are designed to support. There is also a strong
ethical argument for user involvement. Can you think of another reason for doing this?

Acting out requirements
Alan Newell and his colleagues (e.g. Newell et al., 2007) have developed methods for
acting out requirements in order to make them more understandable to the groups
of people they are designing for - primarily older people. The technique requires the
designers to work with a professional script writer to develop a short stage play based
on the requirements that have been generated. This is acted out by trained actors with
the stakeholders making up the audience. Following the play a trained facilitator leads
an audience discussion on the play and the issues that it raised. These discussion feed
back into the understanding process, helping to provide a rich understanding of the
hopes, fears and concerns of the people.



One of the most effective ways of finding out what people want and what problems they
have at the moment is to talk to them! Interviews with all the various stakeholders in
the domain are a vital way of gathering stories. Designers employ a range of different
styles of interview. The structured interview uses questions that are developed before­
hand. The interview follows the wording exactly. Public opinion polls, for example of
the sort produced in great numbers before elections, are normally based on structured
interviews. Structured interviews are reasonably easy to carry out, simply because of
the degree of pre-structuring. However, people are limited to very restricted replies, and
it is difficult for the interviewer to follow up the unexpected response. Here is an extract
from a structured interview pro forma about a student information system.
Thinking about the Department's website, about how often would you say that you have
used the following during the last week:

not at all □

most days □

every day □

more than once a day □

Staff home

not at all □

most days □

every day □

more than once a day □


not at all □

most days □

every day □

more than once a day □

Chapter 7


Designers very frequently use semi-structured interviews. Sometimes, the interviewer
is armed with pre-prepared questions, but can reword these as appropriate and explore
new topics as they arise. Often, the interviewer simply prepares a checklist, sometimes
with suitable prompts such as ‘Tell me about the first things you do when you get into
the office in the morning’. Clearly, this free-form approach is more demanding for the
interviewer, but the data obtained does generally repay the effort.
An example of such an interview is shown in Figure 7.1, with some annotations
about interviewing technique. The interview is designed to start at a high level, then to
probe at a greater level of detail. The analyst’s checklist of topics to cover for this exam­
ple included the type of information needed, current sources (paper or on-line), and
specific examples of information needs.
Completely unstructured interviews are sometimes used where it is particularly
important to minimize designers’ preconceptions, or where very little background
information is available beforehand. As the term suggests, there are no preset questions
or topics beyond the general subject of the project in question.

Contextual inquiry
Contextual Inquiry (Cl) is a first-stage design method by Holtzblatt and Beyer (Beyer
and Holtzblatt, 1998; Holtzblatt, 2012). They observe, 'The core premise of Cl is very
simple: go where the customer works, observe the customer as he or she works, and
talk to the customer about the work. Do that, and you can't help but gain a better
understanding of your customer.'
Cl brings together a number of techniques including artefact collection and obser­
vation under one unifying theme or philosophy.
There are four guiding principles of Contextual Inquiry:
1 Context. Here the advice is to go to the customer's workplace and observe how work
is actually carried out. This allows the analyst to experience the rich everyday detail
of work. It is best to focus on concrete data and tasks (i.e. user stories) rather than
generalized abstraction.
2 Partnership. One of the core premises of Cl - and of its Scandinavian ancestors - is
that analyst and customer are expert in their different fields. The analyst should be
looking for patterns and structure in the work while the customer contributes her
knowledge of how the work really gets done. As redesign ideas occur, they can also
be discussed. Thus customers can genuinely influence the analyst's interpretations of
the work and design ideas based upon it. The relationship is characterized by Beyer
and Holtzblatt as the 'master-apprentice model'.
3 Interpretation. It is not enough simply to observe and document: the analyst must
interpret workplace data so that it is properly understood. The analyst abstracts from
the stories, producing a more conceptual interpretation. The analyst should reflect
her interpretations back to the customer and listen to the response. Be prepared to
be wrong.
4 Focus. Each site visit and interview needs a focus, though concentrating on one part
of the work helps to see detail, but at the expense of other aspects. Be clear about
the focus and try to make neither too broad nor too narrow.

................- -------- --- --.......-.....................-..-..-............................... J

Challenge 7.3
What sort of information is likely to be missed by interviews? Why?

& }



Part II • Techniques for designing interactive systems

Stories, scenarios and early prototyping in interviewing
«- Stories and scenarios
have already been introduced
in Chapter 3

Scenarios and stories are helpful aids to understanding activities and help avoid having
people imagine (or reconstruct) situations in the abstract. For example, people can be
askec] t0 recall a typical ‘day in the life’ or incidents when the current technology does
not support what they need to do. This will identify circumstances that the new design
must take into account.
Once there is a rough idea of what the new technology might do, discussing a sce­
nario will highlight many issues, from the naming of individual functions to the impact
of changes in work practice. Prototypes - anything from paper sketches to semi­
functioning products - are very often used to embody scenarios in possible technology.
For example, in the later stages of analysis for a shared notebook for engineers, we used
simple prototypes created in PowerPoint coupled with small usage scenarios. These
were projected on a screen and discussed in a small group meeting, prompting discus­
sion about the match between our design ideas and the way the engineers currently
disseminated information.
Whether or not a prototype is used, the analyst and the customer ‘walk through’ the
scenario, while the analyst probes for comments, problems, possible alternatives and
suggestions in general. Depending on the outcome of the scenario/prototype walk­
through, modifications and further iterations may be desirable. Where many new issues
emerge, it may be the case that the early concepts underlying the scenario or prototype
are misconceived, and should be radically rethought.

Chapter 7

Think-aloud commentaries
When it is necessary to know a good deal of low-level detail about current technology,
users can be asked to talk through the operations concerned - including their internal
cognitive processes - as they use the technology in question. This data, properly termed
a Verbal protocol’ (Ericsson and Simon, 1985), can provide helpful indications of cur­
rent problems. It is important to remember, however, that by imposing the requirement
to generate a commentary you are interfering with the very process you are attempting
to study. Further, not all cognitive processes can be accessed by the conscious mind. The
description of the ‘contextual interview’ in Beyer and Holtzblatt (1998) suggests some
ways of alleviating this problem.

Practical considerations in interviewing
This section contains some practical ‘hints and tips’ from our experience of interviewing
in a variety of analysis situations.

Get to know the background. ‘Idiot questions’ can uncover unspoken assumptions,
but use them deliberately, not by accident. Be careful about using people’s own jargon
until you are sure that you have it right. For work activities, background research might
include studying company reports, brochures, websites and organization charts or scan­
ning through software manuals and promotional materials. For home and leisure activi­
ties, what is relevant depends very largely on the context.
Keeping track of the interview

Interviewing is hard work and more effective if carried out by a pair of interviewers. One
person can take the lead while the other makes notes. Of course, the note-taking burden
is relieved if the interview is audio- or video-recorded. In this case, make sure you check
the equipment before each session and periodically during the interview. Even when
the interview is recorded, notes are still useful, especially if they include regular records
of the time, which will help to find key points - it will take you one hour at the least to
watch one hour of videotape even without any analysis or transcription. In addition,
your notes will be vital if (for example) building work outside has muffled a section
of the audio, or the heavy regional accent that was understandable face-to-face proves
impenetrable on tape. A full transcription is rarely needed, but if it is, an audio-typist
can save hours of your time. The typist will need briefing about any technical terms.
Telling stories

Just because telling stories and listening to them is such a natural thing to do, they
can be misleading. As listeners, designers are looking for current problems, scope
for improvements or endorsements of early design ideas. As storytellers, people may
respond by giving such things disproportionate emphasis. You need to be aware of this
in analysing interview data.
Reflection and exploration

Reflecting back during the interview helps confirm that you have understood what has
been said. It is often a good idea to have the interviewee review a summary of the inter­
view. This might be because the interviewee’s knowledge is central to the new design,




Part II

Techniques for designing interactive systems

sensitive material is involved or the context is very unfamiliar. You should also look over
the notes of the interview yourself to identify any points that need clarification.
General-purpose exploratory questions

These help the interview along, especially in the early stages or with a taciturn inter­
viewee. Some we have found useful are:
‘Tell me about your typical day.’
Tell me three good things ab o u t. . . ’
‘and three bad things.’
‘What if you had three wishes to make the application better?’
‘What has gone wrong with the application recently? How did you cope?’
‘What else should we have asked about?’
When to stop

Deciding when to stop interviewing means balancing practical constraints against the
comprehensiveness of the data. Certainly, all significant stakeholder groups must be
covered. In the case of generic product development, Beyer and Holtzblatt (1998) sug­
gest two or three interviewees per role (or type of stakeholder) across three or four
different types of organization. In many cases, client resources limit the process. With
unlimited resources, the general rule is to stop once no new insights are being obtained.



Most of the methods we discuss in this chapter involve working with people face-toface. However, there are ways of obtaining requirements information at a distance. The
most common of these is the questionnaire, but there are more ingenious, novel tech­
niques as well.
Questionnaires are one way of streamlining the understanding process if a large num­
ber of people are to be surveyed and resources are not available to interview them indi­
vidually. However, constructing a workable questionnaire is surprisingly difficult and
time-consuming. It is a skilled task to devise the wording of questions when there are no
opportunities to detect and clear up misunderstandings as they happen. Questionnaires
need to be designed, prototyped and evaluated in the same way as any other form of
interaction design. For small numbers of people - up to 10 or so - an interview will
obtain the same information, and more, in a manageable way. This will consume little or
no extra resource if the time required to construct a questionnaire is taken into account.

Challenge 7.4
Consider the following items from a questionnaire about use of the Internet. Are there
any problems with the wording? How could the items be improved?
(a) How often do you access the Internet? (tick one)
Every day □
Most days □
About once a week □

Chapter 7 • Understanding

A b o u t o n c e a m o n th


Less th an o n c e a m o n th


P lease list all ty p e s o f m a teria l w h ic h y o u a c c e s s fre q u e n tly u sing th e In tern et.

Questionnaires are ideally suited to gathering a large amount of quantifiable data, or
to capture responses from people who cannot be involved more directly. With the pro­
liferation of on-line questionnaire services such as Survey Monkey (Figure 7.2), quite
complex questionnaires can be constructed and made available on the Web. Another
technique for gathering data is ‘crowd sourcing’. Here, small specific tasks are put on the
Web and volunteers sign up to take the tasks in return for a small payment. Amazon’s
‘Mechanical Turk’ is the best-known example, but needs careful design of the task if it is
to be effective.
A good questionnaire is time-consuming to construct so that all the items:

are understandable
are unambiguous
collect data which actually answers evaluation questions
can be analysed easily.

Response rates to questionnaires can be very low indeed - return rates of under 10 per
cent are common if the intended respondents have no particular stake in the design of
the technology or incentive (being entered into a prize draw, for example) to partici­
pate. Where questionnaires are administered as part of a face-to-face evaluation session
most people will complete them, but people who take them away to finish in their own
time, or who do the questionnaire on the Web, very often don’t.

Figure 7.2 Screenshot of see



Part II • Techniques for designing interactive systems

Finally, analysing the data requires thought and time. If most respondents have
awarded feature A 5 out of 7 for usefulness but feature ‘B’ 6 out of 7, does this really
mean that feature B is better? Or is it enough that both features score above the mid­
point? Maybe feature A was misunderstood - without a follow-up question the data is
difficult to interpret. This is easy to do in an interview, but would add significantly to
the length of a questionnaire. Where respondents have been given the opportunity to
express opinions as unstructured answers, you will need to devise a scheme for classify­
ing this material so that it is usable.
Perceptions of system design are often collected through rating scales, known as
Likert scales (Likert, 1932). The Likert scale is the most common of a number of meth­
ods for eliciting opinion. People are asked to indicate their agreement with a statement
using a five-point scale:
Strongly agree
Strongly disagree
or a seven-point, four-point or ten-point scale. The scale is attached to each of a number
of statements such as:
I a lw a ys k n e w w h a t I sh o u ld d o next. (T ic k o n e b o x )

1 Strongly agree □
2 Agree □
3 Neutral □
4 Disagree □


Stro ng ly d isa g re e □

Ico n s w e r e e a sily u n d e rsta n d a b le .

1 Strongly agree □

2 Agree □
3 Neutral □
4 D isa g ree J

S tro n g ly d isa g re e □

The destination of links was clear.
1 Strongly agree □

2 Agree □
3 Neutral □

D isa g re e □


Stro ng ly d isa g ree □

Getting the wording right and choosing appropriate statements to elicit information
relevant to the enquiry is surprisingly difficult and much trial and revision of statements
will be required. The items on a questionnaire should be as specific as possible. A probe
statement such as ‘The system was easy to use’ does provide a general impression but
gives very little information for redesign if you do not supplement it.
Another approach is to devise ‘bipolar’ rating scales, often called semantic differen­
tials. These derive from the work of Osgood (Osgood et a i, 1957) and have evolved into
a very powerful way of uncovering the feelings people have towards ideas, products
and brands. For example, Brian Lawson (2001) used semantic differential to find out

Chapter 7

what people liked about pubs and we have used similar methods to explore what peo­
ple liked about places and how they were represented in a virtual environment (VE).
The ‘place probe’ (Benyon et al, 2006) was designed to obtain people’s responses to a
photo-realistic VE, of different places. Deriving from the work of Relph and others about
the sense of place (Relph, 1976), the probe contained semantic differentials about the
quality of the images, the sense of freedom people had to move around and their over­
all visual perception and subjective feelings of the place. Figure 7.3 is an example of a
semantic differential. Web-based questionnaire services will often give clear and good
advice on types of question and how to design questionnaires.

K e y fe a t u r e s o f th e p la c e

On the tables provided in each question below, please mark a cross in the box that
best describes your experience in relation to the adjectives provided at either side.
Below is an example fo r an experience that was 'quite bad' and 'very light'.
Exam p le
V e ry

Q u ite

N e it h e r


Q u ite

V e ry





Did th e im a g e s th a t w e r e d isp la y ed se e m ?
V e ry

Q u ite

N e it h e r

Q u ite

V ery









Did th e m o vem e n t o f th e im ag es se e m ?
V ery

Q u ite

N e it h e r

Q u ite

V e ry









Did y o u feel th a t y o u w e r e ?
V e ry

Q u ite

N e it h e r

Q u ite

V e ry











Figure 7.3 Semantic differential



Part II • Techniques for designing interactive systems

Did you feel that the environm ent w as?
V ery

Q u ite

N e ith e r

Q u ite

V e ry





















Did you feel that the environm ent w as?
V e ry

F ig u r e

Q u ite

N e ith e r

Q u ite

V e ry





















7.3 Continued

To gather requirements and opinions about system features several ready-made
and validated usability questionnaires are available, for example QUIS (Questionnaire
for User Interface Satisfaction) from the University of Maryland and SUMI (Software
Usability Measurement Inventory) from the University of Cork. These are ‘industrial
strength’ instruments and there is normally a fee for their use. Others may be found
in textbooks and on the Web, but in the latter case be sure that their source is a reli­
able one.
The ‘hints and tips’ in Box 7.2 (an edited version of Robson, 1993, pp. 247-52)
should help you to produce more worthwhile questionnaires. If the questionnaire is very
lengthy, however, or targeted at a very large group, then we strongly recommend you
consult a reference such as Oppenheim (2000) or an expert in questionnaire design.
Perhaps the most important piece of advice is to pilot the questionnaire in draft form
with a few people who are similar to the target group. It is always surprising how an
apparently simple question can be misunderstood.

Chapter 7 • Understanding

Hints and tips for design of questionnaires
S p e c if ic q u e s t io n s a r e b e t te r th a n g e n e r a l o n e s

General questions (a) tend to produce a wider variety of interpretation by respondents;
(b) are more likely to be influenced by other questions; and (c) are poorer predictors of
actual behaviour.
General: List the software packages you have used.
Specific: Which of these software packages have you used?
Visual Basic □

Word □

Excel □

PowerPoint □

C lo s e d q u e s t io n s a r e u s u a lly p r e f e r a b le to o p e n q u e s tio n s

Closed questions help to avoid differences in interpretation. Open questions are more
difficult to analyse, but can be useful, for instance, when seeking comments in the
respondent's own words, when not enough is known to construct closed questions, and
for potentially sensitive items.
Open: People look for different things in a job; what sort of things are important to
you in your job?
Closed: People look for different things in a job; which one of the following five
things is most important to you?
Good pay
A feeling of achievement
Ability to make your own decisions
Good people to work with
Job security


C o n s id e r a 'n o - o p in io n ' o p tio n

If there is no such option people may manufacture an opinion for the questionnaire.
Mobile communications technology has made life easier. Do you agree, disagree or
not have an opinion?
Agree □

Disagree □

No opinion □

However, a middle choice may encourage a non-committal response. One strategy is
to omit the middle choice and follow up with an 'intensity item' which separates out
strong from mild feelings.
Do you think mobile communications technology has made life easier or more dif­
ficult? Please tick the number which reflects your opinion.





More difficult

How strongly do you feel about this?
Extremely strongly






Not at all strongly

V a ry t h e o r ie n t a tio n o f ra tin g s c a le s o r in t e r s p e r s e w ith o t h e r q u e s tio n s

If a questionnaire contains a lot of similar scales, all of which have, say, the 'good' end at the
left and the 'bad' end at the right, people may go down the page ticking each scale in the
same place. Either reverse some scales or put some other types of question in between.
A p p e a r a n c e , o r d e r a n d in s tr u c t io n s a r e v ita l

The questionnaire should look easy to fill in, with plenty of space for questions and
answers. Initial questions should be easy and interesting. Middle questions cover the
more difficult areas. Make the last questions interesting to encourage completion




Part II • Techniques for designing interactive systems

and return of the questionnaire. Keep the design simple and give clear instructions,
repeating them if confusion seems possible. Ticking boxes is less confusing than circling
A d d in tr o d u c t o r y a n d c o n c lu d in g n o te s

The introduction should explain the purpose of the survey, assure confidentiality and
encourage reply. The concluding note can ask respondents to check they have answered
all questions, encourage an early return of the questionnaire with the deadline date
(and return details, if not using a pre-addressed envelope), offer to send a summary of
the findings, if appropriate, and thank them for their help.
M a k e r e tu r n e a s y

Using internal mail is often easiest (include a pre-addressed envelope). Or arrange
for a box to be placed in a convenient place to be collected by you. For people who
habitually use e-mail, an e-mail questionnaire can be one of the easiest ways to get a
good response rate. The Web is also worth considering. Postal returns should of course
include a pre-paid return envelope.



Probes are collections of artefacts designed to elicit requirements, ideas or opinions in
specific contexts. ‘Cultural probes’ were developed by Bill Gaver and colleagues (Gaver
et al., 1999) in working with elderly people located in three European cities. The overall
aim was to design technologies that would foster greater participation in the community
by older people. The designers first got to know the groups in person, then introduced
them to the cultural probes packages. Each person received a collection of maps, post­
cards, a disposable camera and booklets - each item being carefully designed to stimu­
late interest and curiosity, and suggesting ways in which people could use it to send
£ ideas back to the designers. They were ‘designed to provoke inspirational responses’
(ibid., p. 22). Postcards such as that shown in Figure 7.4, for example, asked people
to list their favourite devices. The disposable cameras had customized covers which
suggested scenes to be captured, such as ‘the first person you will see today or ‘some­
thing boring’. Over a period of weeks, many of the probe materials were sent back to the
designers, carrying rich data about the lives of the elderly people. Not all items worked
out as planned - the authors do not specify which - and the materials were selectively
redesigned before being distributed to subsequent participants. All in all, the exercise
was highly successful in capturing the general sense of what it meant to be elderly in the
communities involved, although it is noted that the results did not have a direct impact
on design.
The philosophy behind cultural probes was rather different than trying to gather
requirements and illustrates well the difference between requirements elicitation and
requirements generation. Gaver argues that probes are meant to confront, they are
intended to provide inspiration for designers rather than elicit specific requirements.
Technology probes are another form of probe that were used to gather requirements
for home technologies and the area has now evolved into a whole area of ‘probology.
In discussing the use of mobile probes (Hulkko et al., 2004) it is argued that probes

Chapter 7



Wat is uw favoriete


Kensington Core
L o n d o n SW7 2EU


U .K .



Figure 7.4 Postcard
used as a 'cultural
(Source: Gaver, W.W., Dunne, T.
and Pacenti, E. (1999)
Design: Cultural probes,
Interactions, 6(1), pp. 21-29
© 1999 ACM, Inc. Reprinted
by permission, http://doi.acm.

are humane, they create fragments of understanding and insight and use uncertainty
through providing stories. Probes inspire and provoke designers to engage with the lives
of others. Another analysis of probes (cultural, mobile, domestic, urban) by Graham
et al. (2007) concludes that probes represent the ‘turn to the personal’ in a direct refer­
ence to the ‘turn to the social’ that happened in HCI at the beginning of the 1990s (see
Chapter 18 for more on this). Probes are an amalgam of social science methods (such
as photography, diaries, life documents, etc.) that enable designers to focus upon the
individual’s everyday life, going beyond the general.


Card sorting techniques

Card sorting refers to a number of techniques concerned with understanding how peo­
ple classify and categorize things. It has been said that trying to find things on a website
is like looking for the scissors in someone else’s kitchen. You know there are some, but
finding them can be another matter altogether. How people organize things is a very
personal matter. Card sorting is particularly relevant in website design as the structure
of the content is critical.
As a method of understanding, card sorting can be used in a number of ways. At its
most basic card sorting involves writing concepts onto cards and then grouping them
in different ways. A group of people work with a facilitator to structure data, concepts,
objects or other artefacts, trying to understand what categories are most appropriate to
group them together. This results in a taxonomy (a classification) and a set of high-level
concepts known as an ontology.

Inform ation arch itecture
is the study o f h o w to design
digital structures and w e
return to this in Ch ap ter 14.

Part II • Techniques for designing interactive systems

Where the results from a large number of people are available, various mathematical
grouping techniques can be used. Card sorting can be conducted face to face or using
an on-line tool. Hudson (2012) gives the example of a supermarket checkout vegetable
pricing machine (Figure 7.5). If a customer has bought some onions, which category
should they select? How about if they have some courgettes, broccoli, aubergines? If
customers have to spend a long time searching for the right category (and any casual
observation of supermarket checkouts suggests they do) queues will build up, people
will get dissatisfied and go elsewhere next time they want to shop.

Figure 7.5 Supermarket vegetable weighing machine
(Source: Henglein and Streets/cultura/Corbis)

As a method of understanding, card sorting can be a very effective method of gaining
insight into how people think about things and classify them. There are two types of card
1 An open card sort starts with blank cards and participants are asked to write down
the objects or actions they think are important in some domain. These are then gath­
ered together into categories
2 A closed card sort starts with predefined categories and asks participants to place
objects into the categories.
As with most methods for understanding it is likely that the analyst will move between
these different types depending on the questions being addressed. In the question
of understanding what problems people are having using the checkout display, you
would use a closed card sort because you already have the categories (the pictures on
the display). If you are trying to understand what categories different people would
choose for vegetables, give them a list of vegetables and ask them how they would
like to group them. Hudson did this with 26 participants and got the results shown in
Figure 7.6.
You can also look at all the pairs of items that different people put in the same cat­
egory, and once again look for agreement or disagreement across different people.
Different classifications may suggest that there are distinct types of user who may
need different classifications. A cluster analysis such as this can be used to produce a

Chapter 7 • Understanding

Kiwi Fruit
Swede / Rutabaga
Squash / Marrows
Courgettes / Zucchini
Broccoli / Calabrese

. .Mushrooms___
G a r lic __________________
Fennel (bulb)

Figure 7.6 Results of card sorting exercise
(Source: chart 26 participants.jpg)

Figure 7.7 Dendogram
(Source: http://dienekes.

dendrogram (Figure 7.7) which shows the hierarchical clustering of objects (or actions).
Representations such as these can then be used in a reverse card sorting (or tree sort­
ing) method to see how the hierarchy is traversed for different tasks.
Analysts really need to practise card sorting to understand the type of insight it can
provide and when best to use the technique. A hard part of this is knowing what to sort,
which objects or actions to include and when in the overall understanding process the
technique will be most helpful.



Part II • Techniques tor designing interactive systems


Semantic understanding
The dendrogram representation in Figure 7.7 is also used in the repertory grid tech­
nique (RepGrid), which is based on the work of psychologist George Kelly (Kelly, 1955). In
this method participants are asked to describe the concepts that they think characterize
some topic. For example you might be investigating the qualities of personal devices and
ask people to give adjectives (the constructs) that describe what they like about their
mobile phone and other personal items (the elements). These descriptive qualities are
then used to provide ratings of the constructs. For example a mobile phone could be
rated as heavy versus light, slim versus fat, comfortable versus uncomfortable and so on.
This type of analysis is also related to the semantic differential (Section 7.4) and to
other techniques that focus on the measurement of meaning (Osgood et al., 1957).


Working with groups

An alternative to asking individuals or stimulating individuals to provide information
is to work with groups of people. The most common example of this is the focus group.
Here a group of people are posed questions by facilitators and encouraged to react to each
other’s comments. If they are part of a group, people can be asked to describe how they
cooperate to manage activities. Members of the group can stimulate each other’s memo­
ries, and discussion may flow more naturally than in the single-person interview. The
approach is widely used - the early stages of the Joint Application Development (JAD)
method (Wood and Silver, 1995), for example, employ a type of focus group comprising
customers and developers in defining the scope and requirements for a new system.
Focus groups can be enhanced by the use of scenarios, prototypes and other stimuli.
For example, we have used a robotic pet as a stimulus for talking about companion­
ship with groups of older people, printed scenarios and screenshots of a mock-up auto­
matic teller machine (ATM) to generate requirements for personalized ATM services,
and maps and visitor guides to generate requirements for a mobile guide application.
However, group discussion may also inhibit comment about sensitive issues, and can
have the effect of highlighting unusual incidents disproportionately.
Many techniques have been developed to support focus groups. One such example is
CARD (Collaborative Analysis of Requirements and Design, Tudor et al, 1993; Muller,
2001). Used by Microsoft and Lotus among others, CARD uses physical playing cards
with which a group can lay out, modify and discuss the flow of an activity. In the analy­
sis phase, each pre-formatted card contains people’s accounts of what is done and why
for an individual component of the activity. Requirements on innovations in human
practices or technologies can then be discussed around the cards. CARD is also intended
to support design and evaluation.

IDEO Method cards
This is a collection of 51 cards representing different ways that design teams can under­
stand the people they are designing for. The cards can be used by researchers, designers,
engineers and mixed groups to think about design issues and generate debate. The cards
are classified as four suits - Ask, Watch, Learn, Try - that describe various types of activity.



------------------------------------ — --------------------------------------------------- -—

............... ................

Chapter 7 • Understanding


Another important group activity is brainstorming. Once again there is a wealth of good
advice from management consultants and system designers about how to organize and
structure brainstorming sessions. Brainstorming sessions should be fun to participate
in, but to achieve this they require an experienced facilitator. They also require some
stimuli, whether as pictures, text or video, to get the ideas flowing. Participants will
need some way of recording their thoughts and ideas; a whiteboard, flip chart, paper
and coloured pens. Post-it notes in different colours can be used to capture ideas. This
can be useful if the brainstorming session is followed by an affinity analysis where ideas
are grouped together using different criteria.
An important point about brainstorming is not to dismiss ideas too soon. The ses­
sions should begin with an ‘anything goes’ approach. Generate plenty of ideas. These
can then be filtered in a part of the session that tries to look at the feasibility of the ideas
and their practical impact. A good technique for helping brainstorming sessions is to get
different members of the group to adopt different roles - the ideas generator, the critic,
the sceptic, the pragmatic, the documenter, and so on.







.1 . . . I I 1

111 U J U l l I U i

........................... -

Fieldwork: observing activities


......................................................................................................... ..............—


Observing people’s activities as they happen is another excellent, though time­
consuming, method of understanding and requirements generation. Interviews and
questionnaires provide one side of the story, but it is difficult for people to describe all
the details of the relevant aspect of everyday life or work. Sometimes this is because the
activity is intrinsically difficult to describe in words - many manual procedures fall into
this category - or because it requires complex and subtle cooperation with other people
or events. In other cases, an interviewee may describe the ‘official’ procedure rather than
how something is actually done in practice. They might be embarrassed to admit to some
difficulty they are having, or may just tell the designer something to get rid of them.
Data from observation helps to get round these problems. In its simplest form, the
designer can simply ask ‘Can you show me how you do that?’ during an interview. More
complex or larger activities will require someone to spend some time on site observing
as unobtrusively as possible. This is best done after some initial interviewing, so you
have some idea what it is you are looking at. Everyone at the scene must be informed
of what is happening and grant their permission in advance, even though they may not
be your main focus. Ideally you need to see a range of variations on the normal activ­
ity and situations where things go wrong, but this may not be possible in many situa­
tions. Here the important point is to identify what you have not observed, so you do
not over-generalize from your data. If you are lucky enough to be able to choose what
you observe, then, just as with interviews, the time to stop is when no new information
appears. As in interviews, notes should be taken and video recording is very useful, par­
ticularly for sharing the observation with other design team members.
Of course, observation is not without its difficulties. Being unobtrusive is a skill of its
own, and your very presence will naturally tend to make people self-conscious and may
alter their behaviour. With time, this effect will decrease. It is much less of a problem
where the activity you are observing absorbs all the participants’ attention, or if you can
find a task to carry out which does not interfere with your data collection. It is also hard to
observe effectively where the activity is simply one of people processing data at computers
with little or no interaction with other people or artefacts. Here it would be more produc­
tive to ask people to demonstrate aspects of interest rather than waiting for them to occur

♦“ The future workshop
(Jungk and Mullert, 1987)
is a brainstorming technique
(see Chapter 6)


Part II • Techniques for designing interactive systems

in real time. There are also ethical issues associated with observing people, permissions
need to be obtained and anonymity of who said and did what should be ensured.

Challenge 7.5
Practise your observational skills next time you are working in a small group on a joint
task, obtaining the agreement of the rest of the group first. Ideally, the task should involve
working with papers, on-line material or some other tangible artefacts. Imagine that you
are designing new technology to improve group working. Note how the group interact
with each other and the artefacts. Review your notes afterwards from the point of view of
identifying requirements on the new design.






- .................... - ...............................................................

Workplace studies

C h ap ter

16 discusses

co llab orative w o rk

Workplace studies have become the most widely practised requirements method in the
area of Computer Supported Cooperative Working (CSCW). By studying work as it actu­
ally happens in its real-world setting, researchers and practitioners aim to overcome
many of the difficulties inherent in CSCW. Another factor in their popularity has been
the high proportion of CSCW researchers who come with backgrounds in sociology and
anthropology, where ethnography - the key approach in workplace studies - has long
t>een Practised. (Strictly speaking, an ‘ethnography’ is the output of observational fieldwork rather than the fieldwork itself.)
In the early twentieth century, pioneering ethnographic anthropologists endeavoured
to understand an unfamiliar way of life through what has become known as ‘participant
observation’ - learning about language, activities and culture through spending months
or years living in the community under study. The anthropologists talked to people,
observed day-to-day life in detail, and collected not just physical artefacts but stories,
myths and so on. Eventually, the resulting personal experience and field data were ana­
lysed and recorded as an ethnography. Sociologists, notably those from the University of
Chicago in the 1930s, employed similar techniques in the study of societies and groups
closer to home. In both domains, the basic approach continues to be used, including the
core principle that the ethnographer should not interpose his or her own theoretical or cul­
tural frameworks or expectations between the field data and the resulting ethnography.

Ethnomethodology and other theoretical difficulties

Following the work of Suchman (1987), most ethnography for technology design adopts
a particular flavour of sociology termed 'ethnomethodology'. In short, ethnomethodologists hold that social rules, norms and practices are not imposed externally on
everyday life, but that social order is continuously and dynamically constructed from
the interactions of individuals. As a corollary of this it is philosophically unsound to
generalize beyond the setting where the ethnomethodological ethnography has been
undertaken, or to analyse the findings from a theoretical standpoint.
Ethnographic work in human-centred design projects is not always the preserve of
specialist 'ethnographers'. As the approach has gained popularity, technologists and
HCI practitioners frequently 'do some ethnography' for themselves. Their sometimes
casual adoption of the techniques has attracted some adverse comment from those
trained in the field (Forsythe, 1999), and more cautious practitioners often refer to their
work as 'ethnographically informed'.

.....- ............... -.... -....... -............- ....-■.................... .. -......................... - ........ -.............- J

Chapter 7

Design ethnography is a growing area of research and activity in interaction design. It
recognizes the difference between undertaking ethnographies from an anthropologist’s
perspective (where natural understanding is central) and the ethnographies practised
by designers (where the aim is to inform design). Specialist degrees are now offered
that present the theory and practice of design ethnography.
Workplace studies consist of ethnographies and field studies of the workplace. These
workplaces have included control rooms in the London Underground, the Paris Metro,
air traffic control rooms, and financial institutions, to name but a few. The aim of these
studies is to describe in fine detail (often called richly descriptive) the day-to-day work
of these workplaces. The objectives for the ethnographer are very much determined
by those of the design project in hand. They often focus on elucidating the role and
high-level requirements for a proposed new technology through a deep understand­
ing of work in practice. For instance, Pycock and Bowers (1996) found that ambitious
proposals for virtual reality to support fashion design had ignored the mundane but
essential work that in fact occupied much of the designers’ time. In other projects, the
ethnographer’s ‘added value’ is in the definition of usage stories and scenarios, the iden­
tification of practical issues for implementation and as a focus for a higher degree of
stakeholder involvement (although in some instances, the ethnographers themselves
have acted as proxy users). The discussion in the final chapter of Heath and Luff (2000)
is a particularly clear account of moving from ethnography to requirements using video­
based studies of medical consultations. These contributed to requirements definition
for a patient records system. In explicitly requirements-oriented work, a set of guiding
questions can be useful, such as those shown in Box 7.4.

A guide to practising workplace ethnography
Resource limitations in many projects can support only a limited amount of ethno­
graphic work. There are also ‘political’ issues that are raised by the very nature of an
ethnographic intervention. With these considerations in mind, Simonsen and Kensing
(1997) suggest four preconditions for the use of ethnography in commercial projects:
• Both analysts and user organization must have a positive attitude to investing signifi­
cant resources.
• Stakeholders must be content with the overall purpose of the new system.
Ethnographic approaches, with their emphasis on close work with people, are
unlikely to succeed if there are aims to deskill or replace them.
• Analysts must be prepared to handle the ‘political’ issues which can arise from such
an intervention.
• Areas of focus must be identified (ideally, after an initial period of more opportunis­
tic immersion in the environment).

Rogers and Bellotti’s ‘reflective framework’ for ethnographic

Why is an observation about a work practice or other activity striking?
What are the prosand cons of the existing ways technologies are used in the setting?
How have 'workarounds' evolved and how effective are they?
Why do certain old-fashioned practices, using seemingly antiquated technologies,
persist, despite there being available more advanced technologies in the setting?






Techniques for designing interactive systems

E n v is io n in g fu t u re se ttin g s

• What would be gained and lost through changing current ways of working or carry­
ing out an activity by introducing new kinds of technological support?
• What might be the knock-on effects (contingencies arising) for other practices and
activities through introducing new technologies?
• How might other settings be enhanced and disrupted through deploying the same
kinds of future technologies?
Source: Rogers, Y. and Bellotti, V. (1997) Grounding blue-sky research: how can ethnology help?, Interactions4(3),
pp. 58-63. © 1997 ACM, Inc. Reprinted by permission.



So, how can resources best be organized to maximize the potential of the ethnographi­
cally informed work? A review of workplace studies and our own experience suggests
the following:
• Most can be gained in the early stages when the main design issues are unclear; later
work can be focused by data from interviews and other techniques.
• Most information is obtained where people collaborate in some observable way, and
share information artefacts in real time.
• Multiple analysts can be valuable, both in observing different activities and in com­
bining perspectives on the same activity.
• Video and audio recording is valuable in capturing data, but field notes remain a vital
The key to (relatively) economical ethnographic work is to recognize when enough data
has been collected. One indication o f‘enough’ maybe that no new details are emerging.
Another is being able to identify what has not been observed, but will not happen within
the span of the current work.
Of course, time is required not just to acquire the data but to analyse it. Video
is intensely time-consuming to analyse - at least three times the length of the raw
sequence and frequently more, depending on the level of detail required. The process
can be streamlined by having an observer take notes of significant points in the ‘live’
action; these notes then act as pointers into the video recording. Software tools such as
Adas.ti and Ethnograph help in analysing pages of text notes (not just of observations,
but also transcripts of interviews and group sessions) and, in some cases, audio and
video data. For large projects, material can be organized into a multimedia database or
Web-based repository.

Analysis software
There are a number of software packages that help with the analysis of the rich data
that is gathered through ethnographic studies. Atlas.ti, for example, allows the analyst
to tag pieces of text or video with key words and then to group these key words into
higher-level constructs. This 'grounded theory' approach to analysis aims to let the con­
cepts arise from within the data rather than be imposed top-down by the analyst or
designer. Grounded theory was introduced in 1967 (Glaser and Strauss, 1967), but there
continues to be considerable work in the area.

Chapter 7

Communicating ethnographic results can be challenging. One approach is to encap­
sulate the findings in Vignettes’ - short descriptions of typical scenes. A vignette is very
similar to a scenario but less structured than the format we have proposed - perhaps
more like the text of a scene in a play script, complete with stage directions. The vignettes
are usually accompanied by a transcript of the accompanying dialogue. Vignettes are
often supplemented by video extracts and sample artefacts. Another possibility is for
the ethnographer to act as an evaluator of early concepts or prototype designs, before
the requirements are finalized and while the design is too immature to benefit from
user feedback. A still closer link between workplace studies and system design has been
attempted by the COHERENCE project (Viller and Sommerville, 1998,2000). This takes
the output from the study and expresses its findings in the UML notation (UML is the
Unified Modeling Language). By contrast, Heath and Luff (2000) and Dourish (2001)
argue that the purpose of workplace ethnography is to construct a reservoir of experi­
ence that allows designers to uncover how people make sense of technology in use, and
so to design tools which support the improvised, situated and continually reconstructed
nature of real-world activity.


Artefact collection and ‘desk work’

Data from interviews, questionnaires and observation will have identified a range of
artefacts in the form of things that support an activity. It is often possible to supplement
this by collecting artefacts - such as documents, forms or computer printouts, in office
settings - or to video or photograph items that cannot be removed.
Figure 7.8 shows the sort of photograph which might be taken and annotated to cap­
ture the range of information artefacts used in everyday work in an academic’s office.
These include:
1 Laptop used for file archiving, calendar, document production, e-mail and Internet
2 Paper notebook - notes of ad hoc meetings, also holds currently important papers
3 Printouts of journal articles

F ig u r e 7 .8 Artefacts on and around an office desk
(Source: David Benyon)




Part II • Techniques for designing interactive systems


CD - current backup
(Under mug) miscellaneous documents
Sticky notes with ‘to do’ items, important phone numbers, IP address of laptop
Telephone - internal and external calls
Desktop PC - older file archive, connection to network backup, used for e-mail/
Internet if laptop connection fails
9 Sometimes it can be helpful to track a document through a system, noting everyone
who interacts with it and how the document is amended at each stage - a technique
sometimes known as a ‘tracer study1.
In a study of a health benefits claim processing system, for example, we collected copies
of blank claim forms, standard letters sent to claimants, inter-office memos and the pub­
lic information leaflet about the benefit. By chance, we also found a copy of an article
that provided a valuable insight into health professionals’ views in a local newsletter.
These artefacts helped to ensure that we had a complete understanding not only of the
data processed through the system, but also of their relative importance and signifi­
cance (what information requests are in bold type, what details have to be verified by
a medical practitioner or pharmacist, etc.) and how annotations on the original docu­
ments were used as notes of progress through the system. In another medical example,
this time in a hospital, Symon et al. (1996) show how the very appearance and style of
a doctor’s handwritten notes on patients’ records revealed valuable background details
to other staff, such as whether the consultation had been carried out in a hurry. All such
informal features of the way artefacts are used in practice will make demands on the
design of supporting technology.
Understanding activities does not just involve working directly with the people who
are doing the activity now or who will be in the future. The designer will need to do
plenty of ‘desk work’ as well. Where the brief is to redesign existing technology such as
office systems or home technology products, records of requests for help or user support
can be rewarding sources of data about what is confusing or difficult. Similarly, records
of bugs reported and change requests often reveal gaps in functionality or presentation.
All this can contribute to the new design, but will require interpretation as to which
items represent a genuine need for change. Other desk work involves reading procedure
manuals and other material about the organization. It involves studying existing soft­
ware systems to see how they work and what data is kept. Desk work involves collecting
and analysing any documents that exist and documenting the movement of documents
and the structure of objects such as filing cabinets and ledger books.
Looking at similar products is another way of getting ideas. A market analysis looks
at similar products that have been produced. This can be useful because the designer
can see the product being used in situ and can consider the design solutions that oth­
ers have proposed. This might highlight good and poor solutions for particular design
problems. Looking at similar activities complements such an analysis. An activity might
be in quite a different setting from the one under scrutiny, but might have a similar
structure. For example, looking at a video hire shop might provide inspiration for a car
hire application, or looking at an automatic coffee machine might help in understand­
ing an ATM activity.

Challenge 7.6
What artefacts might you collect or photograph relating to people's use of communications
technologies in the home? (Hint: think about non-electronic media as well.)

Chapter 7 • Understanding

Summary and key points
In th is c h a p te r w e have fo cu sed on so m e w id e ly used te c h n iq u e s fo r u n d e rsta n d in g
peo ple and activitie s in co n text, so w e can id en tify req u ire m en ts on the design o f new
tech n o lo g ie s. H o w ever, th e re is no firm d istin ctio n betw een re q u ire m en ts, design and
eva lu atio n , so m a n y o f th e te ch n iq u e s d e scrib e d h ere co uld be used at vario u s stages
o f the design process. Design starts w ith rese arch in g and u n d e rstan d in g th e situ atio n at
hand, but in the co u rse o f ach ievin g th at u n d erstan d in g , designers iterate b etw een the
exp lo ra tio n o f n e w co n ce p ts an d u n d e rstan d in g an d e va lu atio n o f ideas, designs and
o p in io n s. Using the te ch n iq u e s d escrib ed here sh ou ld en su re th at designers u n d ertake a
h u m an -ce n tred process.

Tech n iq u es fo r u n d erstan d in g people's activitie s in co n text in clu d e in terview s, o b se r­
v atio n an d co lle c tin g sam p les o f arte facts, co m p le m e n te d by b ackg ro u n d research
aw ay fro m the d o m a in o f interest.


Using m o re than o n e te c h n iq u e helps to co m p en sate fo r th e ir in d ivid u al lim itatio n s.
R eq u irem en ts w o rk m ust be d o cu m en ted fo r co m m u n ica tio n and use in design; o ne
w a y o f d o ing th is is a re q u ire m en ts sp ecificatio n su ppo rted by illu strative m aterials,
an o th e r is in d evelo p in g a scen a rio co rpus.


T h e use o f scen ario s starts e a rly in th e design process, w ith th e co n stru ctio n o f c o n ­
cep tu al scen ario s fo r exp lo rin g re q u ire m en ts and illu stratin g th e ir ap p licatio n .


You h ave been co m m issio n e d to design an o n -lin e sh o p p in g an d h om e
d e liv e ry system fo r a n ew s u p erm arke t ch a in . Y o u r clie n ts w a n t th e system to
so m e h o w rep ro d u ce th e best aspects o f real sh o p p in g w ith o u t th e d raw b acks.
T h e y w a n t th e system to app eal to all ad ults w ith access to a h o m e co m p uter.
W h a t te ch n iq u e s w o u ld be su ita b le fo r c a rryin g o u t a req u ire m e n ts an alysis
fo r th e sh o p p in g ap p licatio n ? Explain th e reasons fo r y o u r c h o ice s and an y
po tential lim ita tio n s o n th e co n clu sio n s yo u co uld d ra w fro m th e ir use.


You are d e fin in g fu n c tio n a lity an d in teractiv ity fo r th e n ext g eneratio n o f
m o b ile ph on es. Find a co lleag u e and in te rvie w th em fo r up to 15 m inu tes
ab o u t th e w a y th e y use th e ir c u rre n t m o b ile p h o n e and w h a t e n h an ced
fu n ctio n a lity th e y m ight like. You sho uld m ake notes o f po ints to co ve r
b efo reh an d . H ave th em d e m o n strate th e w a y th e y use th e m ost useful
featu res w ith and w ith o u t a ru n n in g co m m e n tary. Take w ritte n notes o f y o u r
in tervie w ; also use an au d io - o r v id e o -re c o rd e r if yo u h ave o n e availab le. (A sk
th e interview ee's perm issio n first befo re reco rd in g .) R eview th e data yo u have
co llected as soon as po ssible after th e interview .



W h ic h qu estio n s elicited th e m ost useful d ata? W h y?
Did the running co m m en tary provide extra inform ation o r did it obstruct the
dem onstration? Did yo u r interview ee seem com fortable w ith the process?


If yo u h ave reco rded th e in terview , h o w m u ch is m issing fro m y o u r w ritte n
notes w h e n co m p ared to th e reco rding?

If yo u have tim e, c a rry o u t a seco n d in te rvie w w ith so m e o n e else after
refle ctin g on th e results o f th e first.





Techniques for designing interactive systems

3 (More advanced) It is so m etim es argued th at u n d erstan d in g people's existing
activities does not really help to design fu tu re te ch n o lo g ies, sin ce activities m ay
chang e rad ically o n ce th e te ch n o lo g y is in use.



Do you agree o r disagree w ith th is v ie w ? Pro vid e su p p o rtin g arg u m en ts fo r
y o u r p o sitio n .
W h ich req u ire m e n ts e licitatio n te ch n iq u e s are m ost like ly to be effective in
h elp ing users and designers to create the fu tu re? W h y?

4 (More advanced) Read Lu n d b erg et al. (2 0 0 2 ) 'T h e Sn atch er C atch e r' - an
in teractive refrigerator, Proceedings ofNordiCHI '02 (availab le o n -lin e through
th e A C M digital lib ra ry - w w w .a cm .o rg /d l). O u tlin e a design fo r a sim ila rly
p ro vo cative d o m estic d e vice w h ic h is aim ed at stim u latin g p eo p le to th in k
ab o u t th e fu tu re d irectio n s fo r h o m e techn o lo g ies. Explain h o w y o u r design
w o u ld facilitate th e process.


Further reading

A number of general-purpose requirements engineering texts have sound advice on the more
user-centred techniques as well as a strong grounding in the software engineering process. In
particular we recommend:
R o b ertso n , S. and R o b ertso n , J. (1 9 9 9 )

Mastering the Requirements Process. A ddison-

Wesley, H arlow (Chapters 5 and 11).
S o m m e rville , I. and Saw yer, P. (1 9 9 7 )

Requirements Engineering: a Good Practice Guide.

Wiley, Chichester (Chapter 4).
Wixon, D. and Ramey, J. (eds) (1996)

New York. A n

Field Methods Casebook for Software Design. Wiley,

e x c e lle n t , r e a d a b le in tro d u c tio n to g a th e r in g in fo r m a tio n fr o m fie ld w o r k a t u se r

sites, c o n ta in in g m a n y c a s e s tu d ie s w h ic h s h o w h o w v a r io u s te c h n iq u e s h a v e b e e n a p p lie d a n d
a d a p te d . U n fo rtu n a te ly , a t th e tim e o f w r itin g it is n o t e a sy to o b ta in a c o p y to p u rc h a s e , b u t y o u r
lib ra ry s h o u ld b e a b le to tr a c k d o w n a c o p y .

Getting ahead
K u n ia v sky , M . (2 0 0 3 ) Observing the User Experience - a Practitioner's Guide to User
Research. Morgan Kaufm ann, San Francisco, CA. C o n ta in s m u c h se n sib le , p r a g m a t ic m a te ria l
a b o u t w o rk in g w ith p e o p le . N o te , h o w e v e r, th a t m o s t o f th e e x a m p le s a re o rie n te d to w a rd s th e
d e sig n o f w e b site s.

Y. and Bellotti, V. (1997) Grounding blue-sky research: how can ethno-graphy
Interactions, 4(3), 58-63. A s h o r t in tro d u c tio n to e th n o g ra p h y , a th e o r e tic a lly in fo rm e d


a p p ro a c h to o b s e rv a tio n , in th is c a s e a d a p te d to th e d e sig n p ro c e ss.

There are many on-line tutorials for things such as card sorting that are included on the web­
site associated with this chapter at
Also see Boxes and Arrows site at

Chapter 7 • Understanding

Comments on challenges
Challenge 7.1
Requirements 1,3, 6 and 8 are all non-functional - they are all qualities which the HIC must have,
rather than something it actually does. The functional requirements are 2, 4, 5 and 7. Of course,
many non-functional requirements do necessitate some underlying functionality - passwordcontrolled entry, for example.

Challenge 7.2
Think about whether it makes a difference to you personally if you are involved in decisions which
affect your everyday work or home life. We would expect that you would be more enthusiastic
about a holiday, for example, if you have helped to decide whether it should include relaxing on the
beach or visiting ancient ruins, staying in a hotel or camping, etc. If people take part in the speci­
fication and design of a system, they are more likely to use it effectively once it is implemented.
There is strong research evidence to support this.

Challenge 7.3
There are several limitations to interviewing. They include:
• People can only tell the interviewer about aspects of current activities of which they are aware.
This excludes parts of the job (or whatever) which are so familiar that they no longer penetrate
into consciousness, aspects beyond the interviewees' direct experience, etc.
• Emphasis on correct, official procedures
• Memory
• Difficult-to-describe complex operations.

Challenge 7.4
(a) The focus may not be clear to everyone. E-mail (and older utilities such as FTP - file transfer
protocol) run over the Internet, but many people may simply think of the WWW. The question
should make it obvious what is intended: perhaps 'How often do you access the WWW (World
Wide Web) or use e-mail?'. Better still, use separate questions for each, since usage levels are
likely to be different.
The word 'typically' or 'normally' should be included when asking about usage, unless you
are interested in a snapshot of a specific time period.
There is no provision for 'never'.
(b) • 'Frequently'is likely to be interpreted in different ways.
• It is much easier for people to check items on a list of possibilities rather than recall them.
• Providing a list also makes it easier to analyse the responses. You can include an 'other please specify' item to catch any types of material you had not expected.
• You may well have identified additional points.

Challenge 7.5
No specific comments - the idea is to gain experience in observation. This variant, where the
observer is also part of the group being observed, is termed 'participant observation'.

Challenge 7.6
Possible artefacts to be collected: printouts of typical day's e-mail and e-mail address book, with
notes of the contact's relation to the owner of the address book, screen printout showing WWW
favourites, etc. And to be photographed: landline phone(s) and fax machines in normal location(s)
with any directories, address books, notepads and so on kept near the phone; similarly the home
PC if used for communications, etc. Mobile phones are probably only worth photographing if
novel features are used which can be captured in the photograph. It would also be useful to draw a
sketch plan showing the location of the various communication devices within the home.


Chapter 8
Envisionm ent


Finding suitable
representations 167

E n v is io n m e n t is c o n c e rn e d w ith m a k in g id e as v is ib le ; w ith e x te rn a liz in g
th o u g h ts. E x te rn a liz a tio n ca n ta k e all m a n n e r o f fo rm s : s to rie s an d

8.2 Basic techniques 168

s c e n a rio s, p re s e n ta tio n s , s k e tc h e s, fo rm a l m o d e ls, s o ftw a re p ro to ty p e s,

8.3 Prototypes 175

c a rd b o a rd m o d e ls a n d so o n . D iffe re n t fo rm s o f re p re s e n ta tio n w ill be

8.4 Envisionm ent in practice 180

m o re o r less u se fu l a t d iffe re n t stages in th e d e sig n p ro c e ss a n d m o re

Sum m ary and key points 184

o r less e ffe c tiv e fo r d o in g d iffe re n t th in g s. A fo rm a l p re s e n ta tio n o f a

Exercises 184

d esig n c o n c e p t fo r a p o te n tia l c lie n t w ill lo o k q u ite d iffe re n t fro m a

Further reading 185

sk e tc h o f a s c re e n la y o u t in te n d e d to e x p lo re w h a t s o m e th in g w ill lo o k

W eb links 185
Com m ents on challenges 185

like. E n v is io n m e n t is n e e d e d to re p re s e n t d esig n w o r k to o u rs e lv e s an d
to o th e rs. It o c c u rs th ro u g h o u t d e v e lo p m e n t as th e d e s ig n e r g e n e ra te s
m u ltip le d e sig n s o lu tio n s a n d w h ittle s th e m d o w n to a fin a l p ro d u c t.
In th is c h a p te r w e c o n s id e r th e p rin c ip a l e n v is io n m e n t te c h n iq u e s ,
v a rio u s fo rm s o f p ro to ty p in g u sed to e x p lo re a n d e v a lu a te id e a s an d
th e p re s e n ta tio n o f id e as to c lie n ts . B u t first o f all w e re v ie w w a y s o f
th in k in g a b o u t th e id e as to b e e x te rn a liz e d .
A fte r s tu d y in g th is c h a p te r y o u sh o u ld be a b le to :

U se a v a rie ty o f te c h n iq u e s fo r e n v is io n in g d esig n p ro b le m s an d
p o ssib le so lu tio n s


U n d e rs ta n d th e ro le o f c o n c re te s c e n a rio s in e n v is io n in g d e sig n


S e le c t a n d u se a p p ro p ria te p ro to ty p in g te c h n iq u e s


U n d e rs ta n d th e m a in fa c to rs in c o m m u n ic a t in g d e sig n s e ffe c tiv e ly .

Chapter 8 • Envisionment

8.1 Finding suitable representations
Envisionment is fundamental to effective human-centred design, to enable designers
to see things from other people’s perspectives and to explore design concepts and ideas
with others. Different representations of design ideas are useful at different stages for
different people. They help with generation, communication and evaluation of ideas.
A sketch ‘on the back of an envelope’ might be useful for generating an idea and express­
ing it to a colleague - but it is not so good for giving to a client.
There are many techniques that can be used to help develop an understanding of
the design problem and to envision possible solutions. None of these techniques
in themselves will lead to the perfect design, but they will all generate some kind of
document or representation that can be used in the process of communicating with
clients, customers and colleagues. It is through communication that design solutions
will arise, be evaluated, and (eventually) be transformed into a final product.
Which techniques are used on a particular project will depend on a number of factors:
the working style of the development team, the type of project, the resources available
and so on. In an ideal world, developers would use a wide variety of representations,
but in a two-person company working on a project with a deadline of four weeks this
may not be possible.
Choosing suitable representations for the task at hand is one of the skills of a designer;
another is making good use of that representation. Representations work by suppress­
ing unnecessary detail, thus ensuring that the significant features of some artefact or
activity stand out. A good representation is accurate enough to reflect the features of
the system being modelled, but simple enough to avoid confusion. It adopts a style of
presentation that is suitable for its purpose.
Consider the following example:
A car designer has been com m issioned to produce a new luxury sports car. He or she
doodles a few designs on paper and shows them to other designers on the team . They
m ake som e co m m ents and criticism s and as a result changes are m ade. Fin ally the
designer is satisfied with one of the designs and draws up detailed blueprints that are given
to the firm's m odel maker. Scale models are produced and sent to M arketing and Sales
for custom er reaction. The scale models are also subjected to w ind tunnel experim ents to
investigate the aerodynam ics of the design and the results are used in a com puter program
that w ill calculate the car's speed and fuel efficiency.

The designer is using four different representations in at least four different ways:
1 The original representations focus on clearing the mind. In this case they are doodles
and sketches that are used to generate new ideas, examine possibilities and prompt
for questions.
2 The blueprints given to the model maker and the scale model given to the Marketing
and Sales departments are suitable for accurately expressing ideas to others.
3 The wind tunnel experiments show representations being used to test ideas.
4 The computer model is used to make predictions.

Challenge 8.1
Which representations in the example above are being used to explore the problem?
Which are being used to communicate ideas?

------- --

- ------



.................. .....


.................... - .................................................... -

................................................ - - - - - ....................................




Techniques for designing interactive systems

An outline envisionment process
Here is a suggested series of steps for the envisionment process, pulling together the
wide-ranging material in this chapter.
1 Review requirements and conceptual scenarios.
2 Develop representations of your design ideas. At a minimum these should include
concrete scenarios, storyboards developing the main interaction sequences, and
snapshot sketches of key screens or other aspects of the product.
3 If your product is a new one, experiment with different metaphors and design con­
cepts through your representations (see Chapter 9).
4 Explore design ideas with the people who will be using the system wherever possible
(using techniques described in Chapter 7).
5 Develop wireframes to provide more detail on the proposed structure and navigation
(this chapter).
6 Iterate and gradually formalize the design (making it more concrete) through proto­
types and further evaluations.


Basic techniques

Envisionment is about bringing abstract ideas to life. It is easy to have great ideas in your
head, but it is only by envisioning them that the flaws and difficulties will be exposed.
There are a number of basic techniques that can help.

Sketches and snapshots

The full scenario is in
Chapter 6

Interactive visualizations
are discussed in Chapter 12


The art of sketching is something that all designers should practise. Ideas and thoughts
can be quickly visualized - either to yourself, or to others - and explored. The Millennium
Bridge across the River Thames in London was reputedly designed on a paper napkin in
a restaurant. Designers do well to carry a sketchbook with them so that inspiration can
be quickly captured and preserved.
Figure 8.1 shows two visualizations of the Edinburgh Festival scenario from the HIC
case study. A key design requirement for this system was to display large amounts of
data without the need for scrolling (in order to move away from the personal computer
paradigm). In the sketches we can see that the designer has been exploring different
ideas for displaying and searching through results of a search. The design principle
underlying the designs is often referred to as ‘focus and context’. Ben Shneiderman has
a mantra for visualizations of large amounts of data that he encourages designers to use:
‘overview first, zoom and filter, then details on demand’ (Shneiderman, 1998, p. 523).
On the left is a ‘hyperbolic tree’ representation of the Festival scenario and on the right
is a ‘cone tree’ representation. Notice how the hyperbolic tree is better for capturing the
focus and context principles.
Individual snapshots of a design can be provided to show key moments in an inter­
action (e.g. Figure 8.2) and are particularly useful for exploring the impact of a cer­
tain style or design. Snapshots can be single sketches, or frames, from a storyboard (see
below) or they can be produced using software.

Challenge 8.2
Sketch two different ways in which you might present information about tourist sites on a
town's website.

--------- --------- ----------- --------------------- - - - ----------- ----------------------- — J

Chapter 8 • Envisionment

Figure 8.2 Individual snapshots of a design
(Source: David Benyon)

Storyboarding is a technique taken from filmmaking - using a simple cartoon-like
structure, key moments from the interactive experience are represented. The advan­
tage of storyboarding is that it allows you to get a feel for the ‘flow’ of the experience.
It is also a very economical way of representing the design - a single page can hold
6-8 ‘scenes’. It is often helpful to sketch out a storyboard based around a concrete
scenario. The two together are very helpful in working through design ideas with
Three main types of storyboarding are commonly found in interactive media design:
• Traditional storyboarding. A storyboard for a film would usually have some notes
attached to each scene expanding on what will happen - this helps overcome the
limitations of representing a dynamic experience in a static medium. For interactive
systems, notes below each sketch usually contain the relevant steps from a scenario,




Techniques for designing interactive systems

and the sketches themselves are annotated to indicate interactive behaviour. This is
the most usual form of storyboard if there is not a strongly multimedia flavour to the
• Scored storyboards. If the application has a lot of motion graphics the storyboard can
be annotated - a sketch is annotated with appropriate notation and notes about, for
example, type, colours, images, sound and other issues are attached underneath.
• Text-only storyboards. These are useful if the application has a lot of very complex
sequences. You can specify what images appear, what text accompanies them, any
accompanying media, general notes about tone, flow, etc.
Figure 8.3 shows a sketched storyboard for an application of the HIC to playing MP3
music files. The storyboard shows how an interaction might take place. It exploits some
ideas of marking movement using arrows and lines to indicate change. Figure 8.4 shows
part of another storyboard, this time for a website designed to showcase a photogra­
pher’s portfolio.

Mood boards
Mood boards are widely used in advertising and interior design. Quite simply you gather
visual stimuli that capture something of how you feel about the design - photographs
and other images, colours, textures, shapes, headlines from newspapers or magazines,
quotations from people, pieces of fabric and so on. Attach the stimuli to a pinboard.

Chapter 8 • Envisionment

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storyboard for a
photographer's website

Even thinking about their arrangement can stimulate ideas. You can put pages from
websites you like on mood boards. If you use Blu-Tack or something similar then you
can add and delete items as your thinking changes. Figure 8.5 shows an example from
Lucero (2009) of an interactive system that supports the presentation of mood boards,
the ‘Funky Wall’.

Figure 8.5 Funky Wall
(Source: Lucero)



Techniques for designing interactive systems

The rule with mood boards is that ‘anything goes’. The point of the board is not to
formally represent some aspect of the design, simply to act as inspiration - perhaps
promoting a particular line of thought, or providing inspiration for a colour scheme.
One technique is to get the client to create a mood board. This can give you an insight
into the kinds of aesthetics that are likely to appeal to them. As a variation on the mood
board concept, writing down adjectives that describe some aspect of the system can be

Navigation maps
-> Chapter 14 discusses
navigation for websites
Chapter 25 discusses
navigation in general

Navigation is a key feature for many systems. Navigation maps focus on how people
move through the site or application. The aim is to focus on how people will experience
the site. Each page in the site, or location in the application, is represented with a box
or heading and every page that can be accessed from that page should flow from it.
A useful tip is to put in all flows possible (i.e. back and forwards from a page) as this
will highlight sections where people might get stranded. Navigation maps can usefully
be redrawn many times through the project life cycle, as poor navigational structure
is one of the main reasons people turn off a website, for example. The maps can be
used with scenarios to “walk through’ particular activities and are a very good way of
spotting poor aspects of design such as ‘orphan pages’ (pages which are not accessible)
or dead ends.
Navigation is important in all manner of applications and products, not just websites.
Figure 8.6 shows the navigation map for a mobile phone. More formal and more fully
annotated maps can also be developed as illustrated in Figure 8.7. Arrows can be added
to lines if the direction of a link is important.

M enu m ap
Items in italics depend on your subscription and your network operator.

i N etw ork Services
• Inform ation

i Phone Book
■Add nam e

•Voice dishing
•My card
•O w n num bers
• fix e d dialling

i M essag es
•Inbo x
•O utbox
•W rite n e w
•Settin gs
•D raft texts

•Call costs
•Line selection

Figure 8.6 Mobile phone navigation map
(Source: Trium phone manual, Mitsubishi)

Chapter 8


Figure 8.7 Navigation map for a website

Wireframes are outlines of the structure of a software system. They used to be concerned
principally with website design, but with the proliferation of small-scale apps for handheld
and tablet devices, wireframing has become a mainstream technique. With the develop­
ments of Cascading Style Sheets (CSS) and the specification language HTML5, the devel­
opment of websites and the development of apps are becoming increasingly blurred
Just as navigation maps focus on how pages are structured and linked together, so
wireframes focus on the structure of particular types of pages. Use the two together and
you have the basics of an app or website design.
Wireframes work because they focus on the general elements of a design without
worrying about the final detail. For example in a mobile phone app there are buttons,
menu items, selections. Certain events cause certain behaviours such as a button
click moves the user to the next page. Wireframing makes use of these generic design
features for both apps and websites to create quick designs often for quick evaluation.
The storyboard in Figure 8.3 is an informal wireframe.
Software packages are available to help with developing wireframes. The best known
is Axure ( but there are a number of other alternatives. These provide
templates that constrain the design to the particular size and style of a particular deliv­
ery platform such as an iPhone. Good advice on interface design for the iPhone and iPad
are provided on the Apple website.
Wireframes sit in between the informal sketching of this section and the development
of prototypes described in the next section as there are several software packages that
will generate working prototypes from the wireframe. Some examples of wireframes
are shown in Figure 8.8.

Challenge 8.3
Construct a navigation map for a website with which you are familiar - perhaps that
of your university/college or employer. (If the site is very large, draw a partial map.)
Are there any 'dead ends' or complicated routes to important information?
..................................... -

.................................................... .............. ............ .............................. .......................i


C h ap ter 12 deals w ith
visual interface design



Part II • Techniques for designing interactive systems

PACT i.D .


lo g o

Com pany Name

E -m a il N e w sle tter

Month, year







L in k to a

fu ll length article

Figure 8.8 Examples of wireframes
(Source:, SmartDraw)




More News



D irect Lin k to
each full-length
lis t

C ontact
Inform ation

Chapter 8

These are just a few of the many possible envisionment techniques. These techniques
are filtering mechanisms for the designer, effectively screening out parts of the design
space that the designer does not want to explore in order to focus on the parts that are
of interest. There are books full of interesting and novel ways of representing aspects
of design. For example, ‘mind maps’ list the main concepts of a design, showing links
between them, flow diagrams show the movement of some items or some information
through a design, and transition diagrams show how a system changes from one state
to another. We discussed an example of a car designer who used sketches, and others
in the design process who used scale models, blueprints and so on. We also argued
that getting an appropriate representation - appropriate for a particular purpose in a
particular context - is important. The different representations will be used alongside
other techniques for helping to generate ideas such as brainstorming and other forms
of collaborative design. For example, we have found sketching on a whiteboard very
effective for a design meeting, as is using a flip chart where pages can be torn off and
stuck to the wall. Writing ideas on Post-it notes and sticking them on the walls of a
design room is another technique. They can be rearranged to show different collections
and ‘affinities’. Collaborative writing, where a group all work on a single document
using a computer and data projector to display the results on a screen, can be very
effective in producing draft documents.
A key feature of design and of the techniques described here is not to sit staring at a
blank piece of paper. Getting inspiration from magazines, websites, software systems,
other people, similar systems or products and so on (the importance of examples
in design (Herring et al., 2009)), and externalizing ideas through envisionment
techniques, are the first steps in design.

. ------------................- - .................................................................

8.3 Prototypes
A prototype is a concrete but partial representation or implementation of a system
design. Prototypes are used extensively in most design and construction domains. Lim
et al. (2008) present a view of prototypes as ‘tools for traversing a design space where
all possible design alternatives and their rationales can be explored . . . Designers com­
municate the rationales of their design decisions through prototypes. Prototypes stimu­
late reflections, and designers use them to frame, refine, and discover possibilities in a
design space’ (p. 7:2).
Prototypes may be used to demonstrate a concept (e.g. a prototype car) in early design,
to test details of that concept at a later stage and sometimes as a specification for the final
product. A prototype may be made of something as simple as paper, cardboard or other
suitable material, or it maybe developed using a sophisticated software package.

Prototyping the lunar lander
The engineers in the Apollo missions built a full-size cardboard prototype of the lunar
landing module to test the position and size of the windows in relation to the field of
view of the astronauts. This experimentation led to the design decision that the astronauts
would stand (not sit) inside the lander - thus allowing windows to be smaller and saving
crucial weight.





Techniques for designing interactive systems

In our domain of interactive systems design, representations such as screen sketches
and simple early prototypes blend into each other. But the main distinguishing char­
acteristic of a prototype is that it is interactive. Something happens when a person
‘presses’ a ‘button’ - even if the button is drawn on paper and the action consists of a
menu on a Post-it note being added by the designer. The appropriateness of a prototype
will depend on a number of factors such as whom the prototype is aimed at, the stage of
the design process and what features the designer is looking to explore.
For the design team, representations like navigation maps and flow charts might
be meaningful, but for clients and ordinary people some form of prototype is crucial
for capturing the outcomes of the envisioning techniques we have discussed so far.
The prototype might seek to highlight just the interface, or some crucial aspect of the
functionality. Prototypes are first and foremost a way of involving people and clients
in evaluating your design ideas. There are two main kinds of prototyping - low-fidelity
(lo-fi) and high-fidelity (hi-fi). We also include a section on video prototypes, a medium
that is becoming increasingly useful and common in interaction design.

Hi-fi prototypes
Hi-fi prototypes are similar in look and feel, if not necessarily in functionality, to the
anticipated final product. They are produced in software, whether in the development
environment which will be used for implementation or in packages that will allow inter­
active effects to be mocked up easily. Hi-fi prototyping has the following features:
• It is useful for detailed evaluation of the main design elements (content, visuals,
interactivity, functionality and media) - for example, hi-fi prototypes can be used
in usability studies to establish whether people can learn to use the system within a
specified amount of time.
• It often constitutes a crucial stage in client acceptance - as a kind of final design
document which the client must agree to before the final implementation.
• It is generally developed fairly well into the project when ideas are beginning to firm
up, unless there is some crucial issue that needs to be resolved before any other work
can proceed.
A problem with developing hi-fi prototypes is that people believe them! This is dangerous if
the designer has not checked details and thought through ideas clearly beforehand. A sim­
ple error - perhaps in the name of a customer, or of a product - can completely ruin a pro­
totype because clients or employees will get confused. If everything else seems real, why
aren’t the customers our real customers? It is no good saying “we were going to fix that’ or
‘that is just a place holder’. For hi-fi prototyping, accurate detail is vital. Another problem
with hi-fi prototyping is that it suggests such a system can be implemented. We have found
it impossible to implement in Java some effects that were prototyped using Macromedia
Director, for example. Inevitably a degree of effort and time is consumed in producing the
prototype. If this is in the eventual development environment, developers can be under­
standably reluctant to discard work on features rejected in exploring the prototype.

Lo-fi prototypes
Lo-fi prototypes - often termed paper prototypes, since that is what they are usually
made from - on the other hand, have the following features:
• They are more focused on the broad underlying design ideas - such as content, form
and structure, the ‘tone’ of the design, key functionality requirements and naviga­
tional structure.

Chapter 8

• They are designed to be produced quickly, and thrown away as quickly.
• They capture very early design thinking and should aid, not hinder, the process of
generating and evaluating many possible design solutions.
The products of some of the envisioning techniques discussed previously are kinds of
lo-fi prototypes in some respects. However, the most usual form of this sort of proto­
type is a series of ‘screenshots’ that people can ‘walk through’ (for example, a button
on screenshot 1 can be ‘clicked’ and this is followed by screenshot 6, etc.). How the
prototype is implemented is limited only by your imagination, by time and the mate­
rials readily to hand. Very flexible prototypes can be produced simply and quickly
using screen-sized pieces of stiff paper and index cards or Post-its in different colours.
Permanent features of each screen are drawn on the card; dynamic items such as dia­
logue boxes or menus use the cards or Post-its, cut to size as necessary. Overlays of ace­
tates can simulate dynamic features, or allow people to write comments using wipe-off
pens. But it is really important not to spend too much time doing this - the whole point
is the low investment in the prototype build. If you are spending a good deal of time try­
ing to replicate design details on paper, you should probably be using a hi-fi software
prototype instead.
Figure 8.9 illustrates a lo-fi prototype developed to explore ideas for a tool to allow
households to communicate directly with local government. One feature to note here
is the small acetate just visible at top left, which allows people to record suggested

Figure 8.9 Paper prototype of a messaging screen for a home communications centre
(Source: David Benyon)

Paper prototypes
Paper prototypes are widely used in
practice. A survey of 172 usability pro­
fessionals conducted in 2002 asked
how important they considered the
technique to be in their work (Snyder,
2003). The responses are shown in the
chart below - a 'useless' option was
included but no one chose it. (The
percentages do not sum to 100 per
cent because of rounding.)







Part II • Techniques for designing interactive systems

The main practical issues with designing paper prototypes are as follows:
• Robustness. If a paper prototype is to be handled by lots of people it needs to be tough
enough to survive.
• Scope. Focus on broad issues and key elements; if you are trying to tell too detailed a
story it can be hard for users to understand.
• Instructions. There is a trade-off between adding enough detail for someone to be
able to use the prototype without the designer helping (in which case the boundary
between the design ideas and the supplementary information can be hard to see)
and adding so much detail that it needs someone to talk the person through it (which
may affect their responses).
• Flexibility. Have parts of the paper prototype adjustable so that people viewing it
can ‘redesign it’ on the fly, e.g. by using sticky notes to represent parts of the screen
where the user can move elements around or add new items.

Video prototypes
For over 20 years researchers have highlighted the potential of video as a tool within
the participatory design process, from initial observation, through ideas generation and
design exploration, what Mackay et al. called ‘video brainstorming’ and ‘video proto­
typing’ (2000). Vertelney’s method (1989) involves the creation of a physical mock-up
model of the product; a video is then shot with an actor interacting (or ‘acting’) with the
model as though it were fully functional. The product’s display dynamics are simulated
in an animation program, and are superimposed (or composited) on the video, ensuring
synchronization to give the appearance that the product is actually responding to the
person’s actions.

Challenge 8.4
You are a designer working on a new interface to a supermarket's on-line shopping
system. The client wants a complete revamp of the site. Your team leader in your own
organization, a software developer, is unconvinced of the value of using lo-fi prototypes
to explore ideas. Write the text of a short e-mail to convince her that this is a good idea.
(Only the main part of the text arguing the case is required.)
■ .^ ■ M M M iiM im n in iin n iii

mi i in rimnnTTi nmTiiTmrrni

n------------ —

----------- ---- ------------------------------------------- ------------

The second method suggested by Vertelney is what is sometimes referred to as the
‘weatherman’ technique, where a video image is superimposed onto computer graphics.
Actions are captured against a blue screen (typically a green screen is used now), allow­
ing removal of the background (via chromakey colour removal) and the superimposition
of the video image onto a pre-modelled 3D environment. With appropriate real-world
camera movement synchronized with parallel movement within the virtual environ­
ment, the resulting composite can have a powerful effect.
What has changed in video prototyping are the tools used to create the video mate­
rial. The technology and computing power used for the production of ground-breaking
Hollywood visual effects, such as the liquid metal T1000 in 1991’s Terminator 2,
are now available to the sub-£1000 consumer market. The software tools used in
professional film and television production, such as Final Cut Pro (editing and post­
production) and Shake (compositing) as well as Adobe’s After Effects (3D animation
and rendering) are all well within educational budgets (all are available below £500

Chapter 8 • Envisionment

with higher education discounts). Furthermore, the advent of technologies such as
HDV (High Definition Video), the successor to the ubiquitous mini-DV tape format,
has brought high-definition capability at consumer price. The bottleneck is not with
the video production hardware or software now, but rather with the skill of the pro­
duction team. As the Australian film critic Shane Danielsen said at the opening of the
Edinburgh Film Festival in 2006, ‘The emergence of digital filmmaking puts the tools
in the hands of anyone, but not the talent’. And, of course, the ability to put films into
the public arena on sites such as YouTube can elicit wide-ranging reactions to design
An example of video prototyping comes from a project investigating embodiment
issues of the concept of a companion based on the following conceptual scenario:
Lexi is a 3D projected figure that helps its guardian, Tom, by scheduling his personal
and work life, keeping him up to date with relevant news articles and being first point of
contact for e-mails, phone calls, text messages and the like. Lexi is a mobile companion
who can 'leap' from technology to technology as necessary but is most fully realized when
projected as a 3D figure on Tom's tablet.

Using a modelling application such as e-Frontier’s Poser 7, it is possible to apply multi­
ple figures to a baseline video track in identical fashion. Because the animation uses the
same underlying kinematics and basic bone structure, it is possible to investigate the
impact of the single variable of character embodiment. As can be seen in Figure 8.10, it
is possible to composit different characters onto the baseline video of the companion’s
owner (actor) Tom, all of which behave identically but look completely different - in
this example, a penguin, a man and a woman. In parallel to this is the ability to alter
the vocal characteristics of Lexi, for example pitch, tone, naturalness, etc. By applying
this multi-layered approach it is possible to produce extremely quickly multiple videos
which have only one variable changing from the base line.

Different approaches to functionality in prototypes
There are several other types of prototype that it is useful to distinguish. A full proto­
type provides full functionality, but at a lower performance than the target system.
A horizontal prototype aims to go across the whole system, but deals only with top-level
functions, so much of the detail is omitted. In contrast, a vertical prototype implements
the full range of features, from top to bottom, but is applied to only a small number of
functions of the overall system. Combinations of these are common. Evolutionary and
incremental (a more step-wise version of evolutionary) prototypes eventually develop
into the full system.

Figure 8.10 Different embodiments of a companion



Part II • Techniques for designing interactive systems

H S iJ H
S S * * ' 4


Envisionment in practice

In using the prototype, designers sit alongside the people who will use the final sys­
tem to make the prototype ‘work’ if it is a lo-fi version. It helps to have two designers,
one to ‘play computer’ and one to make notes. Whatever the type of prototype, record
comments and design issues as they arise. Videotape can sometimes be useful if there
is likely to be a substantial quantity of detailed feedback for other members of the
People find it difficult to react to a prototype if it is just placed in front of them devoid
of any context. Some sort of structuring narrative is required. The most common strat­
egy is to have people step through a scenario using the new application or to try carry­
ing out one of their current tasks if the application is to replace an earlier system. For
interface design details, set the scene by suggesting what someone would be trying to do
with the software at that particular point, for example ‘You are interested in buying the
shirt shown on this screen but want to know more about the material - show me what
you would do now1. It is always best if people interact with the prototype themselves,
even if only by pointing to a paper button. This promotes engagement with the ques­
tions to be explored, and avoids any danger of the person running the prototyping ses­
sion misinterpreting responses. But there will be cases where this is not feasible. Perhaps
the prototype software is fragile, or the prototype is at a very early stage with very little
genuine interactivity. Here designers can run a video prototype produced in software
such as Director, Keynote, PowerPoint or Flash to simulate a usage session. The movie
can be paused for discussion as appropriate. (What is happening here is, of course, early
evaluation, so many of the techniques discussed in Chapter 10 are appropriate.)

Prototypes and participatory design

« - C h ap ter 6 describes the
H IC case study

Lo-fi prototypes are an essential part of participatory design because people cannot
always understand formal models, but they can explore and evaluate ideas through
engaging with prototyped systems. People can also be directly involved in prototype
design. During the development of the HIC we ran a workshop with schoolchildren
f ro r n a school in Dumfries and Galloway in Scotland. It was decided to use the existing
scenarios as stimuli in a participatory design workshop with a group of 20 high-school
students. Using the ‘what will we do tonight’ scenario as a basis, we spent a morning
working with the students. The scenario was adapted to make it more relevant to the
participants - the students were asked to imagine that they and a group of friends had
won a trip to the city for the day and had to plan their activities.
We asked participants to use a range of supplied craft materials and information
examples to create a mock-up of how they thought the HIC would look and operate.
A number of lo-fi prototypes were quickly produced (Figures 8.11 to 8.13).

Trade-offs in prototyping
As with so many aspects of design, the designer has to consider the trade-offs in terms
of time, resources, the aim of the evaluation, the stage of the project and so on. Indeed,
when reflecting on how and what to prototype, the designer should think in terms of
the PACT elements - people, activities, contexts and technologies. Who is the prototype
aimed at? What is the designer trying to achieve with the prototype? What stage of the
project are things at and what is the context for the use of the prototype? What tech­
nologies (hi-fi or lo-fi) are appropriate?

Chapter 8 • Envisionment

Figure 8.11 HIC mock-up in clay (and pencil!)

Figure 8.12 Storyboard

(Source: David Benyon)

(Source: David Benyon)

Figure 8.13 Remote control mock-up
(Source: David Benyon)

Rosson and Carroll (2002) highlight some of these trade-offs:
• High-quality graphics and animation can be used to create convincing and exciting
prototypes but may also lead to premature commitment to some design decision.
• Detailed special-purpose prototypes help to answer specific questions about a design,
but building a meaningful prototype for each issue is expensive.
• Realistic prototypes increase the validity of user test data, but may postpone testing,
or require construction of throw-away prototypes.
• Iterative refinement of an implementation enables continual testing and feedback,
but may discourage consideration of radical transformations.
Prototyping is used throughout the design process.
‘Requirements animation’ is a term used to describe the use of prototyping to illus­
trate requirements. Used at an early stage, a quick prototype can be developed and
shown to the client/users for comment on the general design.
Rapid prototyping (also known as ‘throw-it-away’ prototyping) is common in user
interface design where software such as PowerPoint or Keynote is used to illustrate con­
cepts. The prototype will be ‘thrown away* because implementation will be in a different
language. However, as one famous quotation in software development has it, ‘You will
throw away your first few designs, so you might as well plan to throw them away in the
first place’.


Part II • Techniques for designing interactive systems

Use cases are introduced
in Chapter 3

Use case prototyping is when a ‘polished’ video is produced to disseminate to a wider
audience and also to the software and hardware development teams whose job it is to
bring the product into existence. The power of this type of video to communicate design
requirements in product design as well as software engineering is extremely strong
(Mival, 2004). In certain designs this use case will employ a technology beyond what is
possible (in the Lexi example, a 3D projection smart pad); we have coined these ‘Future
Now’ movies.

Challenge 8.5
Imagine you are presenting your ideas for a diary tool on a smartphone to a small team
of developers from the smartphone manufacturer. What type of prototype would you use?

Prototyping tools
Given the wide range of uses for prototyping and the large number of occasions when
it is used, it is not surprising that there are a wealth of software ‘tools’ that can be used.
A good prototyping tool should:
• Allow easy, rapid modification of interface details or functionality
• For designers who are not programmers, allow direct manipulation of prototype
• For incremental and evolutionary prototypes, facilitate reuse of code
• Not constrain the designer to default styles for interface objects.
Useful tools for requirements animation include paper, PowerPoint (e.g. for illustrat­
ing main screens) and drawing packages. Data manipulation languages such as SQL
can be effective in animating the functionality of a system, and vertical or horizon­
tal prototypes can be built using simple application builders such as Visual Basic, the
Borland development environment, the Java development environment and so on.
User Interface Design Environments (UIDEs) are collections of tools that help designers
rapidly prototype aspects of the interface.
Throw-it-away (rapid) prototyping emphasizes rapid evaluation and changing
requirements. Useful software here includes InDesign and similar tools, Visual Basic,
PowerPoint, hypermedia tools and Web tools such as Dreamweaver or Flash. For
evolutionary and incremental prototyping there is a compromise between produc­
tion and prototyping and a long-term view of system development, so a development
environment that can be used for implementation is needed. Reuse of code is likely and
hence object-oriented languages are suitable.
Prototyping functionality in software has its own pitfalls. For example, if the interface
prototype diverges from the functional prototype it may not be possible for them to be
brought together. Indeed this is what happened in the HIC case study and we finished
up with an interface prototype that was low in functionality and a functional prototype
that had a pretty poor interface! Other dangers include people being unable to evaluate
functionality because the interface is distractingly difficult. In one project participants
in an evaluation of an early prototype of a virtual environment found it so difficult to
move around that reviewing the functionality was practically impossible. People found
it impossible to find their way around fixtures and fittings (as in the virtual bridge in
Figure 8.14), became irretrievably stuck midway up a virtual staircase or entangled
themselves with railings. We recovered the situation by refocusing the early evaluation

Chapter 8

Figure 8.14 The virtual
bridge in a training simulator

sessions on interaction mechanisms and considering functionality much later, when the
worst problems had been resolved. Incidentally, this illustrates the value of prototyping
with people as early as possible in the process. The software designers themselves had
naturally experienced no problems with virtual movement.

Challenge 8.6
What are the advantages and disadvantages of prototyping software at the very early
stages of development?

.... -.................................. ..... - - - - - .................................... — - ... ......................... - - - j

Presenting designs
Presenting design ideas clearly and appropriately is a key skill of the designer. The design
process is a long one, with many different stages, there are many different people
involved and there are many different reasons for giving a presentation. The combina­
tion of these will affect what sort of presentation and what sort of representation are
If the ideas are aimed at senior management, for example, then it is likely that the
focus is on vision, concepts and key features of design. People in this position are gen­
erally concerned with strategic issues rather than detail, so a presentation to manage­
ment should focus on impact, image and concept. If the presentation is aimed at the
client then one would expect a bit more detail and some idea of how it works. If the
presentation is aimed at end-users then it is most likely to concentrate on the detail
of the design and the workings of the system. If presenting to the people who will be
using the system it is important to beware of misconceptions about current activities.
It is very easy for people to lose credibility with such an audience if an unrealistic sce­
nario or example is used.
The purpose of the presentation is equally important. If the aim is getting the contract
then the presentation should focus on the big selling point and what it is that distin­
guishes your design from the others. If the contract is organized and the aim is agreeing
the concept, then the focus will be on restating the client’s brief, clarifying requirements
and scoping the area. Where the presentation is concerned with evaluating a general




Part II • Techniques for designing interactive systems

-» Chapter 9 discusses
design languages

design idea, or with testing major design features with users, then it must be focused on
eliciting an appropriate response.
If the prototype or design is still at the concept stage, broad images of the system are
appropriate, with little functionality except in key areas. An early design will emphasize
the design principles and the basis of the design language. It will show how the parts fit
together, basic navigational features and so on. If it is a detailed design then the correct
size is important, along with the proposed shapes, colours and text.
Finally it is important to be clear about what is being highlighted by the presentation.
Is it the functionality and events, or is it the interactions and usability with the focus on
look and feel, or ease of use? If the focus is on content and structure, then attend to what
information is there, and how it is organized, whereas if it is style and aesthetics then
the focus is on features such as enjoyability, visual and tangible design and use of media.

Summary and key points
Envisionment and prototyping bring designs to life for both designers and the people
who will use the new designs. Prototypes can be anywhere along the spectrum of tech­
nical sophistication, be put together in half an hour or take several days of program­
ming. The point is to explore ideas, not to build an entire parallel system or product.
Prototyping is at the heart of a human-centred design process.
• Envisionment - the making concrete of design ideas - is a key feature of design. All
aspects of the system can and should be envisioned: concepts, functions, structure,
• Envisionment aids the generation, communication and evaluation of ideas.
• People should take an active part in envisionment wherever possible - the process
allows essential feedback from customers and clients.
• Basic techniques include storyboards, different forms of sketch, mood boards, naviga­
tion maps, wireframes and concrete scenarios.
• Prototyping may focus on a vertical or horizontal slice through the system, or cover
the whole system, and may evolve into a final product or be thrown away and

1 You have been asked to develop a website for a local radio station and have
gone to meet the radio station manager and one of their leading DJs. What
envisionment techniques would you use during and after this meeting? Outline
some initial ideas for alternative design concepts.

2 Mood boards are usually constructed out of physical materials, but they can
also be made in software. Using any software application that allows the
inclusion of visual, audio and text components, make a mood board to explore
the following concepts:
(a) a website for seaside holidays targeted at one-parent families
(b) a website for adventure holidays targeted at active, affluent over-sixties.
This can be done as a single-person exercise, but works best as a small group

Chapter 8 • Envisionment

3 (More advanced) W e

argue stro n g ly in th is b o o k fo r stakeh o ld ers to be

in vo lved as c lo se ly as po ssible in th e e n v isio n m e n t process. D e velo p so m e
b u lle t po ints setting o u t a c o u n te r-a rg u m e n t - th a t designers 'kn o w best".

Further reading
Browsing the design section of a good bookshop, you will find numerous books containing
ideas to stimulate creativity - which you find helpful is very much an individual preference.
Equally, the business section will offer a wide range of published material for enhancing the
generation of ideas in group meetings.
R o sso n ,M .-B. an d C a rro ll, J. (2002) U s a b ility E n g in e e rin g . Morgan Kaufmann, San Francisco, CA.
Chapter 6 covers prototyping.
R udd , J „ S te rn , K . an d Ise n see , S. (1 9 9 6 ) Lo w v s. high fid e lity p ro to ty p in g d e b a te .
In te ra c tio n s,

3(1), 76-85. A readable exploration of the issues.

Snyder, C . (2 0 0 3 ) P a p e r P r o to ty p in g : T h e F a st a n d E a s y W a y to D e sig n a n d R e fin e U se r
In te rfa c e s . Morgan Kaufmann, San Francisco, CA. Everything you always wanted to know
about paper prototyping. A great source of ideas and practical tips.

Getting ahead
Beaudouin-Lafon, M. and M ackay, W . (2012) Prototyping Tools and Techniques. In Ja ck o .J.A .

Fundamentals, Evolving Technologies and
Emerging Applications, 3rd edn. CRC Press, Taylor and Francis, Boca Raton. FL.

(ed) T h e H u m a n - C o m p u te r In te ra c tio n H a n d b o o k ,

The accompanying website has links to relevant websites. Go to
w w w .p e a r s o n e d .c o .u k / b e n y o n

Comments on challenges
Challenge 8.1
The sketches and doodles are being used to explore the problem space. The computer simulation is
also being used in this way and so the scale model put into the wind tunnel is an essential part of that
representation. Both the blueprints and the scale model sent to Marketing are being used to commu­
nicate ideas. The blueprints and the scale model are both used for communication, but the blueprints
are inappropriate for communicating with Marketing. Marketing people are interested in the physical
shape of the design, but the model maker requires a more precise description of the designer's ideas
in the form of blueprints. Also notice that the representations must be accurate enough for their pur­
pose, highlighting the important features but ignoring the irrelevant aspects. In the wind tunnel, the
interior design of the car is unimportant, so the scale model takes no account of this.

Challenge 8.2
Many different ideas are possible here. Examples could include a simplified interactive map, a text
listing by category, a montage of clickable images, etc. Remember that what you are doing here is
trying out ideas, so don't spend time adding too much detail or creating a work of art.



Part II • Techniques for designing interactive systems

Challenge 8.3
No specific comments here, but make sure that you have shown the direction of links on the map
where they are important. If there are multiple links to the same target, the map can be simplified
by adding a note such as 'all pages link back to home page' and omitting the links themselves.

Challenge 8.4
It would be a good idea to emphasize how the paper prototype would allow radically different
concepts to be explored - and eliminated - cheaply and quickly, rather than rejecting weak ideas
only when they had been realized in software.

Challenge 8.5
Presumably the idea here is to impress the management with the quality of the design work and to
'get the contract'. The prototype is probably going to be hi-fi with respect to size. Management will
want to see how the ideas work on the small screen of a smartphone. The prototype will also have
to get over the principles of the design effectively. This might be a novel way of interacting - turning
the 'pages' using a pen, for example. Or there might be some special functionality that the designer
wants to get over: a facility to zoom to the next appointment, perhaps. The designer should identify
these key elements that need to be communicated and prototype them using a hi-fi tool such as
Director or Flash. The designer might also take along some paper prototypes of other concepts and
designs in order to get more involvement and feedback on ideas. It is all a matter of judgement
and resources, trying to 'sell' some of the ideas and concepts (so that the contract can be secured)
and exploring others.

Challenge 8.6

Can gather good feedback from users when there is still plenty of time to modify the design


Fosters a sense of user involvement


Can provide a realistic impression of the end-product


May be possible to develop the prototype into the final product.


May have distracting usability problems
Developers may be reluctant to discard software to accommodate redesigns
Can inhibit some more technophobic users


Can appear too 'finished' to generate comment.

You will probably have thought of others.

Chapter 9




A s w e said in C h a p te r 2, d esig n is m essy . D esig n p ro b le m s a re u su a lly

Introduction 188

9.2 Conceptual design 188

p o o rly fo rm e d a n d c o n tin u e to e v o lv e as s o lu tio n s a re su g g ested . T h is

9.3 M etaphors in design 191

re su lts in m o re id eas, m o re p ro b le m s a n d m o re s o lu tio n s. In d esig n w e

9.4 Conceptual design using

d istin g u ish c o n c e p tu a l d esig n - d esig n in th e a b s tra c t - fro m p h y sic a l

scenarios 196

d e sig n - w h e re id e as a re m a d e c o n c re te . O u r a im in th is c h a p te r is to

9.5 Physical design 202

p ro v id e m e th o d s a n d te c h n iq u e s to h e lp d e sig n e rs d e al w ith desig n

9.6 Designing interactions 206

s itu a tio n s.

Sum m ary and key points 211

T h is c h a p te r a ssu m e s th a t y o u k n o w a b o u t te c h n iq u e s fo r

Exercises 212

u n d e rs ta n d in g an d e n v is io n in g id e as (C h a p te rs 7 a n d 8). It a ssu m e s

Further reading 212

th a t y o u k n o w a b o u t s c e n a rio -b a s e d d e sig n (C h a p te r 3), a b o u t

W eb links 212

d e v e lo p in g p e rs o n a s (C h a p te r 3) an d P A C T a n a ly sis (C h a p t e r 2)

Com m ents on challenges 213

an d th a t th e a im o f d esig n is to a c h ie v e a high d e g re e o f u sa b ility
(C h a p te r 4 ) an d to c re a te e n g a g in g e x p e rie n c e s (C h a p te r 5). T h is
c h a p te r is c o n c e rn e d w ith a m o re a b s tra c t v ie w o f d esig n a n d w ith
th in k in g c o n c e p tu a lly a n d m e ta p h o ric a lly a b o u t y o u r d e sig n . It also
p ro v id e s s o m e m o re fo rm a l w a y s o f c a p tu rin g an d re p re s e n tin g
d esig n s.
A fte r s tu d y in g th is c h a p te r y o u sh o u ld be a b le to :

U n d e rs ta n d th e n a tu re o f c o n c e p tu a l a n d p h y sic a l d esig n


U n d e rs ta n d h o w m e ta p h o r w o rk s in desig n


U n d e rta k e an o b je c t- a c tio n a n a ly sis to in fo rm desig n a n d to
p ro d u c e a c o n c e p tu a l m o d e l o f a n e w syste m


D e s c rib e h o w th e syste m w ill lo o k a n d b e h a v e th ro u g h s p e c ify in g
th e d esig n lan g u a g e a n d in te ra c tio n p a tte rn s


S p e c ify a d esig n in a fo rm th a t ca n b e im p le m e n te d by
p ro g ra m m e rs u sin g use ca se s.


Part II • Techniques for designing interactive systems

9.1 Introduction
Figure 9.1 is the lower part of Figure 3.12, which we used earlier to illustrate the whole
of the design process. It shows the processes of conceptual and physical design (pro­
cesses represented as clouds) and the products of design that are produced at this stage
(represented as boxes). The minimum system specification is a conceptual model, a set
of use cases and a design language. Conceptual design is concerned with arriving at an
abstract description of the system - its logic, functions, structure and content - but not
with how the structure and functions are to be physically realized. Physical design is
concerned with who does what (with the allocation of functions between people and
artefacts), how the artefacts will look and how they behave.

Figure 9.1 Conceptual and physical design

The distinction between conceptual and physical design does not dictate that con­
ceptual design should be finished before physical design starts. Analysts and designers
will iterate between these two levels of design description and will fix on some physical
design decisions in order to understand the conceptual level better. A good deal of early
physical design happens during the envisionment process. This iteration will involve
various kinds of evaluation with people so that we can check that the design really does
meet their needs. The advantage of designing at the conceptual level before details of
the physical design are fixed, however, is that it avoids the problem of ‘design fixation’
and maintains a wide design space in which alternatives can be considered for as long
as possible.

9.2 Conceptual design

<- Mental models were
introduced in Chapter 2

Clear conceptual design is central to developing systems that are understandable.
Designers need to ensure that their conception of the system is easily learnt by people
and fits with their expectations and preferences. This is so that people can develop a
clear ‘mental model’ of the system.
For example, in any GUI application most of us would expect to find a menu that
allows us to open files, close files and create new files. Moreover, we might expect it
to be called ‘File’. Logically we would expect to find these functions grouped together

Chapter 9


somewhere, and if the designer has understood and applied sensible design principles
(Chapter 4) then this should be the case. But often we have to spend a long time look­
ing for some function, or we do not know about the existence of some function, because
the designer has put it somewhere unexpected. The lack of standards for the menus of
mobile phones, for example, results in the need to search the whole structure for an
expected command.
A good conceptual model will come from considering the underlying metaphor that
is being used to provide the structure for the design (Section 9.3), and by considering
how things are classified and organized. Techniques such as card sorting (Chapter 7)
will help to get a good classification scheme in place and to develop a clear ontology.
The object-action analysis described in Section 9.4 is another good technique for this.
A vital part of design work is to explore the design space in the abstract - to think
about what the design is trying to be. Sometimes this will be quite straightforward. If
the system is a website, people will expect it to be like other websites, but for the inno­
vative applications and systems now appearing on platforms such as the iPhone or in
ubiquitous computing environments this is not the case.

Exploring design concepts
Bill Verplank (Verplank, 2007) is an interaction designer who has been sketching and
designing for many years. He argues that interaction design is ‘design for human use’
and focuses on three main things, which he characterizes as:
• How do you do?
• How do you feel?
• How do you know?
How do you do?
‘How do you do?’ is concerned with the ways in which we affect the world. Do you poke
it, manipulate it, sit on it? For example, one distinction he highlights is between handles
and buttons. Handles are better for continuous control (e.g. a trombone), but buttons
are better for discrete control (e.g. a piano keyboard). Handles leave you in control (e.g.
opening a car door) whereas buttons are more likely to trigger something automatic
(e.g. opening an elevator door).
How do you feel?
‘How do you feel?’ concerns how we make sense of the world and the sensory qualities
that shape media. One distinction is Marshall McLuhan’s ‘hot’ versus ‘cool’. Marshall
McLuhan wrote Understanding Media in 1964 and is famed for coining the phrases
‘global village’, ‘age of information’ and ‘the medium is the message’. The book, which
was reprinted in 1994, is a whirlwind tour through the media of his time and has much
insight into how media would develop in our time. He introduced a distinction between
‘hot media’ which are more authoritative and exact and ‘cool media’ which are fuzzy
and incomplete. Cool media invite more participation; they require the audience to fill
in the gaps, to interpret. Hot media extend a single sense in high definition; they are
filled with data. Photography is a hot medium because it is high-fidelity, whereas a car­
toon is a cool, low-definition medium where we fill in the gaps. McLuhan’s book is a
fascinating if difficult read and he extends the ideas of hot and cool to all manner of
concepts such as an axe (hot), the ‘city slicker’ (hot), rural life (cool). Focusing on ‘how
do you feel’ takes us into the areas of satisfaction, affect, enjoyment, involvement and
engagement. In his introduction to the 1994 MIT Press edition of Understanding Media,
Lewis Lapham characterizes McLuhan’s ideas as illustrated in Table 9.1. Do not worry

Chap ter 22 discusses
affect and em otion



Part II • Techniques for designing interactive systems

Table 9.1 Leitmotifs from McLuhan's Understanding Media

Electronic media




















Pattern recognition








Group therapy

Typographic man

Graphic man

Source: Lapham (1994) in McLuhan, Marshall, Understanding Media: The Extensions of Man, Table 1 from Introduction,
© 1994 Massachusetts Institute of Technology, by permission of The MIT Press

too much about understanding these dichotomies; use them as ways of thinking about
‘how do you feel’.
How do you know?
‘How do you know?’ concerns the ways that people learn and plan; how designers want
people to think about their system. For example, Verplank suggests that one choice is
between maps and paths. Paths are good for beginners as they provide step-by-step
instructions on what to do. Maps are good for understanding alternatives. They take
longer to learn but are more robust and are good for expert skill. Maps offer the chance
to take shortcuts. Very often, of course, a given system or product will have to accom­
modate both.

Challenge 9.1
What characteristics do you feel belong to the text message as a medium? Be creative!

Exploring the design space
Design can be thought about through the concept of a design space. A design space
constrains a design in some dimensions whilst allowing exploration of alternatives
in others (Beaudouin-Lafon and Mackay, 2012). Designers always work within con­
straints, whether these are financial or functional, but they need to take care not to

Chapter 9

impose too many constraints too early in the process. This is when they can ignore ideas
for designs because of design fixation - settling on a design idea or a design constraint
that prevents them from exploring possible alternatives. Brainstorming is a good way
of expanding the design space. When writing, thinking about or using scenarios, issues
will arise about design features. This is particularly so when reviewing scenarios and
other design envisionment with clients. It is vital to do this. Very often it is only when
people see some sort of concrete representation of the new system and how it will fit (or
not) with their lives that they are able to comment meaningfully. Issues may concern
the current state of affairs or a future designed position. We have seen how these issues
can be highlighted through adding endnotes to the scenario descriptions, and notes can
also be appended to storyboards and so on. In many cases it will be necessary to revisit
the requirements, which in turn may entail further analysis of the current situation.
John Carroll (e.g. Carroll, 2000) points out that in design work there are often trade­
offs to consider and a design feature may lead to both positive and negative outcomes.
He recommends listing positive and negative features of a design alongside a feature,
as ‘claims’. We have found it useful to identify neutral design features too. Claims are
concerned with explaining the design rationale - why design decisions were taken.
One way of highlighting design issues is to undertake a walkthrough using the concrete
scenarios to drive the thinking of the designer. Scenarios are very effective at forcing
issues into the open, so that claims about designs can be articulated, documented and
In Chapter 3 we introduced the MP3 scenario for the HIC case study. In paragraph P4
and endnotes 8 and 9, a key design decision was how search results should be displayed
and selected. Just one of the many decisions associated with this activity is the size of
the font used to display artists’ names and track titles. The MP3 domain demands that
quite a lot of text is displayed so that people can make a selection. So font size is a key
design issue.
Some of the positive and negative features of using a large font size are:
• It can be seen from further away (positive).
• It takes up valuable screen space (negative).
• It means fewer tracks can be displayed (negative).
There are many variations of techniques that can be used to focus attention on design
issues. Listing the actions that people will have to take in order to accomplish a goal
using a specific design and identifying the positive and negative aspects of a prototype
is one way. Another is to list the options against the design criteria, the QOC technique
described in Chapter 3.
Warr and O’Neil (2007) describe the envisionment and discovery collaboratory
(EDC) that aims to support social creativity and collaborative design through the use
of shared ‘boundary objects’ (Figure 9.2). Boundary objects (or representations) ‘talk
back’ to the design team through the externalization of stakeholders’ concepts.

9.3 Metaphors in design
Metaphor is generally seen as taking concepts from one domain (called the source
domain, or the vehicle) and applying them to another (the target, or tenor). Recall
your schooldays and how you studied ‘The ship ploughed through the waves’, or ‘The
President marshalled his arguments to defend his position’. The first of these likens a
ship moving through the sea to a plough moving through a field. It suggests the waves




Part II • Techniques for designing interactive systems

Figure 9.2 The EDC
(Source: Warr, A. and O'Neill, E. (2007) Tool support for creativity using externalizations, Proceedings of the Sixth
ACMSIGCHI Conference onCreativityandAMP: Cognition, Washington, DC, 13-15 June, C&G '07, ACM, New York,
pp. 127-36. © 2007 ACM, Inc. Reprinted by permission,

See Chapter 25
on navigation

are like the furrows. It has connotations of strength and how the ship is pushing aside the
sea. For some people it connotes speed of movement. In the second we see arguments
likened to a battle, arguments being marshalled as if they were soldiers, the President’s
position being analogous to a castle or other physical place that needs defending.
In the development of interactive systems we are constantly trying to describe a
new domain (a new application, a different design, new interactive facilities) to peo­
ple. So we have to use metaphor to describe this new domain in terms of something
that is more familiar. Blackwell (2006) gives a comprehensive treatment of the role of
metaphor in interactive systems design. After a while the metaphorical use of a term
becomes entrenched in the language to such an extent that people forget it ever was a
Paths and maps may be thought of as metaphors for the design of interactions.
Different metaphors will lead to different conceptions and designs. Think of the idea
of navigating an interactive system, for example. Many people immediately think that
navigation is trying to get somewhere specific, but this is only one view (often called
‘wayfinding’). We also browse around and explore. If we think of navigation as in a city
then we think of roads and signposts, metros that take us invisibly from one part of the
space to another, taxis to transport us, or buses that we have to learn about.
Considering one metaphor can stimulate creative leaps into other ways of thinking.
For example, during a collaborative design meeting to look at the HIC interface as a
‘Rolodex’ (Figure 9.3), a manual card index device that allowed people to rapidly flip
through standard-sized cards, a ‘gun barrel’ design emerged (illustrated in the left-hand
part of Figure 9.4). Although the gun barrel idea was rejected, the Rolodex concept
seemed to capture the idea of searching and retrieving results with an intuitive naviga­
tional style of flicking through the ‘cards’. In this case the conceptual metaphor of the
Rolodex translated nicely into a visual representation. So here an interface metaphor
seemed wholly appropriate and indeed was implemented as part of the first functional

Chapter 9

A t^ ih a-b cix c



F ig u r e 9 .3 Sketch of a Rolodex
interface metaphor in HIC project


(Rolodex is a registered trade name, but we
use the term in this book to indicate the
concept rather than the product)

Information Visualisation Design IV

Information Visualisation Design I

There were 25 results found





Search Result 7
Search Result 8
Search Result 9
Search Result 10
Search Result 11


There were 25 results found

F ig u r e 9 .4

Snapshots of alternative designs for searching the HIC

Navigation metaphors
Metaphors that might be useful for thinking about navigation have different associa­
tions. A wilderness, for example, is frightening, confusing, enchanting. A desert is intim­
idating and beautiful but has no landmarks. Such metaphors might encourage forging a
path, enjoying the scenery and getting out. Wilderness and desert can be included in an
overall landscape metaphor where different types of terrain represent different types of
information. These metaphors encourage exploration by the user; the system provides
a high-level metaphor, but users provide the more detailed structure themselves.
The night sky offers a different sort of space. To the human eye, it contains objects,
clusters and patterns and it is very big. It supports the activities of mapping and identi­
fying objects. However, there are relatively few types of object in the night sky (galaxies,
stars, planets). It is the configurations and subtypes of these objects that are of interest.
Science fiction concepts such as warp drives and worm holes can be used for quick




Part II • Techniques for designing interactive systems

and magic transportation to distant parts of space. The open sea is another metaphor.
It encourages a distinction between surface and depth. Thus it is natural to think o f a
lot o f inform ation as being hidden beneath the surface and only available fo r view ing
if the user dives dow n. Currents can link continents and islands and take people to
unexpected places. People can look fo r islands o f inform ation; archipelagos provide
clusters. A m useum has been structured to allo w free roam ing, yet is also structured to
facilitate learning. A library is suitable fo r finding specific inform ation. It is w ell organ­
ized and structured.
These m etaphors are not m eant to suggest that the interface to a particular prod­
uct looks like a desert, wilderness or library (though sometim es such explicit interface
m etaphors can be useful); the idea here is to think about activities in different ways.

Challenge 9.2
C o n s id e r s o m e o f th e fa m ilia r c o m p u tin g c o n c e p ts : 'w in d o w s', 'cu t a n d p a ste ', 'b o o tstra p ',
'o p e n ' a 'fo ld e r', ‘c lo s e 1a 'file '. M a k e a lis t o f th e s e m e ta p h o rs . T ry to w rite d o w n w h e re
th e y c a m e fro m .

Metaphor is not just a literary thing, it is fundamental to the way we think. Lakoff and
Johnson (1981, 1999) and their colleagues have worked on their theories of metaphor
for over 20 years. They describe a philosophy of ‘experientialism’ or cognitive seman­
tics. They argue that all our thinking starts from the metaphorical use of a few basic con­
cepts, or ‘image schemas’, such as containers, links and paths. A container has an inside
and an outside and you can put things in and take things out. This is such a fundamental
concept that it is the basis of the way that we conceptualize the world. A path goes from
a source to a destination. The key to experientialism is that these basic concepts are
grounded in spatial experiences. There are other basic ‘image schemas’ such as frontback, up-down and centre-periphery from which ideas flow.
An important contribution from this view is that a metaphor is much more than a
simple mapping from one domain to another. It is a much more complex affair. Take the
idea of a window as it appears in a computer operating system. We know a computer
window is different from a window in a house. It shares the idea of looking into a docu­
ment, as you might look into a house, but when you open it, it does not let the fresh air
in. It is only ever a window into, or onto, something. Moreover, it has a scroll bar, which
a window in a house does not. In a similar fashion we know that the trash can, or the
recycling bin, on a computer screen is not a real trash can. The connotations of recycling
files are really quite complex.
The contribution that Fauconnier and others have made (e.g. Fauconnier and Turner,
2002) is to point out that what we call ‘metaphors’ in design are really blends. A blend
takes input from at least two spaces, the characteristics of the domain described by the
source and the characteristics of the target that we are applying it to. So a computer
window takes elements from the domain of house windows and elements of the func­
tioning of a computer trying to get a lot of data onto a limited screen display. The meta­
phor of a folder is a blend from the domain of real folders that you keep papers in and
the domain of computer files which have a physical location on a disk.
Figure 9.5 illustrates this idea of a blend. The blend that results from bringing two
domains together in this way will have some features that were not in the original domains.

Chapter 9

Blends have an emergent structure that results from bringing two sets of concepts (from
the source and target domains) together. So, the computer window has different features
from both a real window and the computer commands that preceded it. The Rolodex con­
cept that arose during the HIC case study (Chapter 6) had emergent properties. These con­
cerned how people could navigate in the Virtual’ Rolodex (as opposed to a real, physical
one) and how the search results were presented as opposed to how they were presented
following a traditional query. It is exacdy these emergent properties that make one design
better than another.
For metaphors and blends to work, there must be some correspondences between
the domains that come from a more generic, or abstract, space. So, for example, the
metaphor ‘the ship ploughs through the waves’ works, but the metaphor ‘the ship ran
through the forest’ does not. In the second of these there is not sufficient correspond­
ence between the concepts in the two domains. Of course, the generic space is itself a
domain and hence may itself be using metaphorical concepts. This process works its
way back until we reach the fundamental image schemas that are core to our thinking.
These include the container, path, link and others such as colours (red is hot, blue is
cool, red is stop, green is go) and those bodily schemas that come from experience and
perception (up, down, in, out, central, peripheral, etc.).
Thinking figuratively is fundamental to both the design and use of computer systems.
One job of the interaction designer is to come up with a good metaphor that will help
people in learning and using the system and in understanding the content. Metaphor
design works as follows:
• The source domain has some features (concepts and functions).
• The target domain has some concepts and features.




Part II • Techniques for designing interactive systems


So it is important to analyse the relationship between these.
Too many features in the base domain results in ‘conceptual baggage’of the metaphor.
Too few features, or too many inappropriate features, may lead to confusion.
Aim for people deriving appropriate expectations.

Note that metaphor design does not imply a physical resemblance. The important thing
about metaphor is to get a good conceptual correspondence. Sometimes it is appropri­
ate to carry through a conceptual metaphor to a physical metaphor, but not always. As
with any aspect of interactive system design, evaluation of metaphor is essential. There
are, however, a few principles for good metaphor design:
• Integration. This is to do with coherence and not mixing metaphors. The aim here is
to manipulate the whole blend, maintaining the web of relationships. The blend has
its own structure and it is this that needs to have consistency maintained.
• Unpacking. People should be able to unpack the blend and understand where the
inputs have come from and why they work. Of course, this will often be a case of
interpretation. With consideration, reflection and evaluation the designer can
achieve this. Designers should only have things in the blend for a good reason.
• Topology. The different spaces should have a similar topology. We saw how the struc­
tures of waves and furrows have a similar topology, whereas waves and trees do not.
Topology is about how the concepts are organized and structured.
• Analysis. When undertaking an analysis the designer should concentrate on getting
the appropriate functionality and concepts, exploring the ramifications of the meta­
phor, evaluating how people will interpret it.
• Design. At the design level designers should consider how to represent objects and
actions. They do not have to be realistic visual representations (e.g. names of menu
items are often metaphorical).
Designers cannot avoid metaphors in interaction design, so they need to consider them
explicitly. Metaphors are really blends between two or more input spaces and have their
own emergent structure. Using metaphors that exploit the fundamental domains such
as bodily and perceptual schemas may help people to understand them and to form an
accurate mental model. Designers should consider principles of good blends. Imaz and
Benyon (2005) develop these ideas as ‘designing with blends’.

Challenge 9.3
T h in k o f th re e d iffe r e n t m e t a p h o rs ( o r w a y s o f th in k in g a b o u t) th a t c o u ld be u se d f o r a
d ia r y fu n c t io n o n a ta b le t.







............................................. -

' ""


.........- ....................

' ....................



9.4 Conceptual design using scenarios
In Chapter 3 we illustrated how scenarios can be used throughout the design process.
Stories aid understanding, conceptual scenarios abstract from stories to provide generic
activities. Fixing certain design constraints leads to concrete scenarios that may finish
up as functional specifications expressed as use cases. A scenario corpus is developed
that should be discussed and evaluated at design team sessions and with the participa­
tion of stakeholders. There are degrees of concreteness in scenarios. The most concrete

Chapter 9 • Design

forms are used to envision or evaluate specific interactions. While they are superficially
easy to construct, there are a number of ways in which scenarios can be made more
• Complement the scenarios with some of the more visual envisioning techniques.
• In a large design team, include real data and materials so that people not directly
involved can appreciate concrete details.
• Think hard about underlying assumptions.
• Include good characterization and develop a number of personas. If this is done well,
members of the team start talking about the characters - ‘If you design it like that,
what will happen when the grandmother tries to use it?’
• Provide a rich contextual background - this grounds design decisions in real life,
forcing the designer to think about practicality and acceptability.
• Team members can write their own concrete version of a conceptual scenario that
reflects their particular concerns. These can be brought together and overlaps
The aim is to come up with a collection of scenarios that covers all the major uses and
functionality of the product. It would be impossible to write scenarios for all possible
variations in use, but those produced should cover:

Interactions that are typical of a number of similar use situations
Design issues that are particularly important for the focus of the project
Areas where requirements are unclear
Any aspects that are safety-critical.

A good way of doing conceptual design is to undertake an object-action analysis of the
scenario corpus. For each of the scenarios in the corpus the analyst works through
the scenario descriptions, identifying the various objects that are mentioned and the
various actions that are performed. Objects are often indicated by nouns or noun
phrases and activities and actions by verbs.

Challenge 9.4
L o o k th ro u g h th e fo llo w in g p a ra g r a p h fr o m th e E d in b u rg h F e stiv a l s c e n a r io (d e s c rib e d
in d e ta il in C h a p t e r 6 ). Ig n o rin g c o m m o n v e rb s s u c h a s 'w a s', 'is', e tc . a n d ig n o rin g
d u p lic a t e s , lis t th e m a in n o u n s a n d v e rb s a n d h e n c e t h e m a in o b je c ts a n d a c tio n s.

The Edinburgh Festival is a large arts festival that takes place in the city for three
weeks in August. It consists of two arts festivals - the Edinburgh International
Festival and the Edinburgh Festival Fringe - a book festival, a film festival, a jazz
festival and a variety of related events. The International Festival is the original, and
up until the mid-1980s was the bigger of the two. This is the official festival, which
features prestigious performers from around the world, world-class orchestras,
composers, ballet troupes, etc. The Fringe, on the other hand, started as an unof­
ficial adjunct to the festival, traditionally more informal, and adventurous. It fea­
tured new theatres like the Traverse, or the work of artistic mavericks like Demarco.
Gradually over the years it has become larger than the official International Festival.
In total the Edinburgh Festival consists of some 1200 distinct events that take place
at 150 different venues spread throughout the city.




Part II

Techniques for designing interactive systems

Working with a corpus of scenarios in this way requires four stages:
1 Analyse the individual scenarios, distinguishing between specific actions and more
general, higher-level activities.
2 Summarize objects and actions from each scenario, merging similar or identical
actions where necessary.
3 Bring together the analyses from the individual scenarios, collating them into sum­
marized objects, actions and more generic activities.
4 Merge actions and objects where they are identical and give them a single name.

Objects and actions in MP3 example

MP3/01 is
3, Section 3.4

« - Scenario
in Chapter

Table 9.2 shows how part of Scenario MP3/01 - ‘How does that song go again?’ - is
analysed. Activities are shown in the far left column referencing the paragraph number.
Where these appeared to be made up of a sequence of individual sub-activities, these
are identified in column 2. Actions and objects derived from these appear in columns 3
and 4. Comments are included in column 5. Of course, this is only a fraction of the analysis of the MP3/01 scenario analysis used here to illustrate the idea.
Table 9.3 shows a portion of the collated results across all the scenarios. A tally of the
number of occurrences of each action (column 1) and object (column 2) is kept. Various
notations are used to indicate questions, slightly different views or uses of the terms and
so on. The aim of this analysis is to understand the objects and actions in a domain. It is
vital to note that there is no definitive or ‘right’ answer here. The object-action analysis
is just another way of exploring the design space.
Actions that could be thought of as generically similar can now be grouped together,
prior to the final distillation stage. This requires careful attention, to avoid mistakenly

Table 9.2 Object-action analysis of part of scenario MP3/01

Consists of




S e a rch fo r M P3

Go to Search
function P3

Go to

Search object

'Search object1may need revision?

Enter query (track
name) P3

Enter (user input)

Search object

Select search result
(MP3 track) P4


Search result (track)

= MP3 track. There
is no 'browse search
result1formula here,
as it is specified
that search result
contains only one
object (track)

Play track P4

Play (start play)


'Play' does not
imply playing
complete track track may be
paused, stopped,
fast-forwarded, etc.
'Start Play" may be
the better term

t ra c k b y n a m e P3

P la y t ra c k P4

Chapter 9 • Design

Table 9.3 Portion of consolidation of objects and actions in MP3 domain with number
of occurrences in parentheses
Scenarios MP3/01 to MP3/05: activities and objects decomposition - stage 3 (A) (all
actions and objects collated)
All actions

All objects

Go to (21)

Playlist (30)

[Go to] (1)

Playlist catalogue (2)

Load (1)

Playlist catalogue (7)

Modify (4)

Query (4)

Move (1)

Search object (9)

(Move) (1)

Search result (Track) (1)

Name (2)

Search result (3)

Name (user input) (4)

Set up (1) [scenario MP3/03]

Open (3)

Track (32)


Track (MP3 file) (1)

Play (start play) (7)

Track list (1)

Repeat (replay) (1)


Re-save (save) (1)

Tracks (MP3 files) (1)

Save (8)

Tracks list (9)

[Select] (1)

[Tracks list] (2)

Select (specify) (1)
[Select (specify)] (3)

merging together slightly different actions. The guiding principle is to look for concep­
tual or functional parallels among the actions, indicating likely candidates for grouping.
The table is annotated with comments, documenting the criteria applied in making the
groupings. Here, each grouping of actions is merged and given a single name. In each
case this is the generic term that will be used from this point on. Table 9.4 illustrates this
process with the actions of ‘select’ and ‘choose’.
So, the object-action analysis has resulted in a generic action of select and an under­
standing of the various objects that can be selected: Track, Playlist, Playlist Catalogue,
Query result.

Diagrammatic techniques
The result of the object analysis could be represented as an object model, or entityrelationship model as illustrated in Figure 9.6. This may be read as a Playlist Catalogue
consisting of many Playlists, though each Playlist is on just one Playlist Catalogue.
A Playlist consists of many tracks. Each track is on just one Playlist and one Tracklist.




Techniques for designing interactive systems

Table 9.4 Considering the various uses of actions select and choose
[Select] (1)

7 'Select1, ‘(specify)', 'Choose' all describe a user's action of

Select (specify) (1)

• selecting an item or group of items from a list or other
display object

[Select (specify)] (3)

• selecting an option from a menu of other actions.
Here, the HIC has determined the list of possible options/
interactions available to the user, and is presenting it to
the user (in a number of possible forms and modalities).

Choose (1)


Choose (specify) (1)










Figure 9.6 Possible conceptual model for MP3 example

A Track may be the result of a Query. Notice how, by developing a conceptual model, we
are able to raise and discuss design issues. You may disagree with some of the assertions
above. This is fine. This is exactly why making the conceptual model explicit is useful.
Designers will often represent the conceptual model of a system using a diagrammatic
technique such as an entity-relationship model or object model. Object models, or entityrelationship models, represent the main objects of interest in a domain and the relation­
ships between them. There are many books devoted to such conceptual models, and the
techniques can be used to explore the conceptual structure, not simply to document it.
There is an important distinction in conceptual models between the specific instances of
an object and the class or type of object. In the MP3 example, an instance of the object
type ‘Track’ might be ‘Moondance’ and another instance might be ‘Gloria’ (both songs by
Van Morrison as it happens). What makes us group these things together as an object type
called Track is that they have certain characteristics in common such as a track name, a
duration and so on (classification is discussed briefly in Chapter 7, also see discussion in
Chapter 3). Relationships between objects are expressed in terms of how many instances
of an object can be related to how many instances of another object. Typically we are
not interested in exactly how many instances, but rather whether a relationship exists
between one or many instances. The conceptual model is annotated with a 1 if an instance
can be related to only one other instance or an m if it can be related to many.

Chapter 9


Figure 9.7 shows two alternative conceptual models of the same thing, an ATM. In
the upper part is an object model that shows the relationships between the concepts
person, card, account and ATM. A person may ask about an account, the card is inserted
into the ATM and so on. In the lower part is an entity-relationship model. This is more
complex, but captures more of the semantics of the situation. The model distinguishes
between the concept of a user and the owner of the card. It distinguishes a usage of the
ATM and the accounts that may be accessed.
Such diagrams rarely exist w ithout some further explanation, and entityrelationship diagrams in particular can become quite formalized. For example, the
entity-relationship diagram in Figure 9.7 includes a notation showing the participa­
tion conditions (optional or mandatory) of entities in relationships and some out­
line definitions of the entities in terms of the attributes that they contain. Attributes
can be shown on the diagram as ovals if required. It is not the intention to explore
all the details of conceptual modelling techniques here, but rather to make designers
aware that they exist. Books are available on object modelling (e.g. van Harmelen,
2001) and on entity-relationship modelling for interface design (Benyon et a l, 1999).
Some approaches to information architecture also include formal models. The point to
note is that such techniques can be very useful in externalizing the conceptual struc­
ture that underlies a design.
In website design it is usual to produce a ‘site map’ - a conceptual model of the site’s
structure. Conceptual modelling using a formalism such as an object model can be a

Entity definitions outline
User (Card. PIN)
Owner (Name, Address...
ATM (ATMnumber, address...
Use (Card, PIN, ATMnumber, Amountwithdrawn...
Account (Accountnumber...
Accesses (Card, PIN, ATMnumber, Accountnumber...

Figure 9.7 Two conceptual models of an ATM: object model above and entity-relationship below


Part II • Techniques for designing interactive systems
-> Information
architecture and web­
site design are cov­
ered in Chapter 14

very powerful tool in helping the designer to think about the details of a design. By
externalizing the objects and relationships in a system the designer can see more clearly
whether the logic of a design works.

Elements of interaction
Dan Saffer (2009) suggests that there are six key elements of interaction design that
need to be considered. In many ways these are similar to the notion of interaction tra­
jectories discussed in Chapter 5. His elements are:
• Motion - objects that don't move don't interact. Motion as a trigger for action.
Behaviour as motion coloured by attitude, culture, personality and context.
• Space - movement happens in space, interaction design involves a combination of
physical and digital space.
• Time - movement through space takes time and all interactions take place over time.
Time creates rhythm.
• Appearance - proportion, structure, size, shape, weight, colour.
• Texture - variables such as vibration, rough, smooth, etc.
• Sound - pitch, volume, timbre.






9.5 Physical design

L________________________________________ I ________________________________________________________________________________A

As we discussed in Chapter 3, physical design is concerned with how things are going to
work and with detailing the look and feel of the product. Physical design is about structur­
ing interactions into logical sequences and about clarifying and presenting the allocation
of functions and knowledge between people and devices. Physical design is concerned
with taking this abstract representation and translating it into concrete designs.
There are three components to physical design:
• Operational design is concerned with specifying how everything works and how con­
tent is structured and stored.
• Representational design is concerned with fixing on colours, shapes, sizes and infor­
mation layout. It is concerned with style and aesthetics.
• Interaction design in this context is concerned with the allocation of functions to
humans or to technology and with the structuring and sequencing of the interactions.
Much of the detail of physical design is covered in the chapter on the visual aspects of
interface design (Chapter 12). In this section we consider two key design ideas that help
designers deal with operational design and interaction design: design languages and
interaction patterns.

Skeumorphic design
Skeuomorphic design is designing something to physically resemble something from
the past. This may work quite well if it helps people transfer the functionality from a
familiar object to a new one and a skeuomorphic design may utilize an explicit visual

........-............................................... ......... .....-......

-... - ---- ------- I

Chapter 9

metaphor in order to build on a conceptual metaphor. But often the use of a skeuomorphic design seems gratuitous, unnecessary and an out-of-date aesthetic. Apple
have come in for a lot of criticism in the Lion operating systems for making the place
holder for electronic magazines look like an old-fashioned wooden bookshelf and for
making the calendar look like an old leather calendar.
One critic, James Higgis, complains that he finds the skeuomorphic designs from
Apple patronizing, particularly compared to the streamlined look of the Metro inter­
face (see Box 9.4 and Figure 9.9, p. 204). However, Apple do promote skeuomorphic
design in their user experience guidelines, saying 'On iPhone, people instantly know
what the Voice Memos app does, and how to use it, because it presents a beautifully
rendered focal image (the microphone) and realistic controls'. (See Figure 9.8.)

Figure 9.8 Voice recorder

from Apple
(Source: Mandy Cheng/AFP/
Getty Images)

Design languages
A design language consists of the following:
• A set of design elements such as the use of colour, styles and types of buttons, sliders
and other widgets
• Some principles of composition (i.e. the rules for putting them together)
• Collections of qualifying situations - contexts and how they affect the rules.
A consistent design language means that people need only learn a limited number of
design elements and then they can cope with a large variety of different situations.
A design language is how designers build meaning into objects, enabling people
to understand what things do and to make distinctions between different types of
Any language provides a way of expressing things, and design languages are ways of
expressing design concepts. Languages are useful for particular purposes if they have
appropriate elements and appropriate organizing principles and use an appropriate
medium for both expression and transmission.




Part II

• Techniques for designing interactive systems
Rheinfrank and Evenson (1996) stress that design languages have most impact
when they have become deeply embedded and when people use them and exploit them
unconsciously. Their method for design includes developing a design language through:
• Characterization - the process of describing existing assumptions and any pre­
existing design languages
• Re-registration - the creation of a new assumption set through exploring trends and
needs through field research
• Development and demonstration - using storyboards, prototypes and other envision­
ing techniques
• Evaluation of the reactions to the design
• Evolution of the language over time. No matter how good a design, it will only last so
long - until circumstances force it to be revisited.

Microsoft’s design language
Starting with the Windows 7 mobile platform and moving onto the desktop in
Windows 8, Microsoft have introduced a new design language for their products.
The inspiration for the language is described on their website as being Swiss influenced
print and packaging and Microsoft software such as Zune and Office Labs, plus games
that focus on motion and content over chrome.
The main features of the design language are:
• Motion. A system is created to bring the interface to life by developing a consist­
ent set of motions or animations which provide context for usability.
• Typography. Aiming for the right balance of weight and positioning can help lead
users to more content.
• C o n t e n t n o t C h r o m e . Extra chrome is removed so that in the U l, the main focus
becomes the content.
• Honesty. Design specifically for a hand-held device, incorporating a high resolu­
tion screen and using touch. Interaction is expedited and made simple.


Figure 9.9 Microsoft's user interface


Chapter 9 • Design

Design languages help to ensure transparency, helping people to understand what is
going on inside a device. They also afford transferability of knowledge from one device
to another. The user of one Nokia phone can generally expect to find similar design on
another Nokia phone. This also means that people will more readily see opportunities
to use a device or function and will expect certain behaviours, structures or functions.
Finally, people will identify with a style, which helps to define their identity; they act
through the design language.

Design language for the MP3
The MP3 application would have to fit in with the overall design language of the HIC,
but could also have its own features. The key aspect of the HIC’s design language was
the Rolodex for displaying and accessing search results and the object, action and cat­
egory bars. In previous work on the HIC, the problem of how to select text items from a
Rolodex list had not been considered in depth. This was a significant issue, particularly
in a touchscreen environment where serious functional constraints were imposed by
the size and proximity of text in the display. Selecting by simple touch was probably the
most intuitive solution. However, all but the smallest fingers would find it hard to pick a
track unambiguously unless the text was large and widely spaced. One possible solution
that was proposed is shown in Figure 9.10.
People can drag the track into the white slot in the module (A) to select it. In this
instance, the interaction can take two possible courses: people either drag the track
into the slot and take their finger away, resulting in the track being loaded; or they can
abort the selection, in which case the track returns automatically to its position in the
Rolodex. This ‘recoverability factor’ is one of the basic design principles.
Whether the interaction is completed or aborted, the text item changes colour from
black (B) to orange (C) while it is in transit, to indicate it is ‘active’. A dimmed version
of the track name (D) remains in the Rolodex while the track is being dragged. Thus the
proposed language elements are dimming of selected items, dragging to select, chang­
ing the colour to indicate selection and so on.
An important technique for physical design is the wireframe. Wireframes are used
in website design and in app design and in general are an important construct in infor­
mation design. A wireframe is a skeleton, or outline of the information structure of a
physical design. It defines the major structural elements of different pages in a design.

C h ap ter 4, Section 4.5
discusses design principles

<- W irefram es are
discussed in Chapter 8



Part II • Techniques for designing interactive systems

9.6 Designing interactions
The design of interactions is critical to interactive systems design. The conceptual design
should be as independent of an implementation as possible. The move from conceptual
to physical design requires designers to allocate functions and knowledge to persons or
to devices and hence to create interactions. For example, in the case of the MP3 player
there have to be actions that select tracks and that play tracks, that modify playlists or
that load playlists. But this does not say who does what. For example, the selection of a
track can be left to a random function of the MP3 player. Playlists may be bought from
a content provider, or created by the system based on statistics such as how often they
are played.
In designing interactions - i.e. allocating functions to people or to devices - designers
need to consider the capabilities of people and the constraints on what they can do.
People will forget things over time. They will forget things in working memory in a very
short time. They are not good at following long lists of instructions, at carrying out bor­
ing tasks repeatedly and so on. On the other hand, people are good at improvising and
at dealing with ambiguity and incomplete information. On the whole, the capabilities of
technology are just the reverse.
But it is not just a question of efficiency. The interaction should be engaging, enjoy­
able and fulfilling. Moreover, if the system supports working life, it should help to cre­
ate satisfying and meaningful jobs, while a product for home use has to fit lifestyle and
desired image.
Of course, in a very real sense this whole book is about designing interactions,
so understanding, evaluation and envisioning design ideas are critical. In this sec­
tion we aim to provide more formal methods to help in this process. The first of these
is interaction patterns and the second reviews a number of models for structuring

Interaction patterns
The idea of ‘patterns’ - perceived regularities in an environment - has been adopted by
designers of interactive systems and appears as interaction patterns. As with architec­
tural patterns (see Box 9.5), interaction patterns can be identified at many different lev­
els of abstraction. For example, on most PCs if you double-click on something it opens
it; if you right-click, it displays a menu of operations you can perform. Macintosh com­
puters have only a single mouse button so the ‘right-click’ pattern is unknown to Mac
users (they have control click instead). Most playing devices such as VCRs, DVDs, cas­
sette players and MP3 players on a computer have a play, stop, fast forward and rewind
interaction pattern. Patterns build up into the complex interactions of menus and mice
that we are familiar with: patterns of layout of menus, of the highlighting when the
mouse rolls over an item, flashing when an item is selected and so on. More recently,
people have been developing gesture patterns for interacting with multi-touch displays
(Wobbrock et al., 2009).
General usability patterns have been identified which to a large extent are similar
to design guidelines, but the advantage that patterns have over guidelines is the rich
description and examples that go with them. In the HIC the main interaction pattern
was to select an object on the right-hand bar and then select an activity from the activity
bar (or vice versa). Another pattern was to touch the scroll buttons and the bars would

Chapter 9 • Design

Alexandrian patterns
In architecture Christopher Alexander (Alexander, 1979) has been very influential in
introducing the idea of architectural patterns. These are regular good design ideas.
For example, it is a good idea to have small parking lots in a neighbourhood because
very large parking lots are ugly and disrupt the neighbourhood. It is a good idea to
have pavement cafes in a city where people can sit outside because it creates a nice
atmosphere. It is a good idea to have a low wall next to an open area so people can
sit on it.
Alexander's patterns for architectural features are at different levels of abstraction from patterns for walls to patterns for whole cities. Each pattern expresses a relation
between a certain context, a certain system of 'forces' which occurs repeatedly in that
context (i.e. a particular problem) and a solution which allows these forces to resolve
themselves. Patterns, therefore, refer to other patterns and are part of larger patterns.
For example:
• GALLERY SURROUND proposes that people should be able to walk through a con­
necting zone such as a balcony to feel connected to the outside world.
• OPENING TO THE STREET says that people on a sidewalk should feel connected to
functions inside a building, made possible by direct openings.
Patterns are embodied as concrete prototypes rather than abstract principles and tend
to focus on the interactions between the physical form of the built environment and
the way in which that inhibits or facilitates various sorts of behaviour within it. Pattern
languages are not value-neutral but instead manifest particular values in their names
and more explicitly in their rationales.
Alexander specified over 200 patterns in his book. Pattern 88 (adapted from Erickson,
2003) is shown below. Notice how it refers to other patterns (numbered) and how there
is a wealth of rich, socially based description.

88 Street Cafe
[picture omitted]
. . . neighborhoods are defined by Identifiable Neighborhood (14); their natural
points of focus are given by Activity Nodes (30) and Small Public Squares (61). This
pattern, and the ones which follow it, give the neighborhood and its points of focus,
their identity.
The street cafe provides a unique setting, special to cities: a place where people
can sit lazily, legitimately, be on view, and watch the world go by.
The most humane cities are always full of street cafes. Let us try to understand
the experience which makes these places so attractive. We know that people
enjoy mixing in public, in parks, squares, along promenades and avenues, in street
cafes. The preconditions seem to be: the setting gives you the right to be there,
by custom; there are a few things to do that are part of the scene, almost ritual:
reading the newspaper, strolling, nursing a beer, playing catch; and people feel
safe enough to relax, nod at each other, perhaps even meet. A good cafe terrace
meets these conditions. But it has in addition, special qualities of its own: a person
may sit there for
[nine paragraphs of rationale omitted]
Encourage local cafes to spring up in each neighborhood. Make them intimate
places, with several rooms, open to a busy path, where people can sit with coffee or






Techniques for designing interactive systems

a drink and watch the world go by. Build the front of the cafe so that a set of tables
stretch out of the cafe, right into the street.
[diagram omitted]
Build a wide, substantial opening between the terrace and indoors - OPENING TO
THE STREET (165); make the terrace double as A PLACE TO WAIT (150) for nearby
bus stops and offices; both indoors and on the terrace use a great variety of different
kinds of chairs and tables - DIFFERENT CHAIRS (251); and give the terrace some low
definition at the street edge if it is in danger of being interrupted by street action STAIR SEATS (125), SITTING WALL (243), perhaps a CANVAS ROOF (244).
[text omitted]

Patterns are described in some general format. The format used in the HIC case study
is illustrated in Table 9.5, which shows the interaction pattern for the Edit function in
the MP3 application. Each pattern is described in this standard way, given a name and
description, an indication of the problems it addresses, the design rationale or forces
that act on the design decision, and the solution that has been adopted. Patterns will
typically refer to other patterns and be referenced by other patterns.

Table 9.5 An interaction pattern for the edit action
Interaction pattern: Edit
D e s c r ip t io n

Edit the contents of an HIC entity
(Conceptually associated with 'Sort" - q.v.)

E x a m p le s

Adding MP3 tracks to a playlist
Adding a URL (Web address) to an MP3
Favourites List
Moving tracks to different positions within a playlist
Moving MP3 tracks from one genre list to another
Removing a track from a playlist

S itu a tio n

Some entities - lists and categories, for instance - have constituent objects
associated with them. The user will want to change what these are, and the way
they are organized within the 'umbrella' entity.

P r o b le m

How does the user know which entities are editable and, if so, how to perform
the 'Edit1action on them? How will the user select the components of the entity
which are to be the subject of the edit?
If objects are removed from an entity, will this mean they are permanently
deleted from the HIC?
Is it the 'umbrella object' which is actually edited, or its constituent objects? (For
instance, a list, or its entries?)

F o r c e s (i.e . is s u e s a ffe c tin g
t h e p r o b le m a n d p o s s ib le
s o lu tio n s )

The object(s) to be edited will be displayed on the screen. If the user requires to
move the position of items within an object, or move an item from one object
to another, all the relevant objects will have to be on the screen. The size of the
objects, and of the screen, presents a limitation.

Chapter 9 • Design

Interaction pattern: Edit
Some items may be difficult to isolate (select) on the screen due to their small
size or close proximity to each other, and this may make them difficult to edit for example, text strings in a list.
Alternative modalities could be offered other than screen touch.
Editing may involve more than one step: select > edit >go/confirm.
There should be clear feedback telling the user the changes they are about to
make. There should probably be a means of cancelling or escaping from the

The graphical interface signals to the user (perhaps by means of a familiar or self­
explanatory symbol) whether an entity can be edited. It may also be clear from
the context which items are likely to be editable (for instance, the user would
expect playlists to be editable).
There are several possible means of editing. The user could select items one
by one or in groups, and use a 'Go' action to complete the process (suitable for
touchscreen, remote control or perhaps voice activation). Or she could 'drag and
drop' objects to edit them (suitable for touchscreen). Items being edited could
change their appearance - perhaps change colour.
If the object being edited (such as a list) is larger than the available screen space,
it could be divided into contiguous sections. A suitable device for displaying this
might be the scrolling 'Rolodex1device already established in the present HIC

Resulting situation

It is clear to the user which objects of the HIC can be edited; the interaction
pathways for editing them are apparent (if more than one step is involved, the
sequence should be apparent). Clear feedback is given during the Edit action,
and the screen is updated afterwards to reflect the new situation.


This pattern is conceptually associated with 'Sort1, the important distinguishing
factor being that 'Edit' can change the number and identity of the constituent
objects in an entity, while 'Sort simply rearranges (categorizes) them.
It also has links with 'Delete'. It is unclear at this stage whether removing an MP3
track from, say, a playlist or a track list, actually deletes it from the HIC entirely, or
merely from that list (qua display object). Is the original file kept in another part
of the HIC's file management space?

Challenge 9.5
Look at the interaction patterns on a mobile phone that you have available. What
combination of buttons and displays does what? Identify the 'select' key or select pattern.
Identify the 'move down' pattern. Does it always work in the same way or are there
different patterns for 'move down a menu' and 'move down through some text'? Compare
the existence of patterns in phone design to those in the design of car controls.
■ ■ ■ - - ..........................................................


- ■ ■ ■ ■ ■ ■



- -


Diagrammatic techniques
The diagrammatic techniques we presented in Section 9.4 are concerned with repre­
senting the structure of a system. By contrast, the design of interactions is concerned
with processes. In many design situations there will be a need to provide a structured



Part II • Techniques for designing interactive systems

‘dialogue’ between the system and the person using it. The system may need to elicit
particular pieces of data in a particular sequence, or to guide people through a series
of actions, or to present a number of related options together. Dataflow diagrams are a
good way of showing the logical steps required to complete some interaction. The exam­
ple in Figure 9.11 shows the steps needed to complete a simple transaction with a cash
machine. It shows the data needed to go in, the processes (shown as circles) that need to
be undertaken and the data that flows out. It also shows the stores of data (boxes) that
will be needed. With a logical flow diagram such as this, designers can debate where
the hum an-computer interface should be and where certain functions should take
place. Notice that this representation is as independent of technology as possible. Some
data, called ‘ID’, is needed but this representation does not say that this should be a card
and PIN. It could be, but it could equally be some new technology such as iris recogni­
tion, or fingerprint recognition.
Several other methods are available for representing interactions. Sequence models
are one; task structure diagrams are another (Chapter 11). Use cases can be used to
describe the interactions, as can simple tabular layouts that show people actions on one
side and system responses on the other. Another common diagrammatic technique is
the state transition network (STN). This shows how a system moves from one state to
another depending on the actions by the user. Figure 9.12 shows an STN for the ATM
example. Notice both the similarities and the differences between the two represen­
tations. STNs come in a variety of forms and can be powerful techniques for thinking
about and creating interactions.

Chapter 9 • Design

Summary and key points
Conceptual and physical design will happen in any system development, and conceptual
modelling, in particular, is a key activity for designers. In this chapter we looked at the
importance of conceptual modelling and at conceptual exploration of design spaces. All
projects will need to consider the conceptual model and underlying metaphor of the
systems, because it is this that leads to people developing their own conceptual model their mental model - of the system. In addition to developing the conceptual model we
have highlighted the need for designing interactions and packaging design ideas into a
design language.
• Designers need to explore the concepts and blends in their designs.
• Designers can understand objects and actions in the existing, proposed system by
analysing the scenario corpus.
• Designing interactions is concerned with allocating functions to people or devices
and hence arriving at a set of interaction patterns.
• Designers should ensure that there is a consistent design language in terms of both
the patterns of interaction and representational aspects of design.




Techniques for designing interactive systems

1 Discuss the underlying conceptual model for the following activities: using
an ATM; buying a plane ticket on the Web; using a public information kiosk;
setting a VCR to record a programme.

2 In the design of electronic calendars, there are lots of functions such as making
regular appointments (say an appointment every Wednesday at 3 pm). In
shared calendar systems appointments can be made by other people. There
are even some systems that let software 'agents' make appointments. Discuss
issues of the allocation of functions between people and software in the
context of electronic calendars.

Further reading
McLuhan, M. (1994) Understanding Media: The Extensions of Man. MIT Press, Cambridge, MA.
This is not a book for the faint-hearted, nor for those who want some simple answers. It is some­
thing of a psychedelic tour through a 7960s view of the coming age of media. It makes you think.
Newell, A. and Simon, H. (1972) Human Problem Solving. Prentice-Hall, Englewood Cliffs, NJ.
Rheinfrank, J. and Evenson, S. (1996) Design languages. In Winograd, T. (ed.), Bringing
Design to Software. ACM Press, New York. A good chapter on design languages and how they
have been used in everything from houses in Nantucket to knitting patterns.
van Harmelen, M. (ed.) (2001) Object Modeling and User Interface Design: Designing
Interactive Systems. Addison-Wesley, Boston, MA. This book is a collection of papers provid­
ing different methods for conceptual and physical design. Constantine and Lockwood's chapter
‘Structure and style in use cases for user interface design' covers much the same ground as pre­
sented here but is wholly based around use cases. Constantine and Lockwood define 'essential'
use cases that are basically the same as our conceptual scenarios. William Hudson's chapter
'Toward unified models in user-centred and object-oriented design' gives a very comprehensive
overview of different methods and how they might all be brought together.
Graham, I. (2003) A Pattern Language for Web Usability. Addison-Wesley, Harlow. An excel­
lent example of the development of a pattern language, this time to help designers to design
good websites.

Getting ahead
Blackwell, A.F. (2006) The reification of metaphor as a design tool. ACM Transactions on
Computer-Human Interaction (TOCHI), 13(4), 490-530.
Imaz, M. and Benyon, D.R. (2005) Designing with Blends: Conceptual Foundations of
Human Computer Interaction and Software Engineering. MIT Press, Cambridge, MA.
Saffer, Dan (2007) Designing for Interaction. New Riders, Indianapolis, IN.

Web links
Bill Verplank is at
The accompanying website has links to relevant websites. Go to

Chapter 9

Comments on challenges


Challenge 9.1
Personal, direct, fun, impromptu, young, quick, pervasive, h o t .. . occur to me, but there are almost
infinite possibilities here. There are no right or wrong answers; it depends on your own perceptions
and feelings.

Challenge 9.2
The window is one of the components of the original 'desktop metaphor'that has led to the current
operating systems Windows 8 and OS X. The window allows you to look in on something. 'Cut
and paste' comes from journalism where paragraphs of stories were cut up and pasted (with glue)
onto paper in a different order. A bootstrap was attached to riding boots so that people would pull
themselves up. Most people are familiar with manila folders kept in a filing cabinet that needs to be
opened up to see what is inside. Interestingly, since a folder contains many files, a computer folder
is more like a drawer in a filing cabinet and a computer file is more like a real folder.

Challenge 9.3
Thinking of physical diaries is one way to come up with possible metaphors: pocket diaries, desk
diaries, the diary of personal events that you might keep, the diary of future events in an area such
as sports, a diary of events for a local society or club. This might lead to the metaphor of a pocket
diary in which the interface had 'pages' that could be 'turned'. The diary of events leads to a wallchart type of display with the days of the month laid out. The personal diary might lead to ideas
such as secrecy and security, being able to write free-flowing text rather than having a regimented
date- and event-driven design that a business diary suggests.

Challenge 9.4
Nouns: arts festival, city, three weeks, August, Edinburgh International Festival, Edinburgh Fringe
Festival, book festival, film festival, jazz festival, related events, performers, orchestras, composers,
ballet troupes, theatres, the Traverse, mavericks, Demarco, events, venues. Verbs: takes place, con­
sists of, features, started.
The main objects are the same as the nouns; there are the different types of festival and events,
different types of performers, theatres and venues. We also know a bit more about some of these:
1200 events, 150 venues, etc. The main activities express relationships between the objects. In this
way the underlying conceptual model of the domain begins to emerge.
Events take place at a venue/theatre. A festival consists of events and features performers, and so on.

Challenge 9.5
Most phones will have these standard patterns, though exactly how they are implemented varies
widely between different makes and varies over time. Preferences shift from four-way rocker keys
to arrow keys and back again. Presumably designs will settle down at some stage, as they have
done, for example, in the design of car controls, which were highly non-standard but which now
have similar patterns of interaction - for signalling, for windscreen washing, turning the lights on,
and so on.



Chapter 10




Evaluation is the fourth main process of interactive systems design
that we identified in Chapter 3. By evaluation we mean reviewing,
trying out or testing a design idea, a piece of software, a product or a
service to discover whether it meets some criteria. These criteria will
often be summed up by the guidelines for good design introduced
in Chapter 4, namely that the system is learnable, effective and
accommodating. But at other times the designer might be more
interested in some other characteristic of the design. The designer is
concerned not just with surface features such as the meaningfulness
of icons, but also with whether the system is fit for its purpose,
enjoyable, engaging and so on.

Introduction 215

10.2 Expert evaluation 217
10.3 Participant-based
evaluation 220
10.4 Evaluation in practice 224
10.5 Evaluation: further issues 230
Sum m ary and key points 233
Exercises 234
Further reading 235
W eb links 235
Com m ents on challenges 236

After studying this chapter you should be able to:
• Appreciate the uses of a range of generally applicable evaluation
techniques designed for use with and without users
• Understand expert-based evaluation methods
• Understand participant-based evaluation methods
• Apply the techniques in appropriate contexts.

Chapter 10 • Evaluation




The techniques in this chapter will allow you to evaluate many types of product, system
or service. Evaluation of different types of system, or evaluation in different contexts,
may offer particular challenges. (For example, evaluating mobile devices, or services
delivered by a mobile device, are explored in more detail in Chapter 19).
Evaluation is closely tied to the other key activities of interactive systems design,
understanding, design and envisionment. In particular, many of the techniques dis­
cussed in Chapter 7 on understanding are applicable to evaluation. Evaluation is
also critically dependent on the form of envisionment used to represent the system.
You will only be able to evaluate features that are represented in a form appropriate
for the type of evaluation. There are also issues concerning who is involved in the

Challenge 10.1
Collect several advertisements for
small, personal technologies such
as that shown in Figure 70.7.
What claims are the advertisers
making about design features
and benefits? What issues does
this raise for their evaluation?

G et th e u ltim ate
m u ltim ed ia
e xp e rie n ce w ith

Figure 10.1 Sony Ericsson T100 mobile phone


In our human-centred approach to design, we evaluate designs right from the earliest
idea. For example, in the case study in Chapter 6, very early ideas for the HIC were
mocked up and reviewed, to be followed later by more realistic prototyping and test­
ing of a partially finished system and finally by evaluation of the near-complete device
in its intended home setting. There are two main types of evaluation. One involves a
usability expert, or an interaction designer, reviewing some form of envisioned version
of a design: expert-based methods. The other involves recruiting people to use an envi­
sioned version of a system: participant methods. Where possible these people should
be representative of the people at whom the system is aimed (sometimes called ‘endusers’). This is the preferred choice for ‘in-house’ systems where the designer has access
to the target population. Alternatively, the participants may be other people (perhaps
other designers, students or whoever happens to be around), who are invited to play the
part of the people who will use the system. The characteristics of the target population
can be captured through personas.

pe rs0 nas are described
in C h ap ter 3



Part II • Techniques for designing interactive systems

Evaluation occurs throughout the interaction design process. At different stages, dif­
ferent methods will be more or less effective. The form of envisionment of the future
systems is also critical to what can be evaluated.
Obtaining feedback to inform early design concepts
You may need to evaluate initial concepts, especially if the application is novel. Here,
quick paper prototypes can help, or even software if this can be produced rapidly.
Evaluations of competitor products or previous versions of technology can also feed into
the design process at this stage.
Deciding between different design options
During development, designers have to decide between options, for example between
voice input and touchscreen interaction for a shared electronic household wall-planner
or between different sequences for order processing functions.

Checking for usability problems
Testing will identify potential problems once a stable version of the technology is availa­
ble. This needs to respond when a participant activates a function, but it does not require
the whole system to be fully operational (a horizontal prototype). Alternatively, the sys­
tem may be completely functional, but only in some parts (a vertical prototype). What
is important is that there is still time to fix problems. What happens all too frequently
is that you are asked to check that interaction is ‘user-friendly’just before development
is completed. Very often all that can be changed are minor issues such as the position,
colour or labelling of on-screen buttons. It is best to be helpful in these circumstances.
If you make a note of problems that could have been solved easily if identified sooner,
you can exploit these examples (tactfully) to justify evaluation work at an earlier stage
in the next project.
Evaluation of the types described above is sometimes termed formative evaluation,
because the results help to form - or shape - the design.
Assessing the usability of a finished product
This may be to test against in-house guidelines, or formal usability standards such as
ISO 9241, or to provide evidence of usability required by a customer, for example the
time to complete a particular set of operations. Government departments and other
public bodies often require suppliers to conform to accessibility standards and health
and safety legislation.
This type of evaluation is often termed summative evaluation.

As a means of involving people in the design process
In the participatory design approach, stakeholders help designers set the goals for the
evaluation work. Involving stakeholders has great benefits in terms of eventual uptake
and use of the technology. (Of course, this applies only to technology that is tailor-made
for defined communities, rather than off-the-shelf products.) For example, in a redevel­
opment of a Web-based gallery showcasing the work of disadvantaged artists, as many
of the artists themselves as possible were involved in evaluating the new designs, thus
preserving the sense of community which the site aimed to embody (Macleod, 2002).
A number of methods of involving people in the design process were discussed in
Chapter 7 on understanding and Chapter 8 on envisionment (prototyping). Susanne
Bodker’s Design Collabatorium (Bodker and Buur, 2002) is another example.

Chapter 10 • Evaluation
r .


..............I.... . .................... ■« ...■■■■—... ........................... .

Expert evaluation

L_______________ _______________________________________________________________________________ A

A simple, relatively quick and effective method of evaluation is to get an interaction
design, or usability, expert to look at the system and try using it. As we said in the intro­
duction this is no substitute for getting real people to use your design, but expert evalu­
ation is effective, particularly early in the design process. Experts will pick up common
problems based on this experience, and will identify factors that might otherwise inter­
fere with an evaluation by non-experts.
However, to help the experts structure their evaluation, it is useful to adopt a par­
ticular approach. This will help to focus the expert’s critique on the most relevant
aspects for the purpose. The general approach to expert evaluation is that the expert
will walk through representative tasks or scenarios of use. Additionally they may
adopt one of the personas. Thus expert evaluation is tied in to scenario-based design
(and central to it).

<- Scenario-based design is
covered in Chapter 3 and the
importance of evaluation in
Chapter 2

Heuristic evaluation
Heuristic evaluation refers to a number of methods in which a person trained in HCI and
interaction design examines a proposed design to see how it measures up against a list of
principles, guidelines or ‘heuristics’ for good design. This review may be a quick discus­
sion over the shoulder of a colleague, or may be a formal, carefully documented process.
There are many sets of heuristics to choose from, both general-purpose and those
relating to particular application domains, for example heuristics for Web design. Below
is a brief list of the design principles - or heuristics - that we introduced earlier. (You
should refer back to Chapter 4 for the details.)




Ideally, several people with expertise in interactive systems design should review the
interface. Each expert notes the problems and the relevant heuristic, and suggests a
solution where possible. It is also helpful if a severity rating, say on a scale of 1 to 3,
is added, according to the likely impact of the problem, as recommended by Dumas
and Fox (2012) in their comprehensive review of usability testing. However, they
also note the disappointing level of correlation amongst experts in rating severity of
Evaluators work independently and then combine results. They may need to work
through any training materials and be briefed by the design team about the functional­
ity. The scenarios used in the design process are valuable here.

Discount usability engineering
The list of design principles above can be summarized by the three overarching usability
principles of learnability (principles 1-4), effectiveness (principles 5-9) and accommo­
dation (principles 10-12). If time is very short, a quick review of the design against
this triad can produce reasonably useful results. This is known as a discount heuristic

<- An example of discount
heuristic evaluation was pro­
vided in the HIC case study in
Chapter 6


Part II • Techniques for designing interactive systems

This approach to evaluation was pioneered by Jakob Nielsen (1993) and enthusi­
astically followed by many time-pressured evaluation practitioners. It is now used for
any ‘quick and dirty’ approach to evaluation where the aim is to get useful, informed
feedback as soon as possible. Once again a number of usability experts ‘walk through’
concrete scenarios, preferably accompanied by personas, and inspect the design for

Challenge 10.2
Carry out a quick review of the controls for a domestic device, e.g. a stove, microwave or
washing machine, for learnability, effectiveness and accommodation.

Unless there is no alternative, you should not evaluate your own designs. It is extremely
difficult to ignore your knowledge of how the system works, the meaning of icons or
menu names and so on, and you are likely to give the design the ‘benefit of the doubt’ or
to find obscure flaws which few users will ever happen upon.
Woolrych and Cockton (2000) conducted a large-scale trial of heuristic evaluation.
Evaluators were trained to use the technique, then evaluated the interface to a draw­
ing editor. The editor was then trialled by customers. Comparison of findings showed
that many of the issues identified by the experts were not experienced by people (false
positives), while some severe difficulties were missed by the inspection against heuris­
tics. There were a number of reasons for this. Many false positives stemmed from a ten­
dency by the experts to assume that people had no intelligence or even common sense.
As for ‘missing’ problems, these tended to result from a series of mistakes and miscon­
ceptions, often relating to a set of linked items, rather than isolated misunderstand­
ings. Sometimes heuristics were misapplied, or apparently added as an afterthought.
Woolrych and Cockton conclude that the heuristics add little advantage to an expert
evaluation and the results of applying them may be counter-productive. They (and
other authors) suggest that more theoretically informed techniques such as the cogni­
tive walkthrough (see below) offer more robust support for problem identification. It is
very evident that heuristic evaluation is not a complete solution. At the very least, the
technique must be used together with careful consideration of people and their reallife skills. Participant evaluation is required to get a realistic picture of the success of a
Heuristic evaluation therefore is valuable as formative evaluation, to help the
designer improve the interaction at an early stage. It should not be used as a summative
assessment, to make claims about the usability and other characteristics of a finished
product. If that is what we need to do, then we must carry out properly designed and
controlled experiments with a much greater number of participants. However, the more
controlled the testing situation becomes, the less it is likely to resemble the real world,
which leads us to the question of ‘ecological validity.

Ecological validity

In real life, people multitask, use several applications in parallel or in quick succession,
are interrupted, improvise, ask other people for help, use applications intermittently
and adapt technologies for purposes the designers never imagined. We have unpre­
dictable, complex but generally effective coping strategies for everyday life and the

— ........ -....-...- - .........................

'.......... ..... - .................... - ...... J

Chapter 10


technologies supporting it. The small tasks which are the focus of most evaluations are
usually part of lengthy sequences directed towards aims which change according to
circumstances. All of this is extremely difficult to reproduce in testing, and often delib­
erately excluded. So the results of most user testing can only ever be indicative of issues
in real-life usage. Practitioners and researchers are not unaware of this problem and a
number of solutions have been proposed. They include:
• Ethnographically informed observations of technologies in long-term use (although
this is more often undertaken earlier in the design - evaluation cycle) - see Chapter 7
• Having users keep diaries, which can be audiovisual as well as written - there is
more about this in Chapter 7
• Collecting 'bug' reports — often these are usability problems - and help centre

Cognitive walkthrough
Cognitive walkthrough is a rigorous paper-based technique for checking through the
detailed design and logic of steps in an interaction. It is derived from the human infor­
mation processor view of cognition and closely related to task analysis (Chapter 11).
In essence, the cognitive walkthrough entails a usability analyst stepping through the
cognitive tasks that must be carried out in interacting with technology. Originally devel­
oped by Lewis et al. (1990) for applications where people browse and explore infor­
mation, it has been extended to interactive systems in general (Wharton et a l ., 1994).
Aside from its systematic approach, the great strength of the cognitive walkthrough is
that it is based on well-established theory rather than the trial and error or a heuristically based approach.
Inputs to the process are:
• An understanding of the people who are expected to use the system
• A set of concrete scenarios representing both (a) very common and (b) uncommon
but critical sequences of activities
• A complete description of the interface to the system - this should comprise both a
representation of how the interface is presented, e.g. screen designs, and the correct
sequence of actions for achieving the scenario tasks, usually as a hierarchical task
analysis (HTA).
Having gathered these materials together, the analyst asks the following four questions
for each individual step in the interaction:

Will the people using the system try to achieve the right effect?
Will they notice that the correct action is available?
Will they associate the correct action with the effect that they are trying to achieve?
If the correct action is performed, will people see that progress is being made towards
the goal of their activity? (modified from Wharton et a l, 1994, p. 106)

If any of the questions is answered in the negative, then a usability problem has been
identified and is recorded, but redesign suggestions are not made at this point. If the
walkthrough is being used as originally devised, this process is carried out as a group
exercise by analysts and designers together. The analysts step through usage scenar­
ios and the design team are required to explain how the user would identify, carry
out and monitor the correct sequence of actions. Software designers in organizations
with structured quality procedures in place will find some similarities to program code

H ierarchical task
analysis (H TA ) is discussed
in C h ap ter 11


Part II • Techniques for designing interactive systems

Several cut-down versions of the technique have been devised. Among the best docu­
mented are:
• The ‘cognitive jogthrough’ (Rowley and Rhoades, 1992) - video records (rather than
conventional minutes) are made of walkthrough meetings, annotated to indicate sig­
nificant items of interest, design suggestions are permitted, and low-level actions are
aggregated wherever possible.
• The ‘streamlined cognitive walkthrough’ (Spencer, 2000) - designer defensiveness
is defused by engendering a problem-solving ethos, and the process is streamlined
by not documenting problem-free steps and by combining the four original questions
into two (ibid., p. 355):
- Will people know what to do at each step?
- If people do the right thing, will they know that they did the right thing, and are
making progress towards their goal?
Both these approaches acknowledge that detail may be lost, but this is more than com­
pensated for by enhanced coverage of the system as a whole and by designer buy-in to
the process. Finally, the cognitive walkthrough is very often practised (and taught) as a
technique executed by the analyst alone, to be followed in some cases by a meeting with
the design team. If a written report is required, the problematic interaction step and the
difficulties predicted should be explained. Other checklist approaches have been sug­
gested, such as the Activity Checklist (Kaptelinin et al. 1999), but have not been widely
taken up by other practitioners.

Challenge 10.3
A joint walkthrough session between evaluators and designers can work well, but there
can be drawbacks. Suggest what these might be and how you might overcome them.

While expert-based evaluation is a reasonable first step, it will not find all problems, par­
ticularly those that result from a chain of ‘wrong’ actions or are linked to fundamental
misconceptions. Woolrych and Cockton (2001) discuss this in detail. Experts even find
problems that do not really exist - people overcome many minor difficulties using a mix­
ture of common sense and experience. So it is really important to complete the picture with
some real people trying out the interaction design. The findings will always be interest­
ing, quite often surprising and occasionally disconcerting. From a political point of view,
it is easier to convince designers of the need for changes if the evidence is not simply one
‘expert’view, particularly if the expert is relatively junior. The aim is to trial the design with
people who represent the intended target group in as near realistic conditions as possible.




Participant-based evaluation

Whereas expert, heuristic evaluations can be carried out by designers on their own,
there can be no substitute for involving some real people in the evaluation. Participant
evaluation aims to do exactly that. There are many ways to involve people that require
various degrees of cooperation. The methods range from designers sitting with partici­
pants as they work through a system to leaving people alone with the technology and
observing what they do through a two-way mirror.

Chapter 10


Cooperative evaluation
Andrew Monk and colleagues (Monk et al., 1993) at the University of York (UK) devel­
oped cooperative evaluation as a means of maximizing the data gathered from a sim­
ple testing session. The technique is ‘cooperative’ because participants are not passive
subjects but work as co-evaluators. It has proved a reliable but economical technique in
diverse applications. Table 10.1 and the sample questions are edited from Appendix 1
in Monk etal. (1993).

Table 10.1 Guidelines for cooperative evaluation


1 Using the scenarios prepared earlier, write a draft
list of tasks.

Tasks must be realistic, doable with the software, and
explore the system thoroughly.

2 Try out the tasks and estimate how long they will
take a participant to complete.

Allow 50 per cent longer than the total task time for
each test session.

3 Prepare a task sheet for the participants.

Be specific and explain the tasks so that anyone can

4 Get ready for the test session.

Have the prototype ready in a suitable environment
with a list of prompt questions, notebook and pens
ready. A video or audio recorder would be very useful

5 Tell the participants that it is the system that is
under test, not them; explain and introduce the

Participants should work individually - you will not be
able to monitor more than one participant at once.
Start recording if equipment is available.

6 Participants start the tasks. Have them give you
running commentary on what they are doing, why
they are doing it and difficulties or uncertainties
they encounter.

Take notes of where participants find problems or do
something unexpected, and their comments. Do this
even if you are recording the session. You may need
to help if participants are stuck or have them move to
the next task.

7 Encourage participants to keep talking.

Some useful prompt questions are provided below.

8 When the participants have finished, interview
them briefly about the usability of the prototype
and the session itself. Thank them.

Some useful questions are provided below. If you have
a large number of participants, a simple questionnaire
may be helpful.

9 Write up your notes as soon as possible and
incorporate into a usability report.
Sample questions during the evaluation:
• What do you want to do?
• What were you expecting to happen?
• What is the system telling you?
• Why has the system done that?
• What are you doing now?
Sample questions after the session:
• What was the best/worst thing about the prototype?
• What most needs changing?
• How easy were the tasks?
• How realistic were the tasks?
• Did giving a commentary distract you?



Part II • Techniques for designing interactive systems

Participatory heuristic evaluation
The developers of participatory heuristic evaluation (Muller et al., 1998) claim that it
extends the power of heuristic evaluation without adding greatly to the effort required.
An expanded list of heuristics is provided, based on those of Nielsen and Mack (1994) but of course you could use any heuristics such as those introduced earlier (Chapter 4).
The procedure for the use of participatory heuristic evaluation is just as for the expert
version, but the participants are involved as ‘work-domain experts’ alongside usability
experts and must be briefed about what is required.

Co-discovery is a naturalistic, informal technique that is particularly good for capturing
first impressions. It is best used in the later stages of design.
The standard approach of watching individual people interacting with the technol­
ogy, and possibly ‘thinking aloud’ as they do so, can be varied by having participants
explore new technology in pairs. For example, a series of pairs of people could be given
a prototype of a new digital camera and asked to experiment with its features by taking
pictures of each other and objects in the room. This tends to elicit a more naturalistic
flow of comment, and people will often encourage each other to try interactions that
they might not have thought of in isolation. It is a good idea to use people who know
each other quite well. As with most other techniques, it also helps to set users some
realistic tasks to try out.
Depending on the data to be collected, the evaluator can take an active part in the
session by asking questions or suggesting activities, or simply monitor the interaction
either live or using a video-recording. Inevitably, asking specific questions skews the
output towards the evaluator’s interests, but does help to ensure that all important
angles are covered. The term ‘co-discovery’ originates from Kemp and van Gelderen
(1996) who provide a detailed description of its use.

Living Labs

Living Labs is a European approach to evaluation that aims to engage as many people
as possible in exploring new technologies. There are a number of different structures
for Living Labs. For example, Nokia has teamed up with academics and other manufac­
turers of mobile devices to hand out hundreds of early prototype systems to students to
see how they use them. Other labs work with elderly people in their homes to explore
new types of home technologies. Others work with travellers and migrant workers to
uncover what new technologies can do for them.
The key idea behind Living Labs is that people are both willing and able to contrib- j
ute to designing new technologies and new services and it makes sense for compa­
nies to work with them. The fact that the discussions and evaluation take place in the
life-context of people, and often with large numbers of people, gives the data a strong
ecological validity.

— ------------ ------------- - - .............. -..................

.... -


Controlled experiments
Another way of undertaking participant evaluation is to set up a controlled experi­
ment. Controlled experiments are appropriate where the designer is interested in par­
ticular features of a design, perhaps comparing one design to another to see which

Chapter 10 • Evaluation

is better. In order to do this with any certainty the experiment needs to be carefully
designed and run.
The first thing to do when considering a controlled experiment approach to evalu­
ation is to establish what it is that you are looking at. This is the independent variable.
For example, you might want to compare two different designs of a website, or two dif­
ferent ways of selecting a function on a mobile phone application. Later we describe an
experiment that examined two different ways of presenting an audio interface to select
locations of objects (Chapter 18). The independent variable was the type of audio
interface. Once you have established what it is you are looking at, you need to decide
how you are going to measure the difference. These are the dependent variables. You
might want to judge which Web design is better based on the number of clicks needed
to achieve some task; speed of access could be the dependent variable for selecting a
function. In the case of the audio interface, accuracy of location was the dependent
Once the independent and dependent variables have been agreed, the experiment
needs to be designed to avoid anything getting in the way of the relationship between
independent and dependent variables. Things that might get in the way are learning
effects, the effects of different tasks, the effects of different background knowledge,
etc. These are the confounding variables. You want to ensure a balanced and clear rela­
tionship between independent and dependent variables so that you can be sure you are
looking at the relationship between them and nothing else.
One possible confounding variable is that the participants in any experiment are not
balanced across the conditions. To avoid this, participants are usually divided up across
the conditions so that there are roughly the same number of people in each condition
and there are roughly the same number of males and females, young and old, experi­
enced and not. The next stage is to decide whether each participant will participate in all
conditions (so-called within-subject design) or whether each participant will perform in
only one condition (so-called between-subject design). In deciding this you have to be
wary of introducing confounding variables. For example, consider the learning effects
that happen if people perform a similar task on more than one system. They start off
slowly but soon get good at things, so if time to complete a task is a measure they inevi­
tably get quicker the more they do it. This effect can be controlled by randomizing the
sequence in which people perform in the different conditions.
Having got some participants to agree to participate in a controlled experiment, it is
tempting to try to find out as much as possible. There is nothing wrong with an experi­
ment being set up to look at more than one independent variable, perhaps one being
looked at between subjects and another being looked at within subjects. You just have to
be careful how the design works. And, of course, there is nothing wrong with interview­
ing them afterwards, or using focus groups afterwards to find out other things about
the design. People can be videoed and perhaps talk aloud during the experiments (so
long as this does not count as a confounding variable) and this data can also prove use­
ful for the evaluation.
A controlled experiment will often result in some quantitative data: the measures
of the dependent values. This data can then be analysed using statistics, for example
comparing the average time to do something across two conditions, or the average
number of clicks. So, to undertake controlled experiments you will need some basic
understanding of probability theory, of experimental theory and, of course, of statis­
tics. Daunting as this might sound, it is not so very difficult given a good textbook.
Experimental Design and Statistics (Miller, 1984) is a widely used text, and another
good example is Cairns and Cox (2008) Research Methods for Human-Computer



Part II • Techniques for designing interactive systems

Challenge 10.4
You have just completed a small evaluation project for a tourist information 'walk-upand-use' kiosk designed for an airport arrivals area. A heuristic evaluation by you (you
were not involved with the design itself) and a technical author found seventeen potential
problems, of which seven were graded severe enough to require some redesign and the
rest were fairly trivial.
You then carried out some participant evaluation. You had very little time for this, testing
with only three people. The test focused on the more severe problems found in the heuristic
evaluation and the most important functionality (as identified in the requirements
analysis). Your participants - again because of lack of time and budget - were recruited
from another section of your own organization which is not directly involved in interactive
systems design or build, but the staff do use desktop PCs as part of their normal work. The
testing took place in a quiet corner of the development office.
Participants in the user evaluation all found difficulty with three of the problematic
design features flagged up by the heuristic evaluation. These problems were essentially
concerned with knowing what information might be found in different sections of the
application. Of the remaining four severe problems from heuristic evaluation, one person
had difficulty with all of them, but the other two people did not. Two out of the three test
users failed to complete a long transaction where they tried to find and book hotel rooms
for a party of travellers staying for different periods of time.
What, if anything, can you conclude from the evaluation? What are the limitations of
the data?


Evaluation in practice

A survey of 103 experienced practitioners of human-centred design conducted in
2000 (Vredenburg et al., 2002) indicates that around 40 per cent of those surveyed
conducted ‘usability evaluation’, around 30 per cent used ‘informal expert review’ and
around 15 per cent used ‘formal heuristic evaluation’ (Table 10.2). These figures do not
indicate where people used more than one technique. As the authors note, some kind
of cost-benefit trade-off seems to be in operation. Table 10.2 shows the benefits and
weaknesses perceived for each method. For busy practitioners, the relative economy of
review methods often compensates for the better information obtained from user test­
ing. Clearly the community remains in need of methods that are both light on resources
and productive of useful results.
The main steps in undertaking a simple but effective evaluation project are:
1 Establish the aims of the evaluation, the intended participants in the evaluation, the
context of use and the state of the technology; obtain or construct scenarios illustrat­
ing how the application will be used.
2 Select evaluation methods. These should be a combination of expert-based review
methods and participant methods.
3 Carry out expert review.
4 Plan participant testing; use the results of the expert review to help focus this.
5 Recruit people and organize testing venue and equipment.
6 Carry out the evaluation.
7 Analyse results, document and report back to designers.

Chapter 10 • Evaluation

Table 10.2 Perceived costs and benefits of evaluation methods. A '+' sign denotes a benefit, and a a
weakness. The numbers indicate how many respondents mentioned the benefit or weakness.
Formal heuristic

r e v ie w


+ (9)

+ 02)

Availability of expertise

- (3 )

-(4 )


In fo r m a l e x p e r t

Availability of information

Usability evaluation
-(6 )

+ (3)


+ 00)

+ (22)

User involvement

-(7 )


-(3 )

Compatibility with practice

- (3 )


-(4 )

Ease of documentation

- (3 )

Validity/quality of results

+ (6)

+ (7)

+ (8)

Understanding context



- (3 )

Credibility of results

+ (7)

Source: Adapted from Vredenburg, K., Mao, J.-Y., Smith, P.W. and Carey, T. (2002) A survey of user-centred design practice, Proceedings ofSIGCHI
conferenceonhumanfactors incomputingsystems, MN, 20-25 April, pp. 471 -8, Table 3. © 2002 ACM, Inc. Reprinted by permission

Aims of the evaluation
Deciding the aim(s) for evaluation helps to determine the type of data required. It is
useful to write down the main questions you need to answer. For example in the evalua­
tion of the early concept for a virtual training environment the aims were to investigate:
• Do the trainers understand and welcome the basic idea of the virtual training
• Would they use it to extend or replace existing training courses?
• How close to reality should the virtual environment be?
• What features are required to support record keeping and administration?
The data we were interested in at this stage was largely qualitative (non-numerical), so
appropriate data gathering methods were interviews and discussions with the trainers.
If the aim of the evaluation is the comparison of two different evaluation designs
then much more focused questions will be required and the data gathered will be more
quantitative. In the virtual training environment, for example, some questions we asked
• Is it quicker to reach a particular room in the virtual environment using mouse, cur­
sor keys or joystick?
• Is it easier to open a virtual door by clicking on the handle or selecting the ‘open’ icon
from a tools palette?
Figure 10.2 shows the evaluation in progress. Underlying issues were the focus on speed
and ease of operation. This illustrates the link between analysis and evaluation - in this
case, it had been identified that these qualities were crucial for the acceptability of the
virtual learning environment. With questions such as these, we are likely to need quan­
titative (numerical) data to support design choices.

2 25


Part II • Techniques for designing interactive systems

Metrics and measures
What is to be measured and how? Table 10.3 shows some common usability metrics
and ways in which they can be measured, adapted from the list provided in the usability
standard ISO 9241 part 11 and using the usability definition o f‘effectiveness, efficiency
and satisfaction’ adopted in the standard. There are many other possibilities.
Such metrics are helpful in evaluating many types of applications, from small mobile
communication devices to office systems. In most of these there is a task - something the
participant needs to get done - and it is reasonably straightforward to decide whether
Table 10.3 Common usability metrics

Effectiveness measures

Efficiency measures

Satisfaction measures

O v e r a ll u s a b ilit y

• Percentage of tasks
successfully completed
• Percentage of users
successfully completing

• Time to complete a task
• Time spent on
non-productive actions

• Rating scale for
• Frequency of use if this is
voluntary (after system is

M e e ts n e e d s

• Percentage of advanced
tasks completed
• Percentage of relevant
functions used

• Time taken to complete
tasks relative to
minimum realistic time

• Rating scale for
satisfaction with
advanced features

• Percentage of tasks
completed successfully at
first attempt

• Time taken on first
attempt to complete task
• Time spent on help

• Rate of voluntary
use (after system is

• Percentage of tasks
completed successfully
after a specified period
of non-use

• Time spent re-learning
functionsNumber of
persistent errors

• Frequency of reuse (after
system is implemented)

• Number of functions
• Percentage of users who
manage to learn to a
pre-specified criterion

• Time spent on help
• Time to learn to criterion

• Rating scale for ease of

o f tra in e d o r
e x p e r ie n c e d
u se rs
M e e t s n e e d s fo r
w a lk u p a n d u se

M e e t s n e e d s fo r
in fr e q u e n t o r
in te rm it te n t u se

L e a rn a b ility

Source: ISO 9241 -11:1998 Ergonomic requirements for office work with visual display terminals (VDTs), extract of Table B.2

Chapter 10



the task has been achieved successfully or not. There is one major difficulty: deciding
the acceptable figure for, say, the percentage of tasks successfully completed. Is this 95
per cent, 80 per cent or 50 per cent? In some (rare) cases clients may set this figure.
Otherwise a baseline may be available from comparative testing against an alternative
design, a previous version, a rival product, or the current manual version of a process
to be computerized. But the evaluation team still has to determine whether a metric
is relevant. For example, in a complex computer-aided design system, one would not
expect most functions to be used perfectly at the first attempt. And would it really be
meaningful if design engineers using one design were on average two seconds quicker
in completing a complex diagram than those using a competing design? By contrast,
speed of keying characters may be crucial to the success of a mobile phone. There are
three things to keep in mind when deciding metrics:
• Just because something can be measured, it doesn’t mean it should be.
• Always refer back to the overall purpose and context of use of the technology.
• Consider the usefulness of the data you are likely to obtain against the resources it
will take to test against the metrics.
The last point is particularly important in practice.

Challenge 10.5
W h y is le a r n a b ility m o re im p o r t a n t f o r s o m e a p p lic a tio n s th a n f o r o th e r s ? T h in k o f s o m e


e x a m p le s w h e re it m ig h t n o t b e a v e r y s ig n ific a n t fa c t o r in u sa b ility .

The most important people in evaluation are the people who will use the system.
Analysis work should have identified the characteristics of these people, and repre­
sented these in the form of personas. Relevant data can include knowledge of the activi­
ties the technology is intended to support, skills relating to input and output devices,
experience, education, training and physical and cognitive capabilities.
You need to recruit at least three and preferably five people to participate in tests. Nielsen’s
recommended sample of 3-5 participants has been accepted wisdom in usability practice for

Games and other applications designed for entertainment pose different questions for
evaluation. While we may still want to evaluate whether the basic functions to move
around a game environment, for example, are easy to learn, efficiency and effectiveness
in a wider sense are much less relevant. The 'purpose' here is to enjoy the game, and
time to complete, for example, a particular level may sometimes be less important than
experiencing the events that happen along the way. Similarly, multimedia applications
are often directed at intriguing users or evoking emotional responses rather than hav­
ing the achievement of particular tasks in a limited period of time. In contexts of this
type, evaluation centres on probing user experience through interviews or question­
naires. Read and MacFarlane (2000), for example, used a rating scale presented as a
'smiley face vertical fun meted when working with children to evaluate novel interfaces.
Other measures which can be considered are observational: the user's posture or facial
expression, for instance, may be an indicator of engagement in the experience.

Relevant characteristics of
people are summarized
in Chapter 2



Part II • Techniques for designing interactive systems

over a decade. However, some practitioners and researchers advise that this is too few. We
consider that in many real-world situations obtaining even 3-5 people is difficult, so we con­
tinue to recommend small test numbers as part of a pragmatic evaluation strategy.
However, testing such a small number makes sense only if you have a relatively homo­
geneous group to design for - for example, experienced managers who use a customer
database system, or computer games players aged between 16 and 25. If you have a hetero­
geneous set of customers that your design is aimed at, then you will need to run 3-5 people
from each group through your tests. If your product is to be demonstrated by sales and mar­
keting personnel, it is useful to involve them. Finding representative participants should be
straightforward if you are developing an in-house application. Otherwise participants can
be found through focus groups established for marketing purposes or, if necessary, through
advertising. Students are often readily available, but remember that they are only repre­
sentative of a particular segment of the population. If you have the resources, payment can
help recruitment. Inevitably, your sample will be biased towards cooperative people with
some sort of interest in technology, so bear this in mind when interpreting your results.
If you cannot recruit any genuine participants - people who are really representative
of the target customers - and you are the designer of the software, at least have someone
else try to use it. This could be one of your colleagues, a friend, your mother or anyone
you trust to give you a brutally honest reaction. Almost certainly, they will find some
design flaws. The data you obtain will be limited, but better than nothing. You will, how­
ever, have to be extremely careful as to how far you generalize from your findings.
Finally, consider your own role and that of others in the evaluation team if you have
one. You will need to set up the tests and collect data, but how far will you become
involved? Our recommended method for basic testing requires an evaluator to sit with
each user and engage with them as they carry out the test tasks. We also suggest that
for ethical reasons and in order to keep the tests running, you should provide help if the
participant is becoming uncomfortable, or completely stuck. The amount of help that
is appropriate will depend on the type of application (e.g. for an information kiosk for
public use you might provide only very minimal help), the degree of completeness of the
test application and, in particular, whether any help facilities have been implemented.

The test plan and task specification
A plan should be drawn up to guide the evaluation. The plan specifies:
• Aims of the test session
• Practical details, including where and when it will be conducted, how long each ses­
sion will last, the specification of equipment and materials for testing and data col­
lection, and any technical support that may be necessary
• Numbers and types of participant
• Tasks to be performed, with a definition of successful completion. This section also
specifies what data should be collected and how it will be analysed.
You should now conduct a pilot session and fix any unforeseen difficulties. For example,
task completion time is often much longer than expected, and instructions may need

Reporting usability evaluation results to the design team
However competent and complete the evaluation, it is only worthwhile if the results are
acted upon. Even if you are both designer and evaluator, you need an organized list of
findings so that you can prioritize redesign work. If you are reporting back to a design/
development team, it is crucial that they can see immediately what the problem is, how
significant its consequences are, and ideally what needs to be done to fix it.

Chapter 10

The report should be ordered either by areas of the system concerned, or by severity
of problem. For the latter, you could adopt a three- or five-point scale, perhaps ranging
from hvould prevent participant from proceeding further’ to ‘minor irritation’. Adding
a note of the general usability principle concerned may help designers understand why
there is a difficulty, but often more specific explanation will be needed. Alternatively,
sometimes the problem is so obvious that explanation is superfluous. A face-to-face
meeting may have more impact than a written document alone (although this should
always be produced as supporting material) and this would be the ideal venue for show­
ing short video clips of participant problems.
Suggested solutions make it more probable that something will be done. Requiring
a response from the development team to each problem will further increase this prob­
ability, but may be counter-productive in some contexts. If your organization has a for­
mal quality system, an effective strategy is to have usability evaluation alongside other
test procedures, so usability problems are dealt with in the same way as any other fault.
Even without a full quality system, usability problems can be fed into a ‘bug’ reporting
system if one exists. Whatever the system for dealing with design problems, however,
tact is a key skill in effective usability evaluation.

An example small-scale evaluation
This is the process implemented by a postgraduate student to evaluate three different
styles of interface for the editing functions on photo CDs. It is not a perfect example, but
rather illustrates making the best use of limited resources.
Four experts reviewed the three interfaces in stage 1. Stage 2 consisted of a small
number of short interviews of potential customers designed to elicit typical uses for
the software. These were used to develop scenarios and test tasks. Finally, stage 3 was a
detailed participant-based evaluation of the interfaces. This focused on exploration of
the issues identified by the experts and was structured around the scenarios and tasks
derived from stage 2. Stages 1 and 3 are described here.
Each person carrying out the heuristic evaluation had experience of interface evalu­
ation and a working knowledge of interface design. They familiarized themselves with
a scenario describing the level of knowledge of real customers and their aims in using
the product, together with a list of seven generic usability heuristics, then examined the
software. They spent approximately one hour per interface and explored all functions,
listing all usability issues discovered.
Participant testing involved a group of three males and three females aged between 25
and 35. Half were students and half were professionals; they had varying degrees of PC
experience. With such a small sample, it was impossible to reflect the entire spectrum of
the target population, but it was considered that these would provide a reasonable insight
into any problems. After drawing up a test plan, scenarios and tasks were derived from
background interview data and task analysis (see Chapter 11), supplemented by the results
of the expert evaluation. Five main tasks were identified. Since the software was for home
use, the tests were carried out in a home environment using equipment equivalent to that
identified for the target population. Participants undertook the testing individually and
were reassured that the focus was not on their skills but on any problems with the software.
Written instructions emphasizing this and listing the five tasks were supplied, together with
a scenario to set the scene. Each session lasted no more than 45 minutes to avoid fatigue.
Each participant started with simple tasks to gain familiarity with the interface. The
main tasks consisted of selecting an image and performing a number of typical edit­
ing tasks. For example, participants were asked to select a specific image and edit it by
rotating it the correct way round, switching to black and white, cropping the picture





Part II • Techniques for designing interactive systems

and adjusting the brightness and contrast before saving the new image. The intention
was to give an overview of the functionality and a chance to learn the more compli­
cated tools. Parts 3 and 4 of the tests asked the participants to perform almost identical
tasks to those already achieved. The aim here was to monitor the 'learnability' of the
interface. The test was completed by accessing the slideshow option of each interface.
Where possible, the participant was also asked to attempt to import images from the
hard disk. No help except that available from the software was provided.
Each sub-task required the participant to rate the functions on a scale from 1 (easy) to 5
(difficult) before proceeding to the next. During the session, the evaluator noted participant
behaviour and verbalizations. Participants were prompted to verbalize where necessary.
Finally, the participant undertook a short task based on the operation of a mobile
phone - intended as an indicator of competence in operating a commonplace artefact before completing a brief questionnaire. This collected details of experience of PCs and
software packages.

Challenge 10.6
D e sig n a s im p le o n e - p a g e p ro fo r m a f o r a u s a b ility e v a lu a tio n su m m a ry .

- .......... I ............................ I ..........


--------------------------- --------------- -- --------- ------------ ■-----------—

------- —

.................................- .......... „

............. .............. ............................ ................ ..




. , ....U l.lll


HU. .

10.5 Evaluation: further issues

Of course, there are lots and lots of specifics associated with evaluation. Many are
considered in the chapters on contexts. In this section we look at a number of particu­
lar issues.

Evaluation without being there
With the arrival of Internet connectivity, people can participate in evaluations with­
out being physically present. If the application itself is Web-based, or can be installed
remotely, instructions can be supplied so that users can run test tasks and fill in and
return questionnaires in soft or hard copy. On-line questionnaires and crowd sourcing
methods are appropriate here (see Chapter 7).

Physical and physiological measures

Figure 10.3 A participant being eye-tracked
(Source: Mullin et a t 2001, p 42. Courtesy ofjim Mullin)

Eye-movement tracking (or ‘eye tracking’) can show par­
ticipants’ changing focus on different areas of the screen.
This can indicate which features of a user interface have
attracted attention, and in which order, or capture largerscale gaze patterns indicating how people move around
the screen. Eye tracking is very popular with website
designers as it can be used to highlight which parts of the
page are most looked at, so-called ‘hot spots’, and which
are missed altogether. Eye-tracking equipment is headmounted or attached to computer monitors, as shown in
Figure 10.3.

Chapter 10 • Evaluation

Eye-tracking software is readily available to provide maps of the screen. Some of it
can also measure pupil dilation, which is taken as an indication of arousal. Your pupil
dilates if you like what you see. Physiological techniques in evaluation rely on the fact
that all our emotions - anxiety, pleasure, apprehension, delight, surprise and so on generate physiological changes.
The most common measures are of changes in heart rate, the rate of respiration,
skin temperature, blood volume pulse and galvanic skin response (an indicator of the
amount of perspiration). All are indicators of changes in the overall level of arousal,
which in turn may be evidence of an emotional reaction. Sensors can be attached to the
participant’s body (commonly the fingertips) and linked to software which converts the
results to numerical and graphical formats for analysis. But there are many unobtrusive
methods too, such as pressure sensors in the steering wheel of a games interface, or sen­
sors that measure if the participant is on the edge of their seat.
Which particular emotion is being evoked cannot be deduced from the level of
arousal alone, but must be inferred from other data such as facial expression, posture
or direct questioning. Another current application is in the assessment of the degree of
presence - the sense o f‘being there’ evoked by virtual environments (see Figure 10.4).
Typically, startling events or threatening features are produced in the environment
and arousal levels measured as people encounter them. Researchers at University
College London and the University of North Carolina at Chapel Hill (Usoh et al., 1999,
2000; Insko, 2001, 2003; Meehan, 2001) have conducted a series of experiments when
measuring arousal as participants approach a ‘virtual precipice’. In these circumstances
changes in heart rate correlated most closely with self-reports of stress.

-> There is more about the
role of emotion in interactive
systems design in Chapter 22

Figure 10.4 A 20-foot 'precipice' used in
evaluating presence in virtual environments

BeingThere: Concepts,
Effects andMeasurement of User PresenceinSynthetic
Environment, Inkso, B.E., Measuring presence. Copyright
(Source: Reprinted from

2003, with permission from IOS Press)

Evaluating presence
Designers of virtual reality - and some multimedia - applications are often concerned
with the sense of presence, of being ‘there’ in the virtual environment rather than ‘here’
in the room where the technology is being used. A strong sense of presence is thought
to be crucial for such applications as games, those designed to treat phobias, to allow
people to ‘visit’ real places they may never see otherwise, or indeed for some workplace



Part II • Techniques for designing interactive systems

applications such as training to operate effectively under stress. This is a very current
research topic, and there are no techniques that deal with all the issues satisfactorily.
The difficulties include:
• The sense of presence is strongly entangled with individual dispositions, experiences
and expectations. Of course, this is also the case with reactions to any interactive
system, but presence is an extreme example of this problem.
• The concept of presence itself is ill-defined and the subject of much debate among
researchers. Variants include the sense that the virtual environment is realistic, the
extent to which the user is impervious to the outside world, the retrospective sense of
having visited rather than viewed a location, and a number of others.
• Asking people about presence while they are experiencing the virtual environment
tends to interfere with the experience itself. On the other hand, asking questions ret­
rospectively inevitably fails to capture the experience as it is lived.
The measures used in evaluating presence adopt various strategies to avoid these prob­
lems, but none are wholly satisfactory. The various questionnaire measures, for exam­
ple the questionnaire developed by NASA scientists Witmer and Singer (1998) or the
range of instruments developed at University College and Goldsmiths College, London
(Slater, 1999; Lessiter et ah, 2001), can be cross-referenced to measures which attempt
to quantify how far a person is generally susceptible to being ‘wrapped up’ in experi­
ences mediated by books, films, games and so on as well as through virtual reality. The
Witmer and Singer Immersive Tendencies Questionnaire (Witmer and Singer, 1998) is
the best known of such instruments. However, presence as measured by presence ques­
tionnaires is a slippery and ill-defined concept. In one experiment, questionnaire results
showed that while many people did not feel wholly present in the virtual environment
(a re-creation of an office), some of them did not feel wholly present in the real-world
office either (Usoh et al., 2000). Less structured attempts to capture verbal accounts of
presence include having people write accounts of their experience, or inviting them to
provide free-form comments in an interview. The results are then analysed for indica­
tions of a sense of presence. The difficulty here lies in defining what should be treated
as such an indicator, and in the layers of indirection introduced by the relative verbal
dexterity of the participant and the interpretation imposed by the analyst.
Other approaches to measuring presence attempt to avoid such layers of indirection
by observing behaviour in the virtual environment or by direct physiological measures.

Challenge 10.7
What indicators of presence might one measure using physiological techniques? Are there
any issues in interpreting the resulting data?

Evaluation at home
People at home are much less of a ‘captive audience’ for the evaluator than those at
work. They are also likely to be more concerned about protecting their privacy and gen­
erally unwilling to spend their valuable leisure time in helping you with your usability
evaluation. So it is important that data gathering techniques are interesting and stimu­
lating for users, and make as little demand on time and effort as possible. This is very
much a developing field and researchers continue to adapt existing approaches and
develop new ones. Petersen et al. (2002), for example, were interested in the evolu­
tion over time of relationships with technology in the home. They used conventional
interviews at the time the technology (a new television) was first installed, but followed

Chapter 10 • Evaluation

this by having families act out scenarios using it. Diaries were also distributed as a data
collection tool, but in this instance the non-completion rate was high, possibly because
of the complexity of the diary pro forma and the incompatibility between a private diary
and the social activity of television viewing.
An effective example of this in early evaluation is reported in Baillie et al. (2003) and
Baillie and Benyon (2008). Here the investigator supplied users with Post-its to cap­
ture their thoughts about design concepts (Figure 10.5). An illustration of each differ­
ent concept was left in the home in a location where it might be used, and users were
encouraged to think about how they would use the device and any issues that might
arise. These were noted on the Post-its, which were then stuck to the illustration and
collected later.
Where the family is the focus of interest, techniques should be engaging for children
as well as adults - not only does this help to ensure that all viewpoints are covered, but
working with children is a good way of drawing parents into evaluation activities.

Figure 10.5 Post-it notes
(Source: David Benyon)

Challenge 10.8
Suggest some ways in which 6-9-year-olds could take part in evaluation activities
situated in the home.

Summary and key points
This chapter has presented an overview of the key issues in evaluation. Designing the
evaluation of an interactive system, product or service requires as much attention and
effort as designing any other aspect of that system. Designers need to be aware of the

-> Probes described in
Chapter 7 are relevant here




II • Techniques for designing interactive systems
possibilities and limitations of different approaches and, in addition to studying the the­
ory, they need plenty of practical experience.
• Designers need to focus hard on what features of a system or product they want to
• They need to think hard about the state that the system or product is in and hence
whether they can evaluate those features.
• There are expert-based methods of evaluation.
• There are participant-based methods of evaluation.
• Designers need to design their evaluation to fit the particular needs of the contexts of
use and the activities that people are engaged in.

1 Using the list of heuristics from Section 10.2, carry out a heuristic evaluation of
the features dealing with tables in your usual word processor and the phone
book in your cellphone.
2 Think about the following evaluation. A call centre operator answers enquiries
about insurance claims. This involves talking to customers on the phone
while accessing their personal data and claim details from a database. You are
responsible for the user testing of new database software to be used by the
operators. What aspects of usability do you think it is important to evaluate,
and how would you measure them?
Now think about the same questions for an interactive multimedia website
which is an on-line art gallery. The designers want to allow users to experience
concrete and conceptual artworks presented in different media.
3 (More advanced) Identify any potential difficulties with the evaluation
described in Box 10.2. What would you do differently?
4 (More advanced) You are responsible for planning the evaluation of an
interactive toy for children. The toy is a small, furry, talking animal character
whose behaviour changes over time as it 'learns' new skills and in response
to how its owner treats it, for example how often it is picked up during a
24-hour period. The designers think it should take around a month for all the
behaviours to develop. Children interact with the toy by speaking commands
(it has voice recognition for 20 words), stroking its ears, picking it up, and
pressing 'spots' on the animal's back which are, in effect, buttons triggering
different actions. No instructions will be provided; children are intended to
find out what the toy does by trial and error.
Design an evaluation process for the toy, explaining the reasons behind your


How do we know that the criteria we use for evaluation reflect what is
important to users? Suggest some ways in which we can ground evaluation
criteria in user wants and needs.

6 An organization with staff in geographically dispersed offices has introduced
desktop video-conferencing with the aim of reducing resources spent on
'unnecessary' travel between offices. Working teams often involve people
at different sites. Before the introduction of video-conferencing, travel was
M H M H B B H M H M fi


■ ir

Chapter 10

regarded as rather a nuisance, although it did afford the opportunity to
'show one's face' at other sites and take care of other business involving
people outside the immediate team. One month after the introduction of the
technology, senior managers have asked for a 'comprehensive' evaluation of
the system. Describe what techniques you would adopt, what data you would
hope to gain from their use, and any problems you foresee with the evaluation.
7 Critically discuss the strengths and weaknesses of the 'standard' user evaluation
techniques of task-based interviews and observation in settings beyond the
workplace. What additional methods could be used in these domains?

Ijfji Further reading
Research Methods for Human-Computer Interaction.
Cambridge University Press, Cambridge.
Cairns, P. and Cox, A.L. (2008)

Cockton, G., Woolrych, A. and Lavery, D. (2012) Inspection-based evaluations. In Jacko.J.A.

The Human-Computer Interaction Handbook: Fundamentals, Evolving Technologies and
Emerging Applications, 3rd edn. CRC Press, Taylor and Francis, Boca Ratun, FL, pp. 1279-98.


Monk, A., Wright, P., Haber, J. and Davenport, L. (1993) Improving Your Human-Computer
Interface: a Practical Technique. BCS, Practitioner Series, Prentice-Hall, New York and Hemel
Hempstead. This book includes a full description of cooperative usability evaluation. It may now
be hard to purchase but should be available through libraries.

G etting ahead
Doubleday, A., Ryan, M., Springett, M. and Sutcliffe, A. (1997) A com parison of usabil­

Proceedings of DIS '97 Conference, Amsterdam,
Netherlands. ACM Press, New York, pp. 101-10. This compares the results of heuristic evalua­
tion with user testing in the evaluation of an information retrieval interface. A good example of
the continuing stream of research into the relative efficacy of different approaches to evaluation.
ity techniques for evaluating design.

Nielsen, J. (1993) Usability Engineering. Academic Press. New York. Nielsen's classic exposition
of his 'discount' approach. Highly practical, but as discussed in this chapter and in Chapter 19, later
work has suggested that the results obtained can have some limitations.

Robson, C. (1994) Experiment, Design and Statistics in Psychology. Penguin, London.
Beyond the IT Productivity Paradox: Assessment Issues.
Wiley, Chichester. This provides a good overview on the evaluation of workplace information
technologies and use from the information systems perspective.
Willcocks, L. and Lester, S. (1998)

The British HCI Group's website often carries current debates about
usability evaluation.
The accompanying website has links to relevant websites. Go to
w w w .p e a r s o n e d .c o .u k / b e n y o n


2 35



Techniques for designing interactive systems

Comments on challenges

................ a~-\

Challenge 10.1
The 'answer' to this, of course, depends on the material collected. But you will probably have found
adverts appealing to aspirational needs and desires - status, style and so on - which standard usa­
bility techniques do not deal with particularly well.

Challenge 10.2
The control panel for our dishwasher is very simply designed. It has four programmes, each of
which is listed and numbered on the panel with a brief explanatory label (e.g. 'rinse') and a rather
less self-explanatory icon. The dial to set the programme has starting points labelled with the pro­
gramme numbers. The design is learnable - even without the handbook it is clear what each pro­
gramme does and how to select it. It is also effective - I can easily select the programme and the
movement of the dial shows how far the cycle has progressed. It is accommodating to some extent
in that I can interrupt the process to add more dishes, but fails (among other deficiencies here) to
cope with the needs of partially sighted or blind users - something that could apparently be done
fairly simply by adding tactile labels.

Challenge 10.3
Potential difficulties include over-defensiveness on the part of the designers and consequently
lengthy explanations of design rationale and a confrontational atmosphere. It would be a good
idea to hold a preliminary meeting to diffuse these feelings from the start. Also, asking the design­
ers the walkthrough questions may help people to identify issues themselves rather than feeling
under attack.

Challenge 10.4
It is likely that the three problems found in both evaluations are genuine, not merely induced by
the testing procedures. You cannot really conclude very much about the remaining four, but should
review the relevant parts of the design. The difficulties with long transactions are also probably
genuine, and unlikely to have been highlighted by heuristics. In all these cases you should ideally
test the redesigns with real representative users.

Challenge 10.5
Learnability - in terms of time taken to become familiar with functionality - can be less cru­
cial, for example, when the application is intended for intensive, sustained long-term use. Here
people expect to invest some effort in becoming acquainted with powerful functionality; also
the overall learning time is relatively small compared with that spent using the software produc­
tively. Applications for professionals, such as computer-aided design, desktop publishing, scien­
tific analysis software and the myriad of products intended for use by computer programmers,
fall into this category. This doesn't mean that overall usability and good design cease to matter,
but there will be more emphasis on issues such as fit to activity rather than superficial ease of

Challenge 10.6
Points to consider here:

Avery short summary
Structure (by topic, severity or some other ordering principle)
A rating scale for severity
Brief suggested solutions
Links to supporting data
Space for explanations where necessary.

Chapter 10

Challenge 10.7
Changes in heart rate, breathing rate and skin conductance (among other things) will all indicate
changes in arousal levels. The issues include teasing out the effects of the virtual environment from
extraneous variables such as apprehension about the experiment itself, or something completely
unrelated which the participant is thinking of.

Challenge 10.8
One technique which has been tried is to have the children draw themselves using the technology
in question - perhaps as a strip cartoon for more complicated operations. Older children could add
'thinks' bubbles. Possibilities are limited only by your imagination.

• Evaluation


Chapter 11
T ask an a lysis



11.1 Goals, tasks and actions 239

The notion of a 'task' has been central to work in human-computer
interaction since the subject started. Undertaking a task analysis is a
very useful technique - or rather set of techniques - for understanding
people and how they carry out their work. Looking at the tasks that
people do, or the tasks that they will have to do because of some
redesigned system, is a necessary part of human-centred design. This

11.2 Task analysis and systems
design 241
11.3 Hierarchical task analysis 243
11.4 GOMS: a cognitive model of
procedural knowledge 245
11.5 Structural knowledge 246
11.6 Cognitive work analysis 250
Summary and key points 252
Exercises 252
Further reading 252
Web links 253
Comments on challenges 253

chapter provides some philosophical background on what task analysis
is and where it fits into interactive systems design. It then provides
practical advice on doing different types of task analysis.
After studying this chapter you should be able to:
• Understand the difference between goals, tasks and actions
• Undertake a hierarchical task analysis
• Undertake a procedural cognitive task analysis
• Understand the importance of considering a structural view of a

Chapter 11 • Task analysis


11.1 Goals, tasks and actions
Some authors consider ‘task analysis’ to encompass all manner of techniques (such as
interviewing, observation, development of scenarios, etc.). We do not. We consider task
analysis to be a specific view of interactive systems design that leads to specific tech­
niques. This chapter looks more formally at the concept of task, how to undertake task
analyses and what benefit designers might get from such analyses. In the final section
we look at the importance of understanding a structural perspective of a domain.
The distinction between the key concepts in task analysis - goals, tasks and actions may be identified as follows:
A task is a goal together with some ordered set of actions.
The concept of task derives from a view of people, or other agents, interacting with tech­
nologies trying to achieve some change in an application domain. Taken together, the
people and technology constitute what is sometimes called a ‘work system’, which is
separate from the ‘application domain’. Dowell and Long (1998) emphasize that the
application domain (or simply ‘domain’) is an abstraction of the real world, i.e. some
abstract representation (such as a database, a website or an iPhone app). Importantly,
task analysis is concerned with some aspects of the performance of a work system with
respect to a domain. This performance may be the amount of effort to learn a system,
to reach a certain level of competence with a system, the time taken to perform certain
tasks, and so on. This conceptualization is shown in Figure 11.1.

Figure 11.1 Task analysis
is concerned with the
performance of work by a
work system

Diaper’s full definition of task analysis (Diaper, 2004) is:
Work is achieved by the work system making changes to the application domain. The
application domain is that part of the assumed real world that is relevant to the func­
tioning of the work system. A work system in HCI consists of one or more human and
computer components and usually many other sorts of thing as well. Tasks are the
means by which the work system changes the application domain. Goals are desired
future states of the application domain that the work system should achieve by the tasks
it carries out. The work system's performance is deemed satisfactory as long as it contin­
ues to achieve its goals in the application domain. Task analysis is the study of how work
is achieved by tasks.

We called the work
system the 'people-technology'
system in Chapter 3


Part II

Techniques for designing interactive systems

This view of the separation of work system and domain is not shared by everyone but
this definition does result in some useful task analysis techniques for systems analysis
and design. Other definitions are as follows.

States and transitions
w ere introduced in C h ap ter 9

A goal is a state of the application domain that a work system wishes to achieve. Goals
are specified at particular levels of abstraction.
This definition allows for artificial entities such as technologies or agents or some
combination to have goals. For example, we might be studying the organizational goals
of a company, or the behaviour of a software system in terms of its goals. It is not just
people who have goals; the work system as a whole may have goals. For this reason
the term ‘agent’ is often used to encompass both people and software systems that are
actively and autonomously trying to achieve some state of the application domain. The
term ‘technology’ is used to encompass physical devices, information artefacts, software
systems and other methods and procedures.
For example, an agent might have a goal such as to write a letter, to record a pro­
gramme on TV, or to find the strongest mobile phone signal. The assumption is that
the domain is in one state now - no letter written, the TV programme not recorded, the
signal not confirmed as the strongest - and the agent has to undertake some activities,
i.e. some tasks, in order to get it into the required state.
Usually a goal can be achieved in a variety of different ways. So the first thing the
agent has to decide is which technology to use to achieve the goal. For recording a TV
programme, for example, an agent could use the following technologies:

Ask a friend to record it.
Press ‘Rec’ on the PVR (personal video recorder).
Set the timer using a manual setting.
Set the timer using an on-screen TV guide.

Of course, the agent needs to know quite a lot about each of these technologies and the
pros and cons of each and will select different ones at different times depending on the
circumstances. The agent may misunderstand some of the technologies and so may not
take the optimum course of action. The selection of a technology will depend on the
agent’s knowledge of the functions, structure and purpose of particular technologies;
and this knowledge may be quite erroneous. Once a technology has been decided upon,
the tasks can now be defined.
Tasks and actions
A task is a structured set of activities required, used, or believed to be necessary by an
agent to achieve a goal using a particular technology. A task will often consist of sub­
tasks where a subtask is a task at a more detailed level of abstraction. The structure of
an activity may include selecting between alternative actions, performing some actions
a number of times and sequencing of actions.
The task is broken down into more and more detailed levels of description until it
is defined in terms of actions. Actions are ‘simple tasks’. Whereas a task might include
some structure such as doing things in a particular sequence, making decisions as to
alternative things to do (selection) and doing things several times (iteration), an action
does not. This structure is often called a plan or method.
An action is a task that has no problem solving associated with it and which does not
include any control structure. Actions and tasks will be different for different people.
For example, in the case of recording a TV programme, if the programme is just
about to come on it might be best to press ‘Rec’ on the PVR which would start recording

Chapter 11

Task analysis

immediately. This brings its own problems as the PVR might be tuned to the wrong
channel depending on the particular connections between the devices. Alternatively,
the agent could set the timer manually. Using an on-screen menu system is more labori­
ous as the agent has to turn the TV on to use the on-screen menu. If the agent is not very
well informed about the operation of the system, the agent may fiddle around selecting
the PVR channel, finally getting to the on-screen programming and so on. The agent
may do things that are strictly unnecessary because the agent had a poor conceptualiza­
tion, their mental model of the device.

Challenge 11.1
Write down the task structure for manually recording a programme using a PVR.
Think about the decisions that an agent would need in order to undertake this task
and about the differences between tasks and actions for different agents with different
knowledge. Discuss with a friend or colleague.

Task analysis methods can be divided into two broad categories: those concerned with
the logic of the task - the sequence of steps that need to be undertaken by a work system
to achieve a goal - and those concerned with cognitive aspects. Cognitive task analysis
is concerned with understanding what cognitive processes the work system will have
to undertake in order to achieve a goal. Cognition is concerned with thinking, solving
problems, learning, memory, and their mental models.
People also have knowledge of how to do things in general and how to do things with
specific technologies. People make use of things in the environment (such as displays
on a computer screen or notes on a piece of paper) as part of the cognitive processes.
Cognitive task analysis has a long-established tradition in human-computer interaction,
with a large number of methods coming from a variety of slightly different backgrounds.
Most of the theoretical treatments of cognition and action presented in Chapter 23 have
resulted in some technique applied to the design or evaluation of interactive systems.
In terms of the goals, tasks and actions, we need to consider both the goal-task map­
ping (knowing what to do to achieve some goal) and the task-action mapping (knowing
how to do it). There is also a need to consider the goal formation stage - knowing that
you can do something in the first place. In addition to this procedural knowledge, peo­
ple have structural knowledge. Structural knowledge concerns knowing about concepts
in a domain and knowing how those concepts are related. This sort of knowledge is par­
ticularly useful when things go wrong, when understanding the relationships between
the components in a system will help with troubleshooting.

11.2 Task analysis and system s design
There are many views on, and methods for, task analysis and task design. As noted
previously, some authors equate task analysis with the whole of systems development.
Others equate methods of task analysis with methods of requirements generation and
evaluation. Yet others distinguish task analysis (understanding existing tasks) from task
design (envisioning future tasks). Diaper and Stanton (2004a) provide a comprehen­
sive overview of 30 different views. One thing that people agree upon is that a task
analysis will result in a task model, though, as we will see, these models can take very
different forms.


Cognition is discussed
in Chapter 23



Part II • Techniques for designing interactive systems

Balbo et al. (2004) emphasize the expressive power of different methods in their
taxonomy of task analysis techniques. For example, they focus on whether a tech­
nique captures optionality (is a task m andatory or optional in pursuing a goal?),
parallelism (can tasks be performed in parallel?) or non-standard actions such as
error handling or automatic feedback. They also classify methods along the follow­
ing axes:
• The goal of using the notation. By this they mean the stage in the development life
cycle; is it best for understanding, design, envisionment or evaluation?
• Its usability for communication. Some task analysis techniques can be very hard to
read and understand, particularly those that are based on a grammar rather than
graphical notation.
• Its usability for modelling tasks. Task analysis methods have to fit into the software
development process and be used and understood by software engineers. It has long
been a problem that software engineers do not have ready access to a good task anal­
ysis technique. Some methods are intended to assist in the automatic generation of
systems (see Further thoughts box).
• The adaptability of a task analysis technique to new types of system, new aims or new
requirements. To what extent is the technique extensible to other purposes? (e.g.
a task analysis technique aimed specifically at website design may not be very
Diaper and Stanton (2004b) make an important observation regarding many task
analysis techniques, namely that they are usually mono-teleological. That is to say, they
assume that the agent or work system has a single purpose which gives rise to its goal.
Teleology is the study of purposes, causes and reasons, a level of description of activi­
ties that is missing from most task analysis approaches. In reality, of course, people and
work systems may be pursuing multiple goals simultaneously.
Task analysis is an important part of systems development, but it is a term that
encompasses a number of different views. It is undertaken at different times during sys­
tems development for different purposes.


Model-based user interface design
One particular branch of task analysis concerns the formal representation of systems
so that the whole system, or part of it, can be automatically generated by a computer
system from the specification or model. Work on model-based design has continued,
without much success, in several areas. In user interface design several systems have
been tried (see Abed et al., 2004, for a review) that represent systems at the domain
level, an abstract level of description and the physical level of different styles of widget
such as scroll bars, windows, etc. One aim of the model-based approaches is to enable
different versions of a system to be automatically generated from the same underlying
model. For example, by applying different physical models an interface for a smart­
phone, a computer and a tablet could be generated from the same abstract and domain
models. Stephanidis (2001) uses this approach to generate different interfaces for peo- *
pie with varying levels of ability.
Model-based approaches have also been tried in software engineering for many
years (e.g. Benyon and Skidmore, 1988), again with limited success. The screen-design
systems that automate the generation at the physical layer (such as Delphi, Borland and
VB) have been highly successful, but automatically linking this to an abstract level of
description proves difficult.

Chapter 11

Task analysis


• During the understanding process, for example, the task analysis should aim to be as
independent as possible from the device (or technology), for the aim is to understand
the essential nature of the work in order to inform new designs.
• During the design and evaluation of future tasks, task analysis focuses on the achieve­
ment of work using a particular technology (i.e. a particular design) and hence is
During understanding, task analysis is concerned with the practice of work, with the
current allocation of function between people and technologies, with existing problems
and with opportunities for improvement. During design and evaluation, task analysis is
concerned with the cognition demanded by a particular design, the logic of a possible
design and the future distribution of tasks and actions between people and technologies.
Task analysis is in many ways similar to scenario-based design, for tasks are just sce­
narios in which the context and other details have been stripped away. Task analysis is
best applied to one or two key activities in a domain. Task analysis is not quick or cheap
to do, so it should be used where there is likely to be the best pay-off. In an e-commerce
application, for example, it would be best to do a task analysis on the buying-and-payingfor-an-item task. In designing the interface for a mobile phone, key tasks would be
making a call, answering a call, calling a person who is in the address book and finding
your own phone number.
In the rest of this chapter we look at two analysis techniques. The first is based on
hierarchical task analysis (HTA) and is concerned with the logic of a task. The second,
based on the goals, operators, methods, selection rules (GOMS) method, is con­
cerned with a cognitive analysis of tasks, focusing on the procedural knowledge needed
to achieve a goal. This is sometimes called ‘how to do it’ knowledge. Finally we look at
understanding structural knowledge, sometimes called ‘what it is’ knowledge.

11.3 Hierarchical task analysis
Hierarchical task analysis (HTA) is a graphical representation of a task structure based
on a structure chart notation. Structure charts represent a sequence of tasks, subtasks
and actions as a hierarchy and include notational conventions to show whether an action
can be repeated a number of times (iteration) and the execution of alternative actions
(selection). Sequence is usually shown by ordering the tasks, subtasks and actions from
left to right. Annotations can be included to indicate plans. These are structured paths
through the hierarchy to achieve particular goals. For example, making a call using a
mobile phone has two main routes through the hierarchy of tasks and subtasks. If the
person’s number is in the phone’s address book then the caller has to find the number
and press ‘call’. If it is not, the caller has to type the number in and press ‘call’.
HTA was developed during the 1960s and has appeared in a variety of guises since
then. Stanton (2003) gives a detailed account. HTA uses a structured diagram repre­
sentation, showing the various tasks and actions in boxes and using levels to show the
hierarchy. Figure 11.2 shows an example for using an ATM (cash machine).
There are a number of notational conventions that can be used to capture key fea­
tures of the tasks. We recommend using an asterisk in the box to show that an action
may be repeated a number of times (iteration) and a small ‘o’ to show optionality. The
plans are used to highlight sequencing. Others (e.g. Stanton, 2003) like to show deci­
sion points as parts of the plans.
HTA is not easy. The analyst must spend time getting the description of the tasks
and subtasks right so that they can be represented hierarchically. Like most things in

Scenario-based design is
described in Chap ter 3



Techniques for designing interactive systems

Figure 11.2 Hierarchical task model for a portion of an ATM

C h ap ter 21 discusses
hum an erro r and action slips

interactive systems design, undertaking a hierarchical task analysis is highly iterative
and you will not get it right first time. The analyst should return to the task list and try
to redefine the tasks so that they can be represented hierarchically.
HTA appears in many different methods for interactive systems design. For example,
Stanton (2003) uses it as part of his method for error identification. He develops an HTA
model of a system and then works through the model looking for possible error situations. At the action level (bottom level of an HTA), people might make a slip such as
pressing the wrong button. What happens if they do this? At the task and subtask levels
the analyst can consider what type of task it is and hence what types of error might occur.
Annett (2004) provides a step-by-step guide to how to do an HTA:
1 Decide on the purpose of the analysis. This is typically to help with systems design or
to design training materials.
2 Define the task goals.
3 Data acquisition. How are you going to collect data? Observation, getting people to
use a prototype, etc.
4 Acquire data and draft a hierarchical diagram.
5 Recheck validity of decomposition with stakeholders.
6 Identify significant operations and stop when the effects of failure are no longer
7 Generate and test hypotheses concerning factors affecting learning and performance.
Lim and Long (1994) use HTA slightly differently in their HCI development method,
called MUSE (Method for Usability Engineering). They illustrate their approach using a
‘Simple ATM’ example as shown in Figure 11.2. This shows that the ‘Simple ATM’ con­
sists of two subtasks that are completed in sequence: Present Personal ID and Select
Service. Present Personal ID consists of two further subtasks: Enter Card and Enter PIN.
In its turn, Enter PIN consists of a number of iterations of the Press Digit action. Select
Service consists of either Withdraw Cash or Check Balance.

Chapter 11 • Task analysis

11.4 GOMS: a cognitive model of procedural
GOMS is the most famous and long-lasting of a large number of cognitive task analysis
methods (Kieras, 2012). GOMS focuses on the cognitive processes required to achieve
a goal using a particular device. The aim is to describe tasks in terms of the following:
• Goals. What are people trying to do using some system (e.g. make a call using a cell
• Operators. These are the actions that the system allows people to perform, such as
clicking on menus, scrolling through lists, pressing buttons and so on.
• Methods. These are sequences of subtasks and operators. Subtasks are described at a
more abstract level than operators - things such as ‘select name from address book’
or ‘enter phone number’.
• Selection rules. These are the rules that people use to choose between methods of
achieving the same subtask (if there are options). For example, to select a name from
an address book a person could scroll through the names or type in the first letter and
jump to a part of the address book.
There are many different ‘flavours’ of GOMS, focusing on different aspects of a task,
using different notations, using different constructs. In this book we do not claim to
teach GOMS as a method, but just to alert readers to its existence and provide some
illustrative examples. Kieras (2004) provides his version and John (2003) provides hers.
Looking at the constructs in GOMS, it is clear that the method is applicable only if
people know what they are going to do. John (2003) emphasizes that selection rules are
‘well-learned’ sequences of sub-goals and operators. GOMS is not a suitable analytical
method where people are problem-solving. Also it is mainly applicable to systems being
used by a single person where it can give accurate estimates of performance and help
designers think about different designs.
John (2003) gives the example of a GOMS analysis in project Ernestine. She and
co-worker Wayne Gray constructed 36 detailed GOMS models for telephone opera­
tors using their current workstation and for them using a new proposed workstation.
The tasks such as answer call, initiate call and so on are broken down into the detailed
operations that are required, such as enter command, read screen and so on. Times
for these operations are then allocated and hence the overall time for the task can be
The new workstation had a different keyboard and screen layout, different keying
procedures and system response time. The company believed the new workstation
would be more effective than the old. However, the results of the modelling exercise
predicted that the new workstation would be on average 0.63 second slower than the
old. In financial terms this cost an additional $2m a year. Later, field trials were under­
taken which confirmed the predicted results.
John (2003) provides much more detail on this story, but perhaps the most impor­
tant thing is that the modelling effort took two person-months and the field trial took 18
months and involved scores of people. A good model can be effective in saving money. A
portion of the model is shown in Figure 11.3.
Undertaking a GOMS analysis shares with HTA the need to describe, organize and
structure tasks, subtasks and actions hierarchically. As we have seen, this is not always
easy to do. However, once a task list has been formulated, working through the model is
quite straightforward. Times can be associated with the various cognitive and physical
actions and hence one can derive the sort of predictions discussed by John (2003).



Part II • Techniques for designing interactive systems

G O M S goal hierarchy

O bserved behavior

goal: hand le-calls
. goal: handle-call
. . goal: initiate-call
. . . goal: receiv e -in fo rm a tio n





W orkstation : Beep






W orkstation : Displays so urce information




goal: re q u e st-in fo rm atio n







greet-custom er

T A O : ‘N e w England Telephone, may 1 help you?’



goal: enter-w ho -p ays
. goal: receiv e -in fo rm a tio n








goal: e n te r-in fo rm atio n






T A O : hit F 1 key






T A O : hit 14 numeric keys



listen-to-custom er

C u sto m er: O p e ra to r bill this to 412-555-1212-1234



goal: e n te r-b illin g -rate
. goal: receiv e -in fo rm a tio n








goal: e n te r-in fo rm atio n







goal: co m p lete -ca ll




goal: re q u e st-in fo rm atio n








goal: receiv e -in fo rm atio n





thank-custom er

T A O : 'Thank-you'






T A O : hit F4 key

read -scre en (l)


W orkstation : previously displayed source information
T A O : hit F2 key

T A O : hit F3 key
W orkstation : displays credit-card authorization

goal: rele a se -w o rk sta tio n

Figure 11.3 GOMS analysis
(Source: After John, 2003, p. 89, part of Figure 4.9)

Challenge 11.2
Write a GOMS-type description for the simple ATM (Figure 11.2).



11.5 Structural knowledge

4 - Chapter 2 discusses
mental models

Task analysis is about procedures. But before a person sets about some procedure they
need to know what types of things can be accomplished in a domain. For example, if
I am using a drawing package I need to know that there is a facility for changing the
thickness of a line, say, before I set about working out how to do it. I need some concep­
tion of what is possible, or what is likely. So in this section, instead of focusing on the
steps that people have to go through to achieve a goal (hence looking at a procedural
representation), we can look at the structural knowledge that people have and how an
analysis of this can help in designing better systems.
Payne (2012) shows how the concept of a ‘mental model’ can be used to analyse
tasks. He proposes that people need to keep in mind two mental spaces and the rela­
tionships between them. A goal space describes the state of the domain that the person
is seeking to achieve. The device space describes how the technology represents the
goal space. An analysis of the different representations used can highlight where people
have difficulties. If the device space employs concepts that are very different from those

Chapter 11 • Task analysis

that the person uses in the goal space, then translating between them, and explaining
why things happen or why they do not, is made more difficult. A good example of this
is the history mechanism on Web browsers. Different browsers interpret the history in
different ways and some wipe out visits to the same site. If a person tried to retrace
their steps through a Web space, this will not be the same as the steps stored in a history
(Won et al., 2009).
Payne ( 2 0 1 2 ) also discusses the concept of a ‘mental map’, which is analogous to a
real map of some environment and can be used to undertake tasks. He discusses how
an analysis of mental models can be useful in highlighting differences between people’s
views of a system. In one piece of empirical work he looked at different mental models
of an ATM and found several different accounts of where information such as the credit
limit resided.
Green and Benyon (1996) describe a method called ERMIA (entity-relationship
modelling of information artefacts) that enables such discrepancies to be revealed.
ERMIA models structural knowledge and so can be used to represent the concepts that
people have in their minds. Relationships between the entities are annotated with T
or ‘m’, indicating whether an entity instance is associated with one or many instances
of the other entity. Figure 11.4 shows the different beliefs that two subjects had about
ATMs in a study of mental models undertaken by Payne (1991).

S I 5: central machine w ith local ‘dumb’ clients,
nothing on the card except the PIN

Figure 11.4 Comparison of two mental models of ATMs described by Payne (1991)
(Source: After Green and Benyon, 1996)


C h ap ter 25 discusses

m ental maps



Part II • Techniques for designing interactive systems

The designer's model
and system image are
presented in Chapter 3

ERMIA uses an adaptation of entity-relationship modelling to describe structures.
Entities are represented as boxes, relationships by lines, and attributes (the character­
istics of entities) by circles. We introduced E-R modelling in Chapter 9 alongside object
modelling, which is broadly similar.
In Figure 11.5 we can see a typical menu interface. An important part of this type of
analysis is that it helps to expose differences between the designer’s model, the system
image and the ‘user’s’ model. What are the main concepts at the interface?
Menu systems have two main concepts (entities). There are the various menu head­
ings, such as File, Edit and Arrange, and there are the various items that are found
under the headings, such as Save, Open, Cut and Paste. More interestingly, there is a
relationship between the two kinds of entity. Can we imagine an interface that contains
a menu item without a menu heading? No, because there would be no way to get at it.
You have to access menu items through a menu header; every item must be associated
with a heading. On the other hand, we can imagine a menu that contained no items,
particularly while the software is being developed.
This, then, is the basis of ERMIA modelling - looking for entities and relationships
and representing them as diagrams (see Figure 11.6). Benyon et al. (1999) provide a
practical guide to developing ERMIA models, and Green and Benyon (1996) provide
the background and some illustrations. A key feature of ERMIA is that we use the same
notation to represent the conceptual aspects of a domain and the perceptual aspects.
The conceptual aspects concern what people think the structure is and what the
designer thinks the concepts are. The perceptual aspects concern how the structure is
represented perceptually. In the case of menus we have the concepts of menu header
and menu item and we represent these perceptually by the bold typeface and position
on a menu bar and by the drop-down list of items. A different perceptual representation
is to represent the menu using a toolbar.

a list of Menu Headings







graphic objects (the
'handles1show that the
rectangle has been
selected; if a menu
operation, such as
'Rotate', is chosen, that
operation will be applied to
the rectangle)

available under one of
the Menu Headings

Figure 11.5 A simple drawing program, showing the document being created la drawing,
currently consisting of a rectangle and a circle) and the interface to the application

Chapter 11 • Task analysis

Figure 11.6 ERMIA structure of a menu system containing headers and items. The relation­
ship is between reading and item is Tm (that is, each can refer to many items, but an item
can be associated with only one heading). For items, the relationship is mandatory (that is,
every item must have a heading), but a heading can exist with no associated items

Returning to the relationships between menu headers and menu items, each menu
heading can list many items, while each item is normally found under only one heading in other words, the relationship of heading to item is one to many (written l:m).
Is it strictly true that the relationship between menu items and menu headers is 1 :m?
Not quite; by being forced to consider the question precisely, we have been alerted to
the fact that different pieces of software are based on differing interpretations of the
interface guidelines. There is actually nothing to prevent the same menu item being
listed under more than one heading. So an item like ‘Format’ might be found under a
Text heading and also under the Tools heading; the true relationship between heading
and item is therefore many to many, or m:m as it is written.
Many-to-many relationships are inherently complex and can always be simplified by
replacing the relationship with a new entity that has a many-to-one relationship with
each of the original entities. This is a surprisingly powerful analytical tool as it forces the
designer to consider concepts that would otherwise remain hidden.
Look again at the top diagram in Figure 11.4 and consider the m:m relationship
between local machine and card. What is this relationship and does it help us under­
stand anything? The answer is that the relationship represents a transaction: a usage
of a local machine by a card. There is nothing particularly interesting in this except per­
haps that it means that the local machine will not store long-term details of the card but
just deals with transaction details.
ERMIA represents both physical and conceptual aspects of interfaces, which ena­
bles comparisons to be made and evaluations to be carried out. Like GOMS and HTA,
this enables the analyst to undertake model-based evaluation (see Further thoughts).
Because ERMIA presents a clear view of the different models, it can be used as part
of the process of reasoning about the models. If we have a designer’s model that the
designer wishes to reveal, he or she can look at the model of the interface and see to
what extent the ‘intended’ model shows up. Similarly, one can gather different user
views, in the manner of Payne’s work (1991), and compare them to the designer’s view,
making the models and their possible differences explicit through ERMIA.
It has to be said that ERMIA modelling has not been taken up by interaction design­
ers, probably because the effort required to learn and understand it is not repaid by the
insight it provides. Green has continued to work on other ways of bringing this type of
knowledge to HCI through the ‘cognitive dimensions’ framework (Blackwell and Green,
2003) and the CASSM framework (Blandford et a i, 2008).



Part II • Techniques for designing interactive systems

Model-based evaluation

Model-based evaluation looks at a model of some human-computer interaction. It can
be used either with an existing interface or with an envisaged design. It is particularly
useful early in the design process when designs are not advanced enough to be used
by real users or when testing with real users is uneconomic or otherwise infeasible. The
process involves the designer working through a model of a design, looking for poten­
tial problems or areas which might prove difficult. ERMIA can be used like this and
GOMS was used in this way in Section 11.4.
- .............................—

.........................................................- ................................................................................................................................................................................. - ................... —



ERMIA models can be used to explore how people have to navigate through various
information structures in order to retrieve specific pieces of information and even to
estimate the number of steps that people will need to take.

Challenge 11.3

Draw an ERMIA model for the World Wide Web. List the major entities that the Web
has and begin to sketch the relationships. Spend at least 70 minutes on this before
looking at our solution.

11.6 Cognitive work analysis
Cognitive work analysis (CWA) has evolved from the work of Jens Rasmussen and his
colleagues (Rasmussen, 1986, 1990; Vicente and Rasmussen, 1992), originally work­
ing at the Riso National Laboratory in Denmark. Originally formulated to help in the
design of systems concerned with the domain of process control, where the emphasis is
on controlling the physical system behind the human-computer interface, it provides a
different and powerful view on the design of interactive systems. CWA has been used in
the analysis of complex real-time, mission-critical work environments, e.g. power plant
control rooms, aircraft cockpits and so on.
The approach is also known as ‘the Riso genotype’ (Vicente, 1999) and relates closely
to ecological interface design (Vicente and Rasmussen, 1992). Flach (1995) provides a
number of perspectives on the issues and includes chapters by others originating from
the Riso National Laboratory, including Vicente, Rasmussen and Pejtersen. One prin­
ciple underlying CWA is that when designing computer systems or any other ‘cogni­
tive artefact’ we are developing a complete work system, which means that the system
includes people and artefacts. Seeing the whole as a work system enables designers to
recognize that this system is more than the sum of its parts: it has emergent properties.
Another key principle of CWA is that it takes an ecological approach to design. Taking
an ecological approach recognizes that people ‘pick up’ information directly from the
objects in the world and their interaction with them, rather than having to consciously
process some symbolic representation. In CWA, there is much discussion over the simi­
larities between the ecological psychology of Gibson (1986) and designing systems that
afford certain activities. The emphasis is on taking a user-dependent view of the analy­
sis and design, recognizing the skills and knowledge that the user will have.
In the domain in which CWA was formulated, process control, it is vital that the oper­
ator has a correct view of the operation and status of the plant and that he or she can

Chapter 11 • Task analysis

correctly identify any component that is malfunctioning. A key feature of the approach
is to understand the domain-oriented constraints that affect people’s behaviours and to
design the environment so that the system easily reveals the state it is in and how that
state relates to its purpose. CWA provides a structural representation of a domain.
CWA is quite complex and comprises a set of techniques and models. CWA techniques
include such things as task analysis (including sequencing and frequency) and work­
load analysis (flow of work, identification of bottlenecks).
In short, there is a strong emphasis on work analysis and job design.
Modelling in CWA is made up from six different kinds of modelling, each of which
breaks down into further levels. For example, a work domain analysis has five further
levels of abstraction, describing

The functional purpose of the system
The priorities or values of the system
The functions to be carried out by the system
The physical functionality of the system
The physical objects and devices.

The abstraction hierarchy
CWA describes a system, subsystem or component at five levels of abstraction. At the top
level is the system’s purpose: the analysis takes an intentional stance. Taking the design
stance, CWA distinguishes between the abstract function and the generalized function
of the system. The abstract function concerns the capabilities that it must have in order
to achieve its purpose, and the generalized function describes the links between the
physical characteristics and that abstract function. At the physical level of description
CWA distinguishes the physical function from the physical form of the system.
For example, a car’s purpose is to transport people along a road. Therefore it must have
the abstract functions of some form of power, some way of accommodating people and
some form of movement. These abstract functions may be provided by the generalized func­
tions of a petrol engine, some seats and some wheels with pneumatic tyres. Physically the
engine might be realized as an eight-cylinder fuel-injected engine, the seats are of a size to
accommodate people and the tyres have an ability to take the weight of the car and its pas­
sengers. The physical forms of these functions are the features that distinguish one type of
car from another and concern the different arrangements of the engine components, the
colour and material of the seats and the characteristics of the tyres.
A work domain analysis describes the whole system in these terms and describes
each of the subsystems, components and units in these terms. For example, in describ­
ing the car, we could describe each of the engine’s subsystems (fuel system, ignition
system, etc.), its components (the petrol tank, feed tubes, injector mechanism, etc.)
and the basic units that make up the components. At each level of the hierarchy the
connection going up the hierarchy indicates why some system or component exists,
whereas the relationship looking down the hierarchy indicates how something is
achieved. The chain of ‘hows’ describes the means by which something happens and
the chain o f‘whys’ describes the reasons for the design - the ends or teleological analy­
sis. Hence the whole physical functioning of the domain is connected with its purpose.
So, the car can transport people because it has an engine, which is there to provide
the power. The engine needs a fuel system and an ignition system because the fuel sys­
tem and the ignition system provide power. This discussion of means and ends can con­
tinue all the way down to an observer looking under the car bonnet, saying ‘that pipe
takes the fuel from the fuel tank to the fuel injection system but because it is broken this
car has no power so it cannot transport us until it is fixed’.

See also the discussion
o f the dom ain m odel in
Section 17.3



Part II • Techniques for designing interactive systems

CWA in action
Benda and Sanderson (1999) used the first two levels of modelling to investigate the
impact of a new technology and working practice. Their case study concerned an auto­
mated anaesthesia record-keeping system. They undertook a work domain analysis and
an activity analysis in work domain terms.
For the work domain analysis:
• The output was the relationships between purpose, functions and objects.
• Changes representable at this level were changes to the functional structure of this
For the activity analysis in work domain terms:
• The output was the coordination of workflow.
• Changes representable at this level were changes to procedure and coordination.
Based on these analyses, Benda and Sanderson successfully predicted that the introduc­
tion of the automated anaesthesia record-keeping system would take longer to use and
would place additional constraints on the medical team.

Summary and key points



Task analysis is a key technique in interactive system design. The focus may be on the
logical structure of tasks, or the cognitive demands made by tasks procedurally or struc­
turally. Task analysis encompasses task design and it is here that it is probably most use­
ful, as an analysis of a future design is undertaken to reveal difficulties. Task models can
also be used for model-based evaluations.
• Task analysis fits very closely with requirements generation and evaluation methods.
• Task analysis focuses on goals, tasks and actions.
• Task analysis is concerned with the logic, cognition or purpose of tasks.
• A structural analysis of a domain and worksystem looks at the components of a sys­
tem and how the components are related to one another.

E x e rc is e s
1 Undertake an HTA-style analysis for phoning a friend of yours whose number
you have in the phone's address book. Of course the actual actions will be
different for different phones. If you can, compare your solution to someone
else's. Or try it with two different phones.

2 Now translate the HTA into a GOMS analysis. What different insights into the
task does this give you?

Further reading
Annett, J. (2004) Hierarchical task analysis. In Diaper, D. and Stanton, N. (eds), The Handbook
of Task Analysis for Human-Computer Interaction. Lawrence Erlbaum Associates, Mahwah, NJ.
Green, T.R.G. and Benyon, D.R. (1996) The skull beneath the skin: entity-relationship model­
ling of information artefacts. InternationalJournal of Human-Computer Studies, 44(6), 801 -28.

Chapter 11

John, B. (2003) Information processing and skilled behaviour. In Carroll, J.M. (ed.),


M o d e ls, T h e o rie s a n d F ra m e w o rk s. Morgan Kaufmann, San Francisco, CA. T h is p ro v id e s a n
e x c e lle n t d isc u ssio n o f G O M S .

Getting ahead
Carroll, J.M. (ed.) (2003)

H C I M o d e ls , T h e o rie s a n d F r a m e w o rk s . Morgan Kaufm ann, San

Francisco, CA. T h is is a n e x c e lle n t in tro d u c tio n to m a n y o f th e k e y ta s k a n a ly s is m e th o d s a n d
in c lu d e s a c h a p t e r b y S te v e P a y n e , 'U se rs' m e n ta l m o d e ls : th e v e ry id e a s', a g o o d c h a p te r o n c o g ­
n itiv e w o rk a n a ly s is b y P e n e lo p e S a n d e rs o n , a n d th e c h a p t e r b y B o n n ie J o h n o n G O M S .

Diaper, D. and Stanton, N. (eds) (2004) The Handbook of Task Analysis for HumanComputer Interaction. Lawrence Erlbaum Associates, Mahwah, NJ. A very comprehensive
coverage of task analysis with chapters from all the major writers on the subject. There is a good
in tr o d u c to r y c h a p t e r b y D ia p e r a n d tw o g o o d c o n c lu d in g c h a p te rs b y th e e d ito rs.

The website for cognitive dimensions work:
The accom panying website has links to relevant websites. Go to
w w w .p e a r s o n e d .c o .u k / b e n y o n

Comments on challenges
Challenge 11.1
The overall goal of this activity is to have the PVR record a TV programme. This will involve the
following tasks: (1) making sure the PVR is ready to record, (2) programming the right TV channel,
(3) programming the right time to start and stop the recording, and (4) setting the PVR to automati­
cally record. Task 1 will involve the following subtasks: (1.1) finding the right remote control for the
PVR, (1.2) ensuring the TV is using the PVR, and (1.3) selecting the appropriate channel. Task 1.1
will involve all manner of considerations such as whether the remote is down the back of the sofa,
how many other remote controls are on the coffee table and how long ago you last recorded a pro­
gramme. For someone familiar with the household this might be a simple action, but for someone
unfamiliar with the whole set-up, it can be a major task.

Challenge 11.2
G O M S goal h ie ra rc h y

O b se rve d b e h a vio u r

Goal: present personal ID
Goal: insert card
Goal: locate slot

Card inserted
Screen displays 'enter PIN'

Goal: enter PIN
Recall number
Locate number on keypad

Press key
Beep +*

Repeat 4 times

Task analysis



Part II • Techniques for designing interactive systems

Challenge 11.3
The major entities you should have thought of are Web pages and links. Then there are websites.
There are many other things on the Web; files are one type of thing, or you may have thought of dif­
ferent types of file such as PDF files, Word files, GIFs, JPEGs and so on. Overall, though, the Web has
quite a simple structure, at least to start with. A website has many pages, but a page belongs to just
one site. A page has many links, but a link relates to just one page. This is summarized in Figure 11.7.

Figure 11.7
As soon as we have this basic structure we start questioning it. What about 'mirror' sites? A link can
point to a whole website, so we should include that in our model. How are we defining a page? Or
a site? This will affect how we model things. What about within-page links? And so on.

Chapter 12
Visual interface design





Introduction 256


Graphical user interfaces 257

The design of the interface that mediates the interaction of people
with devices is a crucial characteristic of the overall interaction design.
This is often referred to as the user interface (Ul) and it consists of
everything in the system that people come into contact with, whether
that is physically, perceptually or conceptually. In this chapter we
discuss the issues of interface design focusing on the visual aspects
of the design. In the next chapter we focus on issues of design when
multiple modalities are involved in an interface.


Interface design
guidelines 263


Psychological principles and
interface design 270


Inform ation design 279

12.6 Visualization 282
Sum m ary and key points 286

After studying this chapter you should be able to:

Exercises 286
Further reading 286
Web links 287
Com m ents on challenges 287

• Understand different types of interaction, command languages and
graphical user interfaces (GUIs)
• Understand and apply interface design guidelines
• Understand the issues of information presentation and visualization.

2 56

Part II • Techniques for designing interactive systems

12.1 Introduction

♦- We first encountered the
interface in Chapter 2

The design of the interface that mediates the interaction of people with devices is a cru­
cial characteristic of the overall interaction design. This is often referred to as the user
interface (UI) and it consists of everything in the system that people come into contact
with, whether that is physically, perceptually or conceptually.
Physically people interact with systems in many different ways, such as by pressing
buttons, touching a screen, moving a mouse over a table so that it moves a cursor over
the screen, clicking a mouse button, rolling their thumb over a scroll wheel. We also
interact physically through other senses, notably sound and touch, but we defer a dis­
cussion of these modalities until the next chapter.
Perceptually people interact with a system through what they can see, hear and
touch. The visual aspects of interface design concern designing so that people will see
and notice things on a screen. Buttons need to be big enough to see and they need to
be labelled in a way that is understandable for people. Instructions need to be given so
people know what they are expected to do. Displays of large amounts of information
need to be carefully considered so that people can see the relationships between data to
understand its significance.
Conceptually people interact with systems and devices through knowing what they
can do and knowing how they can do it. Conceptually people employ a ‘mental model’
of what the device is and how it works. People need to know that certain commands
exist that will allow them to do things. They need to know that certain data is available
and the form that that data takes. They need to find their way to particular pieces of
information (undertake navigation). They need to be able to find details of things, see
an overview of things and focus on particular areas.
Putting these three aspects together is the skill of the interface designer. Interface
design is about creating an experience that enables people to make the best use of the
system being designed. When first using a system people may well think ‘right, I need to
do X so I am going to use this device which means I am going to have to press Y on this
keyboard and then press Z’, but very soon people will form their intentions in the con­
text of knowing what the system or device does and how they can achieve their goals.
Physical, perceptual and conceptual design get woven together into the experiences of
The vast majority of personal computers, phones and handheld and tablet devices
have graphical user interfaces (GUIs) typically based on one of the main three soft­
ware platforms: Apple (with its operating systems OS X and iOS), Microsoft Windows
and Google’s Android. However, underlying these GUIs are user interfaces without the
graphical elements, known as command languages.
A command language is simply a set of words with an associated syntax, the rules
governing the structure of how commands are put together. To interact with a device
using a command language the user types a command such as ‘send’, ‘print’, etc., and
supplies any necessary data such as the name of a file to be sent or printed. UNIX is the
most common command language. Command languages suffer from the problem that
• Have to recall the name of a particular command from the range of literally hundreds
of possibilities
• Have to recall the syntax of the command.
Prior to the creation of Microsoft Windows, the vast majority of personal computers
ran the operating system MSDOS. On switching on their PC, people were faced with the

Chapter 12 • Visual interface design


Command Prompt

. □

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8 , 6 8 7 , 4 8 4 ,928 b y t e s f r e e

^ IC :\>

Figure 12.1 The enigmatic c:\> prompt in MSDOS

user interface known as the c:\> prompt (Figure 12.1). People were then required to type
in a command such as dir which listed the contents of the current directory (or folder).
Anyone who had never encountered MSDOS (or even those who had) was continually
faced with the problem of having to recall the name of the command to issue next.
However, command languages are not all bad. They are quick to execute and, par­
ticularly if there are only a few of them, people using them frequently will remember
them. Commands can be spoken which makes for a very convenient interface, particu­
larly if you are concentrating on something else. Spoken commands are very convenient
for in-car systems, for example. The search engine Google has a number of commands
such as ‘define:’ to indicate particular types of search. There are gestural commands
such as a three-fingured swipe on an Apple track pad to move to the next item.

Challenge 12.1
In his piece in Interactions Don Norman (2007) argues that commands have a number
of benefits. However, a key issue is that the system must be in the correct mode to
recognize and react to the commands. For example, in Star Trek people have to alert the
computer when they wish to enter a command, e.g. the captain might say 'Computer.
Locate Commander Geordie Laforge'. If they did not do this the computer would not be
able to distinguish commands intended for it from other pieces of conversation. However,
in the 'Turbo Lift’ (the elevator), this is not necessary. Why is this?

12.2 Graphical user interfaces
Graphical user interfaces (GUIs), which are found on every personal computer, on smart
phones, on touchscreen displays and so on, have had an interesting though brief history.
The Microsoft range of Windows GUIs were broadly based on (perhaps influenced by
might be better) the Macintosh, which in turn was inspired by work at Xerox PARC,
which in turn was developed and built upon early research at the Stanford Research
Laboratory and at the Massachusetts Institute of Technology. During the 1980s and
1990s a number of different designs of GUIs were produced, but gradually Windows




Techniques for designing interactive systems

and Apple Macintosh came to dominate the GUI operating system market. However,
Google Chrome OS may be just starting to challenge them.
A direct manipulation (DM) interface is one where objects - usually graphical objects
on a screen - are directly manipulated with a pointing device in place of the typed com­
mands of command languages. Ben Shneiderman at the University of Maryland coined
the term ‘direct manipulation’ in 1982. He defined a DM interface as one where there is:
1 Continuous representation of the object of interest.
2 Physical actions or labelled button presses instead of complex syntax.
3 Rapid incremental reversible operations whose impact on the object of interest is
immediately visible. (Shneiderman, 1982, p. 251)
The fact that objects are represented as graphics means that people can recognize
what they want to do rather than having to recall some command from memory. They
can also reverse their actions, which means recovering from mistakes is much easier.

The most prevalent of the GUIs is the WIMP interface such as Windows or OS X. WIMP
stands for windows, icons, menus and pointers. A window is a means of sharing a device’s
graphical display resources among multiple applications at the same time. An icon is an
image or symbol used to represent a file, folder, application or device, such as a printer.
David Canfield Smith is usually credited with coining the term in the context of user inter­
faces in 1975, while he worked at Xerox. According to Smith, he adopted the term from
the Russian Orthodox Church where an icon is a religious image. A menu is a list of com­
mands or options from which one can choose. The last component is a pointing device
of which the mouse is the most widespread, but fingers are also used, as is the stylus. An
important aspect of a WIMP environment is the manner in which we use it. This form of
interaction is called direct manipulation because we directly manipulate the on-screen
objects as opposed to issuing commands through a command-based interface.

Direct manipulation
A direct m anipulation (D M ) interface is one w here graphical objects on the screen are
directly manipulated w ith a pointing device. This approach to interaction was first dem ­
onstrated by Ivan Sutherland in the Sketchpad system. T he concept o f direct m anipula­
tion interfaces for everyone w as envisioned by Alan Kay o f Xerox PARC in a 1977 article
about the Dynabook (Kay and Goldberg, 1977). The first com m ercial systems to make
extensive use of direct m anipulation w ere the Xerox Star (1981), the Apple Lisa (1982)
and M acintosh (1984). However, it was Ben Shneiderm an at the University o f M aryland
w ho actually coined the term 'direct manipulation' in 1982.
Direct m anipulation depends upon having bitmapped screens, so that each picture
elem ent or pixel can be used for input and output, and a pointing device. Early mobile
phones did not have such a display, so direct m anipulation o f objects w as not possible.
Nowadays m any o f them do, and DM is found on a w id e range o f devices.





Windows allow a workstation’s screen to be divided into areas which act like separate
input and output channels that can be placed under the control of different applica­
tions. This allows people to see the output of several processes at the same time and to
choose which one will receive input by selecting its window, using a pointing device,

Chapter 12 • Visual interface design


such as clicking on it with a mouse, or touching a touchscreen. This is referred to as
changing the focus. Early windowing systems were tiled (did not overlap), but over­
lapping windows were eventually suggested by Alan Kay at Xerox PARC (although MS
Windows 1, which was released in 1985, supported only tiled windows).
Windowing systems exist in a wide variety of forms but are largely variations on the
same basic theme. Microsoft Windows dominates the personal computer market and in
turn exists in a variety of forms, although they appear to be converging (at least in terms
of appearance) in an XP-like form. There are two other major windowing systems which
are widely used. The current Macintosh OS X is proving to be well received (particularly
by academics); the X Window System was originally developed at MIT. X is used on many
UNIX systems and X11R6 (version 11, release 6) was originally released in May 1994.
X is large and powerful and, above all, complex. Figures 12.2 and 12.3 show examples of
an OS X window and a Microsoft Windows 7 window.

Interactive window

$«4«t wh*t you *»nt to (hve
_/ Pictures

V Documents

y ) Music

V Printers

J Videos

Figure 12.2 OS X window

Figure 12.3 Windows 7 window

Icons are used to represent features and functions on everything from software applica­
tions, DVD players and public information kiosks to clothing (as those incomprehensible
washing symbols on the back of the label). Icons are generally regarded as being useful
in helping people to recognize which feature they need to access. Icons first appeared
on the Xerox Star (Box 12.2) and became an important research issue in the 1980s and
early 1990s, though since then there has been considerably less interest.
The use of icons is now ubiquitous, but their design, apart from a small number of
standard items (see Further reading at the end of this chapter) is rather arbitrary. Icons
make use of three principal types of representation: metaphor, direct mapping and
convention. Metaphor relies on people transferring knowledge from one domain and
applying it to another. The use of metaphor can be seen in icons for such things as the
cut and paste operations that exist in many applications. These two operations relate to
a time when in preparing a text it was not unusual to cut out elements of a document
using scissors and then physically paste them into another document.
The use of direct mapping is probably the simplest technique in the design of icons
and involves creating a more or less direct image of what the icon is intended to rep­
resent. Thus a printer icon looks like a printer. Finally, convention refers to a more
or less arbitrary design of an icon in the first instance, which has become accepted as
standing for what is intended over time. This can lead to anachronisms. For example,
the icon representing the function save on the Mac that I am using to write this is a

M etaphor is discussed in

detail in Chapter 9


Part II • Techniques for designing interactive systems

representation of a floppy disk (Figure 12.4) despite the fact that the machine is not
fitted with a floppy disk drive and many people will never have heard of a floppy disk.
Figure 12.5 shows further examples of icons.

500 GB
5ATA Disk
Figure 12.4 An icon representing a floppy disk

Figure 12.5 Examples of commonly used icons

(Source: Ivary/Getty Images)

The Xerox Star
It is widely recognized that every graphical user interface owes a debt to the Xerox
Star workstation. Launched as the 8010 Star information system in April 1981, it was
designed to be used by office workers and other professionals to create and manage
business documents such as memos, reports and presentations. The Star's designers took
the perspective that people were primarily interested in their jobs and not in computers
per se. Thus from its inception a central design goal was to make use of representations
of objects that would be easily recognizable from an office environment (Figure 12.6).

Figure 12.6
The Xerox Star user
(Source: Courtesy of Xerox Ltd)



However, the two most important design issues for icons are legibility (whether or
not one can discriminate between icons) and interpretation (what it is that the icon is
intended to convey). The legibility aspect refers to icons not always being viewed under
ideal conditions (e.g. poor lighting, screen resolution or the size of the icon itself).
Research has indicated that under such conditions it is the overall global appearance

Chapter 12 • Visual interface design

of the icon that aids discrimination, so icons should not be designed so that they differ
only with respect to one small detail.
The interpretation of the icon is a non-trivial issue. The icon may indeed be recog­
nized as an object but remains opaque as to its meaning. Brems and Whitten (1987)
for this reason caution against the use of icons which are not accompanied by a textual
label. Do remember, however, that one reason why icons are used is that they are suc­
cinct and small (i.e. do not take up too much screen space); adding labels removes this
advantage. Solutions to this problem include balloon help and tool tips which have
appeared as effective pop-up labels.

Horton’s icon checklist
William Horton (of William Horton Consulting, Inc.) has produced a detailed checklist
(1991) designed to help the icon designer avoid a whole raft of common mistakes. We
reproduce his top-level headings here together with a sample question for each issue.


Does the image spontaneously suggest the intended concept to the viewer?


Are the objects in the icon ones familiar to the user?


Are additional cues (label, other icon documentation) available to
resolve any ambiguity?

M em orable

Where possible, does the icon feature concrete objects in action? Are
actions shown as operations on concrete objects?

Inform ative

Why is the concept important?


Is the number of arbitrary symbols less than 20?


Is every icon distinct from all others?


Does the image use smooth edges and lines?


Have you tested all combinations of colour and size in which the icon
will be displayed?

Com pact

Is every object, every line, every pixel in the icon necessary?


Is it clear where one icon ends and another begins?


Can I draw the image smaller? Will people still recognize it?

Many applications of interactive systems make use of menus to organize and store the
commands that are available. These are often called menu-driven interfaces. Items are
chosen from the menu by highlighting them, followed by pressing < Return > or by sim­
ply pointing to the item with a mouse and clicking one of the mouse buttons. Menus are
also familiar on mobile phones, touchscreen kiosks and, of course, restaurants where
the available options for the customer are listed on a menu.
When creating menus, commands should be grouped into menu topics, which are a
list of menu items. When a command or option (menu item) is selected from the list, an
action is performed. Menus are also used extensively on websites to structure informa­
tion and to provide the main method of navigation of the site’s content. While menus
should be simple, there is little to prevent the over-zealous designer from creating very
complex and difficult to navigate menus. Figure 12.7 is a screenshot of the Mac ver­
sion of a typical hierarchically organized menu. In this example, the various options
are arranged under a top-level topic (filter) and in turn have series of sub-menus.
Figure 12.8 is the equivalent Windows XP version. Hierarchical menus are also called


Part II • Techniques tor designing interactive systems

F ig u r e 12.7 An example of a menu taken from the Mac
version of Adobe® Photoshop®

F ig u r e 1 2 .8

The jump bar menu from Windows 8

cascading menus. In a cascading menu, the sub-menu appears to cascade out when a
choice is made from the higher-level menu.
Another frequently encountered form of menu is the pop-up. A pop-up menu is
distinguished from a standard menu in that it is not attached to a menu bar in a fixed
location (hence the name). Once a selection is made from a pop-up menu, the menu
usually disappears. Figure 12.9 is a screenshot of a pop-up menu. In this case it includes
a number of options that are not simple commands, so it is more usually referred to as a

8 0 0 ,.L i chapters S A 6 *03 Info
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chapters 5 ft 6 v03
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Sharing A Permissions:

F ig u r e 12.9 A screenshot of a pop-up menu (or panel) providing information on the file
'chapters 5 & 6 v03' after clicking on the file and using the context menu

Chapter 12 • Visual interface design

panel. Also, in this case it is also a contextual menu. The make-up of contextual menus
varies according to the context (hence their name) from which they are invoked. If a file
is selected, the contextual menu offers file options. If instead a folder is selected, folder
options are displayed.
Finally, to aid experts, it is common practice to associate the most frequently used
items with keyboard shortcuts (also known as accelerators in MS Windows systems).
Figures 12.10 and 12.11 illustrate shortcuts for both the Windows XP operating system
and OS X.

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Can't Repeat

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F ig u r e 12.10

Shortcuts (Windows XP)

F ig u r e 12.11

Shortcuts (OS X)

The final part of the WIMP interface is the pointer. These come in many forms, some of
which are discussed below. The most common is the mouse, but joysticks are also com­
mon, for example in game controllers. On mobile phones and tablets, a stylus is often
provided as the pointer and on touchscreen systems the finger is used. Remote pointers
include the Wii wand and other infra-red pointers, for example for doing presentations.
The arrival of multi-touch surfaces has enabled a wide range of gestures to be recog­
nized in addition to a simple point and select operation.

12.3 Interface design guidelines
Modern graphical user interfaces have as part of their make-up a range of widgets
including buttons and radio buttons, sliders, scroll bars and checkboxes. These will
often combine several aspects of the basic WIMP objects. Designing a GUI for an appli­
cation does not guarantee that the finished system will be usable. Indeed, given the
ease with which GUIs can be created with modern development tools, it is now very
simple to create inelegant, unusable interfaces. This problem is well recognized and has
resulted in the creation of style guides that provide a range of advice to the interface

Gestures are discussed in
Chapter 13



Part II • Techniques for designing interactive systems

developer. Style guides exist for the different kinds of windowing systems available and
are occasionally written by specific software vendors or companies to ensure that their
products are consistent, usable and distinctive.
The Microsoft website offers abundant helpful advice on designing interfaces. Here
is a sample:
Grouping of elements and controls is also important. Try to group information logically
according to function or relationship. Because their functions are related, buttons for navi­
gating a database should be grouped together visually rather than scattered throughout a
form. The same applies to information: fields for name and address are generally grouped
together, as they are closely related. In many cases, you can use frame controls to help
reinforce the relationships between controls.

Other advice on interface design operates at a much smaller level of detail, at the
level of individual widgets. Interface consistency is an important result of using style
guides as is evident on devices such as the iPhone.
The Apple guidelines for the iOS platform provide good advice and guidance on
designing for standard items such as a toolbar, navigation bar, etc. See Box 12.3.

The Apple toolbar
A toolbar (Figure 12.12) contains controls that perform actions related to objects in
the screen or view. A toolbar is typically contained in a navigation controller, which
is an object that manages the display of a hierarchy of custom views. To learn more
about defining a toolbar in your code, see "Displaying a Navigation Toolbar" in View
Controller Programming Guide for iOS and UlToolbar Class Reference.


4 of 15

it> ©


Figure 12.12 Apple toolbar
A p p e a r a n c e a n d b e h a v io r

On iPhone, a toolbar always appears at the bottom edge of a screen or view, but on
iPad it can instead appear at the top edge.
Toolbar items are displayed equally spaced across the width of the toolbar. The pre­
cise set of toolbar items can change from view to view, because the items are always
specific to the context of the current view.
On iPhone, changing the device orientation from portrait to landscape can change
the height of the toolbar automatically. On iPad, the height and translucency of a tool­
bar does not change with rotation.



G u id e lin e s

Use a toolbar to provide a set of actions users can take in the current context.
• Use a toolbar to give people a selection of frequently used commands that make
sense in the current context. An alternative is to put a segmented control in a toolbar


— „ ........- .................................... -

_ _______________________ ___ ______ i

Chapter 12 • Visual interface design







to give people access to different perspectives on your application's data or to differ­
ent application modes (for usage guidelines, see "Segmented Control").
If appropriate, customize the appearance of a toolbar. If you want the toolbar to
coordinate with the overall look of your app, you can specify a custom background
image or tint and you can specify translucency. In some cases, it can be a good idea
to supply a resizable background image; to learn more about creating a resizable
image, see "Tips for Creating Resizable Images."
Make sure that your toolbar customization is consistent with the look of the rest
of your application. If you use a translucent toolbar, for example, don't combine it
with an opaque navigation bar. Also, it's usually best to avoid changing the appear­
ance of the toolbar in different screens in the same orientation.
Note: If you want to design a toolbar that slightly overlaps the main content view,
you can supply a custom background image that is taller than the standard bar
height. In an iPhone app, you can supply different background images for the differ­
ent bar heights (in an iPad app, the same custom image is used in both orientations).
If you provide a taller background image, it's best to create a translucent image (and
to specify that the toolbar itself is translucent) so that users can see the content
behind the bar.
Maintain a hit target area of at least 44X44 points for each toolbar item. If you crowd
toolbar items too closely together, people have difficulty tapping the one they want.
Use system-provided toolbar items according to their documented meaning.
See "Standard Buttons for Use in Toolbars and Navigation Bars" for more informa­
tion. If you decide to create your own toolbar items, see "Icons for Navigation Bars,
Toolbars, and Tab Bars" for advice on how to design them.
If appropriate, customize the appearance of toolbar items. If you customize the
appearance of the toolbar, you might want to consider creating a coordinating
appearance for the toolbar items. You might also want to adjust the selected appear­
ance of the items so that they look good on your customized toolbar background.
Try to avoid mixing plain style (borderless) and bordered toolbar items in the same
toolbar. You can use either style in a toolbar, but mixing them does not usually look
On iPhone, take into account the automatic change in toolbar height that occurs
on device rotation. In particular, make sure your custom toolbar icons fit well in
the thinner bar that appears in landscape orientation. Don't specify the height of a
toolbar programmatically; instead, you can take advantage of the UIBarMetrics con­
stants to ensure that your content fits well. . .


Other advice on interface design operates at a much smaller level of detail, at the level
of individual widgets. For example Android provide detail advice about how large to
make certain widgets and Apple say that any button should be no smaller than 44 pixels
square. Android widgets are shown in Figure 12.13.
Radio buttons
Use a series of radio buttons to allow people to make exclusive choices - think
about the buttons on a radio: you can listen to FM or AM at any one time but not
both. Figure 12.14 is a detail from a Photoshop interface dialogue in which the
radio buttons constrain people to choosing a Selection or Image. These choices are




Techniques for designing interactive systems



me, John 2


Happy birthday! - Thanks'

Mary, me 2


Don’t forget! - Yes, thanks for reminding
me. Tak soon.

The Emperor


Battlestation plans - Make sure to plug
that hole we talked about

Figure 12.13 Android widgets

Figure 12.14 Radio buttons
and check boxes from
Adobe® Photoshop® from
Apple OS X

Checkboxes should be used to display individual settings that can be switched (checked)
on and off. Use a group of checkboxes for settings that are not mutually exclusive (that
is, you can check more than one box). An example is shown in Figure 12.15.

G e n e ra l o p tio n s


A lw a y s s u g g e s t r e p la c e m e n ts fo r m issp e lled w o rd s

f"~ A lw a y s c h e c k sp e llin g b e fo r e s e n d in g

Ig n o re w o rd s in U P P E R C A S E

l~” Ig n o re w o rd s w ith n u m b ers


Ig n o re orig in a l m e ss a g e t e x t in re p ly o r fo rw a rd

Figure 12.15 A checkbox
from MS Outlook from
Windows XP

Chapter 12

Visual interface design

Challenge 12.2
You are designing an e-mail client which - among other things - allows people to:
• Set a series of preferences for incoming mail (download large files on receipt,
display first two lines of message body, reject mail from senders not in address
book, alert when new mail received . . . )
• Set a colour scheme for the e-mail application (hot colours, water colours or jewel
W ould you use radio buttons o r checkboxes fo r these?


A toolbar is a collection of buttons grouped according to function (in this respect they
are conceptually identical to menus). The buttons are represented as icons to give a
clue as to their function. Passing the mouse pointer over an icon will usually trigger
the associated ‘tool tip’, which is a short textual label describing the function of the
button. Toolbars are also configurable: their contents can be changed and one can
choose whether or not they are displayed. Hiding toolbars helps make the best use of
the display resources (usually described as the screen real-estate). Figure 12.16 illus­
trates this.

Figure 12.16 Why it is useful to be able to hide the full range of available toolbars (taken
from MS PowerPoint!

List boxes
A list box is an accurately named widget as it is a box in which files and options are
listed. List boxes take a variety of forms and within these forms they offer differ­
ent ways of viewing the contents - as lists (with more or less detail), as icons or as
thumbnails (little pictures of the files’ contents). A list box for the iPhone is shown in
Figure 12.17.




Techniques for designing interactive systems

Fig u re 12.17 iPhone list box
(Source: © B. O'Kane/Alamy Images)

A slider is a widget that can return analogue values: rather than setting, say, the vol­
ume to 7 on a scale of 10, people can drag a slider to a position three-quarters of the
way along a scale. Sliders (Figure 12.18) are ideally suited to controlling or setting such
things as volume or brightness or scrolling through a document.

Figure 12.18 The RealOne
Player® with two slider
(Source: Courtesy of Real
Networks, Inc.)

Form fill
Form filling is an interface style that is particularly popular with Web applications. Form
fill interfaces are used to gather information such as name and address. Figure 12.19 is
a very typical example of a form fill interface. This screenshot is taken from an on-line
bookshop. The individual boxes are called fields and are frequently marked with an
asterisk (*) to indicate that an entry is m andatory. This particular interface is a hybrid
as it not only has form fill aspects but has other widgets too, including pull-down menus.

Chapter 12 • Visual interface design


Form fill interfaces are best used when structured information is required. They can
sometimes be automatically updated from a set of structured data stored on a personal
computer. Examples of structured information include such things as:
• An individual’s name and postal address required for mail order services
• Travel details, e.g. the airport from which one is flying, intended destination, time
and date of departure
• Number and type of goods, e.g. 10 copies of the DVD The Sound of Music.

Wizard is the name given to a style of interaction that leads people by the metaphorical
hand (or pointer) step-by-step through a series of questions and answers, picklists and
other kinds of widgets to achieve a task. In MS Windows wizards are used to install hard­
ware and applications. This style of interaction is widely used by all windowing systems.
The great strength of wizards is that they present complex tasks in ‘bite-sized’ pieces.
Figure 12.20 is a series of screenshots capturing the steps involved in installing a new
item of hardware. This is only one possible route through the process of installing a
new item of hardware. Many others are possible.

Figure 12.21 illustrates two different approaches (by the same software vendor) to alert­
ing people to the presence of new mail. Figure 12.21(a) is the unobtrusive display of an
envelope or mailbox symbol. In this instance one would expect the user to notice the mes­
sage but in their own time. The second approach, in contrast, may interrupt people’s work,
so do not display this kind of alert box, which requires interaction, unless it is important,
urgent or life-threatening. Allow the person to configure the application to turn off such
alerts. Figure 12.21 (b) is an illustration of an unobtrusive alert signalling the delivery of
a new e-mail message.



Part II • Techniques for designing interactive systems

Add Hardware Wizard

Add Hardware Wizard

W elcome to the Add Hardware Wizard

Is the hardware connected?

This wcatd helps you;
• In s ta l so ftw are to support the hardw are yo u add to y o u
com puter
• T roubieshoot problem s yo u may be having w ith y o u
hardw are


H a ve yo u alread y co nnected th is hardw are to y o u com puter?

O N o . I h ave not added the hardw are yet

If your hardware came with an installation CD.
it is recommended that you click Cancel to
close this wizard and use the manufacturer's
CD to install this hardware.

T o co ntinue, d ic k N ext.

Step 2

Step 1

Figure 12.20 The Microsoft Add Hardware wizard

Chapter 21 discusses

Attracting attention is a simple enough matter - flash a light, use some other form
of animation, ring a bell, and our attention is directed at that stimulus. It is, of course,
possible to alert someone as to where to direct their attention. An air traffic controller’s
attention, for example, might be directed to a potential collision.
However, the challenge of attracting and holding attention is to do so in a manner which:
• Does not distract us from the main task, particularly if we are doing something
important, such as flying an aircraft or operating a complex or hazardous tool
• In certain circumstances can be ignored while in other circumstances cannot and
should not be ignored
• Does not overwhelm the user of a system with more information than they can rea­
sonably understand or respond to.
r ............................................ .................... -...........

. ...........


. '■

12.4 Psychological principles and interface design
As we mentioned above, there are many sites offering good guidelines to the interface
designer. Apple, Android and Microsoft have style guides and many development envi­
ronments will ensure that designs conform to the standards they are aiming at. There
are also many issues applicable to the different contexts of design - websites, mobiles,
etc. - that we discuss in Part III. In this section we present some guidelines deriving
from the principles of psychology presented in Part IV.
Cooper et al. (2007) argues that visual interface design is a central component of
interaction design as it combines graphic design, industrial design and visual infor­
mation design. We deal with information design and the closely related area of

Chapter 12 • Visual interface design

visualizations in the next section. Designers need to know about graphic design, such
as what shape, size, colour, orientation and texture screen objects should be. Designs
should have a clear and consistent style. Recall the idea of a design language introduced
in Chapter 3 and discussed in Chapter 9. The design language will be learnt and adopted
by people, so they will expect things that look the same to behave the same and, con­
versely, if things behave differently make sure they look different. Cooper recommends
developing a grid system to help to structure and group objects at the interface. In
Chapters 8 and 14 we describe wireframes which are used to provide visual structure.
However, we cannot hope to teach the whole of graphic design and pointers are given
in the Further reading section to comprehensive texts on this. We can, however, provide
some guidelines that follow from our understanding of the psychology of people.

Guidelines from perception
Chapter 25 discusses perception and introduces a number of ‘laws’ of perception that
have been developed by the ‘gestalt’ school of perception. Perception research also pro­
vides us with other fundamental aspects of people’s abilities that should be considered
when designing visual interfaces.
Using proximity to organize buttons
One of the Gestalt principles of perception is the observation that objects appearing close
together in space or time tend to be perceived together. The usefulness of this law can be
seen by contrasting the next two figures. Figure 12.22 is a standard Microsoft Windows XP
alert box with the buttons equally spaced. Figure 12.23 is the OS X equivalent. The Mac
version makes clear use of proximity. The Cancel and Save buttons are grouped away from
the option Don’t Save. This has the effect of seeing the two commands - Save and Cancel
- as a pair and clearly separating from the potentially ambiguous Don’t Save.

Figure 12.22

Equally spaced

buttons - W indows XP




Do you want to save the changes you made to
CVE Evaluation.docx?

Don't Save

Figure 12.23




Buttons organized by proximity - OS X

Using similarity to organize files
A second Gestalt law we consider is that of similarity. Figure 12.24 is a screenshot of
the contents of a folder. All of the files are ordered alphabetically, starting at the top left.



Part II • Techniques for designing interactive systems


0 1 - context & design

02 - data gathering
rich pics

06 - cultural m odels








1p n

' pn




0 7 - consolidation (part







d *)


m oviedyna...



p sn

10 - design 2.ppt


11 - from design to roll

Figure 12.24 Organizing files using similarity


Figure 12.25 Disorganized files

The PowerPoint files are perceived as a contiguous block. This stands in sharp contrast
to the file icons in Figure 12.25.
Using continuity to connect disconnected elements
A third Gestalt law is continuity. Disconnected elements are often seen to be part of a
continuous whole. Figure 12.26 illustrates part of an MS Windows scrollbar that indi­
cates that there is more of the document to be seen below the current windowful. The
length of the slider is an indication of how much of the total document is visible. The
slider indicates that about 80 per cent of the document is visible.






This particular law refers to the fact that it has been found that closed objects are eas­
ier to perceive than those that are open. As evidence of this, we will often unconsciously
add missing information to close a figure so that it is more easily perceived against its
An example of the use of closure is the Finder application (Figure 12.27) which
offers a visual track from the top level of a computer’s hard disk (down) to an individual
file. We perceive a connection running from My hard disk on the far left to the file MS
Scrollbar on the extreme right, yet the connection is not strictly continuous.

Principles from memory and attention
mA ,

Our understanding of human abilities in remembering and attending to things also
leads to a number of sound guidelines. Memory is usually considered in terms of our

Fig u re 12.26
A Microsoft
W indows XP

Fig u re 12.27 The new Finder w indo w (OS X)

Chapter 12 • Visual interface design

short-term or working memory and long-term memory. These are explained in detail in
Chapter 21. Attention concerns what we focus upon.

Short-term (or working) memory
There is a widely quoted design guideline based on Miller and his magic number. George
Miller (1956) found that short-term memory is limited to only 7 ± 2 ‘chunks’ of informa­
tion. This principle has been used in HCI to suggest that menus should be restricted to
about seven items, or Web navigation bars should be seven items. While these are per­
fectly reasonable heuristics for designers to use, they do not derive from a limitation of
short-term memory which is to do with how much most people can remember.
There is also an issue about how true this finding is, and more recent work indicates
that the real capacity of working memory is closer to three or four items; indeed, Cowan
has argued for 4 ± 1 (Cowan, 2002). The central observation, however, that you should
not expect people to remember lots of detail is well made.

Chunking is the process of grouping information into larger, more meaningful units,
thus minimizing the demands on working memory. Chunking is a very effective way of
reducing memory load.
An example of chunking at the interface is the grouping of meaningful elements of a
task into one place (or dialogue). Think about setting up a standard template for a docu­
ment. Among the things we have to remember to do are printing the document on the
printer we wish to use, setting document parameters such as its size and orientation, set­
ting the print quality or colour setting, and so on. Another example of chunking can be
seen in Figure 12.28. Here a large number of formatting options (font, alignment, border
and document setting) have been chunked into a single, expandable dialogue. The ►sym­
bol indicates that the selection will expand if selected. Having clicked on the Alignment
and Spacing button, the chunked dialogue expands to unpack a number of related options.

0 O Q

Q~j Wallpapers Info_____________

W allpapers

2 5 .3 MB

i—»— * Modified: 7 February 2013 11:43
r S potlight C om m ents:

§ 0 9

( "i Wallpapers Info____________

W allpap ers

2 5 .3 MB

fa----- i Modified: 7 February 2013 11:43

▼ General:
Kind: Folder
Size: 25.290.993 bytes (25.3 MB on
disk) for 31 items
Where: /Users/Nick_Riley/Pictures
Created Sunday. 19 August 2012 13:13
Modified: Thursday. 7 February 2013 11:43
Label: x » * * * „ _ _
Shared folder

e N am e & E xtension:

Hide extension

Figure 12.28 A before and after chunked dialogue




Techniques for designing interactive systems

Time limitations
Memories, particularly those in short-term or working memory, are surprisingly short-lived,
and even in ideal conditions they will persist for only 30 seconds. So, it is essential to make
important information presented persist (Figure 12.29); that is, do not flash an alert such
as ‘Cannot save file’ onto a screen for a second or two and then remove it. Insist that a but­
ton, typically ‘OK’, is pressed. ‘OK1in this instance really means ‘I acknowledge the message’.

Figure 12.29 An example
of a persistent alert box

Recall and recognition

Chapter 21 examines
these issues more closely

Another guideline derived from our knowledge of memory is to design for recognition
rather than recall. Recall is the process whereby individuals actively search their memo­
ries to retrieve a particular piece of information. Recognition involves searching your
memory and then deciding whether the piece of information matches what you have in
your memory store. Recognition is generally easier and quicker than recall.

Challenge 12.3

Find instances of designing for recall and recognition in software you use regularly.
Hint: websites requiring form-filling are often good sources of examples.

Designing for memory
Consider the interface widget in Figure 12.30. This is an image of the formatting palette
which is part of the version of Microsoft Word current at the time of writing. Microsoft
have extensive usability laboratories and the design of this application will have ben­
efited from a sound understanding of the capabilities of people. As such it is an excel­
lent example of designing for memory and embodies a whole series of design principles
reflecting good design practice:
• The palette has been designed to use recognition rather than recall. The drop-down
menus for style, name and size remove the need to recall the names of the fonts
installed and the range of styles available. Instead the main memory mechanism is
recognition. In addition to this, the burden on working memory is kept to a mini­
mum using selection rather than having to memorize the name of a font (e.g. Zapf
Dingbats) and then having to type it correctly in a dialogue box.
• The palette has been organized into four chunks - font, alignment and spacing, bor­
ders and shading, and document - which are logical groups or chunks of functions.
• The use of meaningful associations: B stands for bold, I for italic. It is good design
practice to use these natural mappings.
• The palette also relies on aspects of visual processing and the use of icons.
As we have seen, it is much easier to recognize something than to recall it. Novices
prefer menus because they can scroll through the list of options until a particular

Chapter 12 • Visual interface design

Format Font



Bullets and Numbering...
Borders and Shading...

Drop Cap...

Text Direction...
Change Case...
Form at A u toShape/Picture

Figure 12.30 Interface
widgets in OS X


command is recognized. Experts, however, have been reported as being frustrated in
scrolling through a series of menus (particularly nested menus) and often prefer key­
board shortcuts instead (e.g. < alt>-F-P- instead of select File menu / Print
/ OK). Interactive systems should be designed to accommodate both styles of working.
Further key evidence of the advantage of recognition over recall can be seen in the use
of picklists. Picklists have two clear advantages over simply asking someone to recall a
specific name, or any other piece of data. They offer help when we are faced with trying
to recall something that is on the tip of our tongue or something that is ambiguous (as in
the example of Figure 12.31 which identifies one of several London airports) or which
may be difficult to spell. Consider the next two examples: imagine you
are trying to book a flight from Edinburgh to London. You know that
the target airport is not London Heathrow but one of the others and
Flig h ts |
are confident that you will be able to recognize the specific airport
Book a cheap flight
without difficulty from the list more easily than from unaided memory.
Edinburgh (EDO
Figure 12.31 is an image of a standard Web pull-down picklist.
London Stansted is easier to recognize than trying to remember
London (All Airports)
Flying out on
(a) how to spell it - Stanstead, Standsted or Stansted7 - and (b) the
official airline abbreviation (STN). The use of a picklist can also sig­
25 {
September 2(
nificantly improve the spelling of the documents we produce. Current
Returning on
versions of Microsoft Word identify misspelled words by underlining
nc t
just one way * 3
them with a red wavy line. Left-clicking on the word drops down a
□ Flexible on dates?
picklist of alternative spellings. This approach has also been adopted
by modern visual (software) development environments where not
1 5 adults
only misspelled commands are identified but the syntax of commands
0 i children (under 16 years)
is checked. Figure 12.32 is an illustration of this.
0 i infants (under 2 years)
The recent use of thum bnails is another example of how recog­
nition is more effective than recall. Figure 12.33 is a screenshot of
the My Pictures of a computer running the Windows 7 operating sys­
_________________________ /
tem. The folder contains a number of thumbnails, that is, very small
(thumbnail-sized) images of the contents of the files in the folder.
Each is immediately recognizable and reminds the person of the origi- Figure 12.31 Flying to London
nal content.



Part II

Techniques for designing interactive systems

As the blind man behind his leader w alks,
Lest he should e rr, or stum ble unaw ares
On w hat might harm him , or perhaps destroy,
I ioum ev'd through that bitter air and foul,
Still list'nino to mv escort's warning voice.
ot." Straight I heard
"Look th at fr listening
pray for peace,
V oices, and i Ignore
ib of God
And for comi Ignore All
That takgth
•elude still
all the choir,
W as "Agnus
at perfect seem 'd
One voice, o AutoCorrect
i th ese I hear
The concord
Spirits, O m aster?" I exclaim 'd ; and he:
"Thou aim 'st aright: th ese loose the bonds of w ra th .”

Figure 12.32 Spelling

Colour blindness
The term colour blind is used to describe people with defective colour vision. Redgreen colour blindness (i.e. the inability to distinguish reliably between red and green)
is the most common form, affecting approximately 1 in 12 men (8 per cent) and 1 in 25
women (4 per cent). It is a genetic disorder with a sex-linked recessive gene to blame hence the greater number of men being affected. A second and rarer form of colour
blindness affects the perception of the colours blue-yellow. The rarest form of all results
in monochromatic vision in which the sufferer is unable to detect any colour at all.
______________________________________________________________________________________ ^

Chapter 12 • Visual interface design

Designing with colour
Colour is very important to us. To describe someone as being colourless is to say that
they are without character or interest. Designing colour into interactive systems is
very difficult. If it were otherwise, why are most domestic electronic devices black?
The design language adopted by Microsoft (discussed in Chapter 9) makes use of col­
ourful tiles for its design and Apple have long favoured smooth blue and graphite grey
as their livery.
Aaron Marcus’s excellent book Graphic Design for Electronic Documents and User
Interfaces (Marcus, 1992) provides the following rules.
Rule 1 Use a maximum of 5 ± 2 colours.
Rule 2
Rule 3

Use foveal (central) and peripheral colours appropriately.
Use a colour area that exhibits a minimum shift in colour and/or size if the
colour area changes in size.

Rule 4

Do not use simultaneous high-chroma, spectral colours.

Rule 5

Use familiar, consistent colour codings with appropriate references.

Table 12.1 holds a number of Western (Western Europe, the United States and Australia)
denotations as identified by Marcus. These guidelines are, of course, just that - guide­
lines. They may not suit every situation but should at the very least provide a sound
starting point. One final caveat - colour connotations can vary dramatically even within
a culture. Marcus notes that the colour blue in the United States is interpreted differ­
ently by different groups - for healthcare professionals it is taken to indicate death; for
movie-goers it is associated with pornography; for accountants it means reliability or
corporateness (think of ‘Big Blue’ - IBM).
Table 12.1

So m e W estern colour co nventio ns


Danger, hot, fire


Caution, slow, test


Go, okay, clear, vegetation, safety


Cold, water, calm, sky

Warm colours
Cool colours

Action, response required, proximity
Status, background information, distance

Greys, white and blue


Source: After Marcus, Aaron, Graphic Designfor Electronic Documents and User Interfaces, 1st, © 1991. Printed and
Electronically reproduced by permission of Pearson Education, Inc., Upper Saddle River, Newjersey.

Error avoidance design guidelines
The following design guidelines have been drawn (and edited) from Reason and
Norman’s design principles for minimizing error (cf. Reason, 1990, p. 236):
• Use knowledge both in the world and in the head in order to promote a good concep­
tual model of the system; this requires consistency of mapping between the design­
er’s model, the system model and the user’s model.
• Simplify the structure of tasks so as to minimize the load upon vulnerable cognitive
processes such as working memory, planning or problem solving.
• Make both the execution and the evaluation sides of an action visible. Visibility in
regard to the former allows users to know what is possible and how things should

-> Human error is covered
in Chapter 21



Part II • Techniques for designing interactive systems




be done; visibility on the evaluation side enables people to gauge the effects of
their actions.
Exploit natural mappings between intentions and possible actions, between actions
and their effects on the system, between the actual system state and what is perceiv­
able, and between the system state and the needs, intentions and expectations of
the user.
Exploit the power of constraints, both natural and artificial. Constraints guide people
to the next appropriate action or decision.
Design for errors. Assume that they will happen, then plan for error recovery. Try to
make it easy to reverse operations and hard to carry out non-reversible ones. Exploit
forcing functions such as wizards that constrain people to use a limited range of
When all else fails, standardize actions, outcomes, layouts, displays, etc. The dis­
advantages of less than perfect standardization are often compensated for by the
increased ease of use. But standardization for its own sake is only a last resort. The
earlier principles should always be applied first.

Error message design guidelines
• Take care with the wording and presentation of alerts and error messages.
• Avoid using threatening or alarming language in messages (e.g. fatal error, run
aborted, kill job, catastrophic error).
• Do not use double negatives as they can be ambiguous.
• Use specific, constructive words in error messages (e.g. avoid general messages such
as ‘invalid entry’ and use specifics such as ‘please enter your name’).
• Make the system ‘take the blame’ for errors (e.g. ‘illegal command’ versus ‘unrecog­
nized command’).
• DO NOT USE ALL UPPERCASE LETTERS as it looks as if you are shouting - instead,
use a mixture of uppercase and lowercase.
• Use attention-grabbing techniques cautiously (e.g. avoid over-using ‘blinks’ on Web
pages, flashing messages, ‘you have mail’, bold colours, etc.).
• Do not use more than four different font sizes per screen.
• Do not over-use audio or video.
• Use colours appropriately and make use of expectations (e.g. red = danger, green = ok).

Principles from navigation
Navigation is discussed in Chapter 25, highlighting the importance of people having
both survey knowledge and route knowledge in understanding and wayfinding through
an environment. Apple user experience guidelines agree:
Give People a Logical Path to Follow. People appreciate knowing where they are in an
app and getting confirmation that they're on the right path. Make the path through the
information you present logical and easy for users to predict. In addition, be sure to provide
markers - such as back buttons - that users can use to find out where they are and how
to retrace their steps. In most cases, give users only one path to a screen. If a screen needs
to be accessible in different circumstances, consider using a modal view that can appear
in different contexts.
Source: See source of Further thoughts

Chapter 12 • Visual interface design

Apple’s user experience guidelines for iOS apps
Focus on the Primary Task
Elevate the Content that People
Care About

Handle Orientation Changes
Make Targets Fingertip-Size

Think Top Down

Use Subtle Animation to

Give People a Logical Path to Follow

Support Gestures Appropriately

Make Usage Easy and Obvious
Use User-Centric Terminology

Ask People to Save Only When

Minimize the Effort Required for User

Make Modal Tasks Occasional
and Simple

Downplay File-Handling Operations

Start Instantly

Enable Collaboration and

Always Be Prepared to Stop

De-emphasize Settings
Brand Appropriately

If Necessary, Display a License
Agreement or Disclaimer

Make Search Quick and Rewarding

For iPad:

Entice and Inform with a Well-Written

Enhance Interactivity (Don't Just
Add Features)

Be Succinct

Reduce Full-Screen Transitions

Use Ul Elements Consistently

Restrain Your Information

Consider Adding Physicality and
Delight People with Stunning



Don't Quit Programmatically

Consider Using Popovers for Some
Modal Tasks
Migrate Toolbar Content to the Top


12.5 Information design


In addition to designing screens and individual widgets for people to interact with a sys­
tem or device, interaction designers need to consider how to lay out the large amounts
of data and information that are often involved in applications. Once designers have
worked out how best to structure and organize the information, they need to provide
people with methods to interact with it. The tools and techniques for navigating through
large amounts of information have a big impact on the inferences people will be able to
make from the data and the overall experience that people will have.
Jacobson (2000) argues that the key feature of information design is that it is design
dealing with meanings rather than materials. Information design is essentially to do
with sense-making, with how to present data (often in large amounts) in a form that
people can easily understand and use. Information designers have to understand the
characteristics of the different media being used to present data and how the medium
affects how people move through structures.

See also the discussion
of information spaces in
Chapter 18

2 79

Part II • Techniques for designing interactive systems

Information design is traditionally traced back to the work of Sir Edward Playfair
in the eighteenth century and to the work of the French semiologist Jacques Bertin
(1981). Bertin’s theories of how to present information and on the different types of
visualizations have been critical to all work since. The work of Edward Tufte (1983,
1990, 1997) shows just how effective good information design can be (see Box 12.5).
He gives numerous examples of how, in finding the best representation for a prob­
lem, the problem is solved. Clarity in expression leads to clarity of understanding. He
describes various ways of depicting quantitative information such as labelling, encod­
ing with colours or using known objects to help get an idea of size. He discusses how
to represent multivariant data in the two-dimensional space of a page or a computer
screen and how best to present information so that comparisons can be made. His
three books are beautifully illustrated with figures and pictures through the centuries
and provide a thoughtful, artistic and pragmatic introduction to many of the issues of
information design.

Edward Tufte
In the introduction to Visual Explanations, Tufte (1997, p. 10) writes
My three books on information design stand in the following relation:
The Visual Display of Quantitative Information (1983) is about pictures of numbers,
how to depict data and enforce statistical honesty.
Envisioning Information (1990) is about pictures of nouns (maps and aerial photo­
graphs, for example, consist of a great many nouns lying on the ground). Envisioning
also deals with visual strategies for design: color, layering and interaction effects.
Visual Explanations (1997) is about pictures of verbs, the representation of mecha­
nism and motion, or process and dynamics, or causes and effects, of explanation
and narrative. Since such displays are often used to reach conclusions and make
decisions, there is a special concern with the integrity of the content and the design.

Figure 12.34 is one of Tufte’s designs and shows a patient’s medical history involving
two medical and two psychiatric problems.
Harry Beck’s map of the London Underground is often cited as an excellent piece of
information design. It is praised for its clear use of colour and its schematic structure not worrying about the actual location of the stations, but instead concerned with
their linear relationships. The original map was produced in 1933 and the style and
concepts have remained until now. However, it is interesting to note how nowadays with the proliferation of new lines - the original structure and scheme is breaking
down. With only a few Underground lines, the strong visual message could be con­
veyed with strong colours. With a larger number of lines the colours are no longer
easily discernible from one another. Figure 12.35 shows the map from 1933 and a
recent version.
Another key player in the development of information architecture and informa­
tion design is Richard Saul Wurman. His book Information Architects (Wurman, 1997)
provides a feast of fascinating images and reflections on the design process by lead­
ing information designers. Wurman’s own contribution dates from 1962 and includes a
wide variety of information design cases, from maps comparing populations, to books
explaining medical processes, to his New Road Atlas: US Atlas (Wurman, 1991), based
on a geographical layout with each segment taking one hour to drive. Figure 12.36
shows an example from his Understanding USA book (Wurman, 2000).

Chapter 12 • Visual interface design

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1050 ml


5.1 mmol/l


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Figure 12.34 Examples of Tufte's work
(Source: After Tufte (1997), p. 110 and p. 111. Courtesy of Edward R. Tufte and Seth M. Powsner)

A number of authors are keen to ground information design in theory - particularly
theories of perception and cognition. Indeed, some of these theoretical positions, such
as Gestalt principles described above, are useful. General design principles of avoid­
ing clutter, avoiding excessive animations and avoiding clashing colours also help make
displays understandable. Bertin’s theories and modern versions such as that of Card
(2012) are useful grounding for anyone working in the area. Card (2012) provides a
detailed taxonomy of the various types of visualization and provides details on different
types of data that designers can deal with. He also discusses the different visual forms
that can be used to represent data.



Part II • Techniques for designing interactive systems

Figure 12.35 Maps of the London Underground rail network: left, in 1933; right, now
(Source: Screenshot (top left) from London underground map by H.C. Beck (1993), © TfL from the London Transport Museum collection; Screenshot
(top right) from London underground map, 2009. © TfL from the London Transport Museum collection)

Figure 12.36 Illustration from
Richard Saul Wurman's book
Understanding USA
(Source: Wurman, 2000, designed by
Joel Katz)

<- Design languages are
discussed in Chapter 9

Essentially, though, information design remains a design discipline rather than an
engineering one. There are many methods to help designers understand the problems
of information design in a particular context (and taking a human-centred view is the
most important), but there can be no substitute for spending time critiquing great
designs and looking at the reflection of designers on their creative and thinking pro­
cesses. Readers are encouraged to follow up the references at the end of this chapter.
When developing a scheme of information design in a given context, designers
should realize that they are developing visual ‘languages’. The visual language of infor­
mation design is an important part of these. Designers will imbue colours, shapes and
layouts with meanings that people have to come to understand.

12.6 Visualization
The other key feature of information design that the modern information architect or
designer might get involved with is interactive visualization. With the vast amounts of
data that are available, novel ways of presenting and interacting with this are neces­
sary. Card et al. (1999) is an excellent set of readings covering many of the pioneer­
ing systems. Spence (2001) provides a good introduction to the area and Card (2012)

Chapter 12 • Visual interface design

provides a thorough and accessible treatment of the options. Interactive visualizations
are concerned with harnessing the power of novel interactive techniques with novel
presentations of large quantities of data. Indeed, Card (2012) argues that visualization
is concerned with ‘amplifying cognition’. It achieves this through:

increasing the memory and processing resources available to people,
reducing the search for information,
helping people to detect patterns in the data,
helping people to draw inferences from the data,
encoding data in an interactive medium.

Ben Shneiderman has long been a designer of great visualizations (see
nben/index.html). He has a ‘mantra’, an overriding principle for developing visualizations:
Overview first, zoom and filter, then details on demand.
The aim of the designer is to provide people with a good overview of the extent of the whole
dataset, to allow zooming in to focus on details when required, and to provide dynamic
queries that filter out the data that is not required. Card (2012) includes retrieval by exam­
ple as another key feature. So rather than having to specify what is required in abstract
terms, people request items similar to one they are viewing. Ahlberg and Shneiderman’s
(1994) Film Finder is an excellent example of this (Figure 12.37). In the first display we
see hundreds of films represented as coloured dots and organized spatially in terms of
year of release (horizontal axis) and rating (vertical axis). By adjusting the sliders on the

(Source: Ahlberg, C. and Shneiderman, B. (1994) Visual information seeking: Tight Coupling of Dynamic Query Filters with Starfield Displays,
Proceedingsof theCHI'94 Conference, pp. 313-317. © 1994 ACM, Inc. Reprinted by permission.)



Part II • Techniques for designing interactive systems

right-hand side, the display zooms in on a selected part of the first display, allowing names
to be revealed. Effectively the sliders provide dynamic queries on the data, allowing people
to focus in on the part that is of interest. Clicking on a film brings up the details of a film,
allowing this to be used for retrieval-by-example style further searches.
Another classic example of a visualization is ConeTree (Figure 12.38) Various facili­
ties are available that allow people to ‘0 / around the display, identifying and picking
out items of interest. Once again the interactive visualization allows for overview first,
zoom and filter, and details on demand. The key thing with visualizations is to facilitate
‘drilling down’ into the data.
Figure 12.39 shows the display of the stock market at This dis­
play is known as a ‘tree map’. The map is colour-coded from red through black to green,
indicating a fall in value, through no change to a rise in value. The brightness of colour
indicates the amount of change. Companies are represented by blocks, the size of the
block representing the size of the company. Mousing over the block brings up the name
and clicking on it reveals the details.
Figure 12.40 shows a different type of display where connections are shown by
connecting lines. It is an on-line thesaurus that demonstrates the ‘fish-eye’ capability
which again allows for the focus and context feature required by visualizations. This
allows users to see what is nearby and related to the thing that they are focusing on.
There are many more exciting and stimulating visualizations built for specific applica­
tions. Card (2012) lists many and Card etal. (1999) discuss specific designs and their

Figure 12.38 ConeTree

Chapter 12 • Visual interface design

Figure 12.39
(Source: © SmartMoney 2004. All rights reserved. Used with permission.
SmartMoney is ajoint venture of Dowjones & Company, Inc. and Hearst Communications, Inc.)

Figure 12.40 The Visual
thesaurus Visual Thesaurus™
(powered by Thinkmap®) © 2004
Plumb Design, Inc. All rights reserved)

Card (2012) argues that the key decision in any visualization is to decide which
attributes of an object are to be used to spatially organize the data. In Film Finder it is
rating and year. In it is the market sector. Once this has been decided,
there are relatively few visual distinctions that can be made. The designer can use
points, lines, areas or volumes to mark different types of data. Objects can be connected
with lines or enclosed inside containers. Objects can be distinguished in terms of colour,
shape, texture, position, size and orientation. Other visual features that can be used to
distinguish items include resolution, transparency, arrangements, the hue and satura­
tion of colours, lighting and motion.
There are a number of novel visualization applications that are available to view cer­
tain websites and other large datasets such as collections of photos. Cool Iris is one such
application, facilitating panning, zooming, and moving through the data in an extremely
engaging way. DeepZoom is a zoomable interface based on Silverlight from Microsoft
and Adobe market Papervision which provides similar functionality based on Flex.

2 85


Part II • Techniques for designing interactive systems

Summary and key points
The design of visual interfaces is a central skill for interactive system designers. There
are principles of aesthetics to consider (we covered aesthetics in Chapter 5), but mostly
designers need to concentrate on understanding the range of 'widgets' that they have
available and how they can be best deployed. It is how the overall interaction works as a
whole that is important.
• Graphical user interfaces use a combination of WIMP features and other graphical
objects as the basis of their design.
• Design guidelines are available from work in psychology and perception and from
principles of graphic design.
• In information design interactive visualizations need to be considered when there is a
large amount of data to be displayed.

E x e rc is e s
Examine the tabbed dialogue widget shown in Figure 12.30. Which of the
major components of human cognition are being addressed in the design?
2 (Advanced) I pay my household credit card bill every month using my debit
card (which is used for transferring money from my bank account). The
procedure is as follows:
• I have to phone the credit card company on a 12-digit telephone number.
• Then from the spoken menu I press 2 to indicate I wish to pay my bill.
• I am instructed to enter my 16-digit credit card number followed by the
hash key.
• I am then told to enter the amount I want to pay in pounds and pence
(let's imagine I wish to pay £500.00 —7 characters).
• Then I am told to enter my debit card number (16 digits) followed by the
hash key.
• Then I am asked for the debit card's issue number (2 digits).
• Then the system asks me to confirm that I wish to pay £500.00, by pressing
the hash key.
• This ends the transaction. The number of keystrokes totals 12 + 1+16 + 7 +
16 + 2 + 1 =55 keystrokes on a handset which does not have a backspace key.
What design changes would you recommend to reduce the likelihood of
making a mistake in this complex transaction?

Further reading
Card, S. (2012) Information visualizations. In Jacko, J.A. (eds.) The Human-Computer
Interaction Handbook, 3rd edn. CRC Press, Taylor and Francio, Boca Raton, FL, 515-48.
Marcus, A. (1992) Graphic Design for Electronic Documents and User Interfaces. ACM Press,
New York.

Chapter 12 • Visual interface design

Getting ahead
Cooper, A., Reiman, R. and Cronin, D. (2007) About Face 3: The Essentials of Interaction
Design. Wiley, Hoboken, NJ. Provides a wealth of detailed interface design guidance and numer­
ous examples of good design.

Web links
For further information on Horton's approach to icon design see
The accompanying website has links to relevant websites. Go to

Comments on challenges
Challenge 12.1
Saying 'Computer1puts the computer into the correct mode to receive commands. In the lift the
only commands the system responds to are instructions on which deck to go to. Thus the context
of the interaction in the lift removes the need fora command to establish the correct mode.

Challenge 12.2
Radio buttons for the colour scheme - only one option can be chosen. The incoming mail prefer­
ences use checkboxes since multiple preferences can be selected.

Challenge 12.3
Again, instances abound. An example of design for recognition is the provision of a drop-down list
of all airports for a particular city destination in a flight booking site rather than expecting custom­
ers to recall which airports exist and type in the exact name.


Chapter 13
M ultim odal interface design



13.1 Introduction 289
13.2 Interacting in mixed
13.3 Using sound at the
interface 294

In the design of interactive systems one thing that is certain is that
designers will increasingly be making use of technologies that go
far beyond the screen-based systems that used to be their main
concern. Designers will develop multimedia experiences using a
variety of modalities (sound, vision, touch, etc.) combined in novel

13.4 Tangible interaction 298

ways. They will be mixing the physical and the digital. In this chapter

13.5 Gestural interaction and

Further reading 305

we look at issues of designing for multimodal and mixed reality
systems, at designing for sound, touch and at wearable computing.
(Related material on design can be found in Chapter 18 on ubiquitous
computing and Chapter 19 on mobile computing. Auditory and haptic
perception is discussed in Chapter 25.)

Web links 306

After studying this chapter you should understand:

reality 291

surface com puting 302
Sum m ary and key points 305
Exercises 305

Comments on challenges 306

• The spectrum of media, modalities and realities
• The key design guidelines for designing for audition
• The role of touch, haptics and kinaesthetics
• Designing for tangible and wearable computing.

Chapter 13 • Multimodal interface design

13.1 Introduction
Sutcliffe (2012) distinguishes several key concepts of communication:
• Message is the content of a communication between a sender and a receiver.
• Medium is the means by which a message is delivered, and how the message is
• Modality is the sense by which a message is sent or received by people or machines.

—> Som e related ideas of
sem iotics are discussed in
C h ap ter 24

A message is conveyed by a medium and received through a modality.
The term ‘mixed reality’ was coined by Milgram et al. in 1994 to encompass a number
of simulation technologies, including augmented reality (digital information added to
the real world) and augmented virtuality (real information added to the digital world).
The result was the Reality-Virtuality continuum, as shown in Figure 13.1. The contin­
uum can be described as ‘the landscape between the real and the virtual’ (Hughes et al.
2004), where the two are blended together. Milgram et al. (1994) did not see this as
an adequate representation of mixed reality and instead proposed a three-dimensional
taxonomy. In essence there are three scales covering:
• ‘Extent of World Knowledge’ (the degree to which the world is modelled in the
• ‘Reproduction Fidelity’ (the quality of resolution and hence the realism of the real
and virtual worlds)
• ‘Extent of Presence Metaphor’ (the degree to which people are meant to feel present
in the system).
However, it is the one-dimensional continuum that has been most widely accepted
(Hughes et al, 2004; Nilsen, etal. 2004).
The Augmented Reality (AR) region of the scale aims to bring digital information into
the real world whereas augmented virtuality applications would include Google Earth.
By far the most common blending in AR is that of visual stimuli. Here a live video stream
can be enhanced with computer-generated objects (rendered so that they appear to be
within the actual scene). Methods of presenting this visual information fall into the two
main categories: immersive (where people see no view other than that of the mixed
reality environment) and non-immersive (where the mixed reality environment takes
up only a portion of the field of view). The latter method can make use of a vast range
of displays, including computer monitors, mobile devices and large screen displays. For
immersive presentations people will generally wear a special helmet which incorporates
a display, and which excludes any other view of the outside world. These head-mounted
displays (HMDs) are split into two categories: video see-through (where the real world is
recorded by a video camera and people are presented with a digital display) and optical
see-through (where the display screens are semi-transparent, allowing a direct view of
the real world and only adding computer graphics on top).

M ix e d r e a lit y ( M R )


Fig u re 13.1

reality (A R )

Reality-Virtuality (RV) Continuum

(Source: Adapted from Milgram, P.

e t a l.


virtuality (AV) environment

Presence is discussed
in Chapter 24



Part II • Techniques for designing interactive systems

The second most common (and often used in conjunction with the previous) is audi­
tory simulation. In this case computer-generated sounds can be supplied in such a way
that they appear to originate from locations within the real environment. Common
methods include the use of headphones or speaker arrangements, but there are more
exotic technologies such as a hypersonic sound device that can target a specific location
and make it appear that the sound is originating from there.
Of the remaining three senses, the sense of touch (or haptics) is the most developed
field, with work ranging from the physical sensation of holding objects to simulating the
sensation of touching different surfaces (Hayward et a l, 2004).
Smell has been simulated, but with limited success. Developments are even being
made at the University of Tsukuba in simulating the sensation of eating (Iwata et al.,
2004). However, these systems are currently unwieldy and limited in application.

Smell, taste and emotion
Smell and taste are challenging senses for digital technologies because scientists have not
been able to identify the basic components o f these senses. Whereas a particular colour can
be made up from a combination of three primary colours red, green and blue, w e have no
ideas what the primary components are for smell and taste. Moreover, since these are inher­
ently analogue media, w e can't digitize them to transmit the information over networks.
People have developed smell projectors that can deliver a burst o f a particular per­
fum e smell but it is difficult to keep the smell localized and to get rid o f the smell when
that part of the interaction is over. It is sometim es said that taste can be described in
term s o f five basic tastes; sweet, sour, salty, bitter and um am i. However, there are m any
other sensations that can be detected by the tongue that contribute to the overall sen­
sation of a particular taste.
Smell is particularly connected w ith em otions and w ill often evoke m em ories o f past
events and people. Scientists believe this is because the olfactory system is connected
into the lim bic system in the body.
Adrian Cheok at the Mixed Reality Lab in Keio University in Japan has been experi­
m enting w ith a num ber of different ways o f generating and interacting w ith taste and
sm ell. The food project there is looking at producing digitized foods using a 3D printer
and synthetic food material (Figure 13.2).
W e can already send hugs and kisses to o ur loved ones o ver the Internet using
devices such as the hug-me T-shirt. H ow long is it before w e can send digitized birthday
cakes or the smell of baking bread?

Figure 13.2 A food
(Source: Mixed Reality
Lab, National University of

Chapter 13 • Multimodal interface design

13.2 Interacting in mixed reality
Interaction tools used in virtual reality include: ‘spacemice’, which expand the
two degrees of freedom in traditional mice (horizontal and vertical movement)
to six degrees of freedom (horizontal, vertical, depth movements and yaw, pitch
and roll rotations); ‘data gloves’, where a glove is fitted with sensors to track hand
location and finger positions and allows the grabbing and manipulation of virtual
objects; and ‘wands’, such as the Wii, which are sticks again with six degrees of
freedom and various input controls such as buttons and scrollers. These tools offer
full three-dimensional input. TACTool has added tactile feedback to a wand device
(Schoenfelder et a l, 2004), and interaction slippers, which add some functionality
of datagloves to feet. Microsoft’s Kinect allows for hand, arm and body gestures to
interact with the content.
Mixed reality interaction demands the most from interaction designers as they grap­
ple with technological problems and usability issues side by side. One technical issue
is that of accurately aligning the real and virtual environments: a process called ‘regis­
tration’ (Azuma, 1997). A number of systems allow the technology used for perform­
ing this registration to also offer the kind of 3D input provided by the tools discussed
previously. A notable example of this is the ARToolkit (2007), a software library that
includes facilities required to optically track images placed in the real world, and align
computer-generated graphics based on their position and orientation.
Quick Response (QR) codes can be used to connect the real and virtual worlds as can
data from the Global Positioning System (GPS). Images can be used as a marker, so that
when a smartphone captures the image it triggers the delivery of some content such as
a video. It all depends on the accuracy required. A GPS trigger, for example, could be
accurate to 5 metres (and accuracy varies with the actual device used), but this would
be no use for a very precise application such as remote surgery when the alignment of
real and virtual worlds is a major technological undertaking.
A huge number of applications in the field of AR use the ARToolkit; for example, in
the Tangible Hypermedia application (Sinclair etal., 2002), some markers are used for
objects (planes in the examples), and others as data sources called ‘spice piles’. By mov­
ing a spice pile near to an object and shaking it, data is sprinkled onto the object in the
form of labels. The longer a person shakes the spice pile, the more detailed the informa­
tion becomes. People can also shake the object, dislodging some of the spice dust, and
reducing the complexity of the labels.
When mixed reality is applied to games the range of input methods becomes more
diverse. Some applications use traditional game-controller-style inputs, using aug­
mented reality as a replacement for a computer monitor. Examples include ARWorms
(Nilsen et al, 2004) and Touchspace (Cheok et a l, 2002).
However, Touchspace also uses full body interaction as a method of input. People nav­
igate around a real-world space (an empty room) with a window onto a virtual world.
The first objective in the game is to find a witch’s castle, and then to battle her in AR.
A number of applications go further with full body interaction, not limiting themselves
to a single room. One of the most advanced is the Human Pacman game (Cheok et al,
2003) where participants take one of three roles: a Pacman (collecting spheres from the
environment by walking over them ); a ghost (aiming to capture the Pacmen by touch­
ing their shoulders - where there is a touch sensor); or helper (given an overview of
the game through a traditional interface, and given the task of guiding either a ghost
or a Pacman). As well as collecting virtual objects (virtual spheres), players also collect
ingredients to make ‘cookies’ (similar to power pills in the original Pacman) by picking
up Bluetooth-enabled physical objects. The AR Quake system (Thomas et al., 2000) is



Part II

Techniques for designing interactive systems

Figure 13.3 AR Quake
(Source: Bruce H. Thomas)

similar to the Human Pacman work in that an outdoor AR game was developed. Players
in a real world do battle with virtual monsters (Figure 13.3).
Immersive virtual reality requires people to wear a light-excluding helmet (an HMD head-mounted display) which houses the display, and a data glove which facilitates the
manipulation of virtual objects within virtual reality. An HMD consists of two colour
displays located in line with one’s eyes and a pair of stereo earphones. An HMD also has
a head tracker which provides information about the wearer’s position and orientation
in space. Figure 13.4 offers a view of the interior of an HMD, while Figure 13.5 shows
one in use. Gloves equipped with sensors (data gloves) are able to sense the movements
of the hand, which are translated into corresponding movements in the virtual environ­
ment. Data gloves are used to ‘grasp’ objects in virtual environments or to ‘0 / through

Figure 13.4

An interior view of an HMD

(Source: Phil Turner)

Figure 13.5


(Source: Phil Turner)

Chapter 13 • Multimodal interface design

virtual scenes. Figure 13.6 is an illustration of a force-feedback data glove which uses
actuators to ‘feed back’ an impression of, say, the grasped object.
The main features of immersive VR are:
• Head-referenced viewing provides a natural interface for navigation in three­
dimensional space and allows for look-around, walk-around and fly-through capa­
bilities in virtual environments.
• Stereoscopic viewing enhances the perception of depth and the sense of space.
• The virtual world is presented in full scale and relates properly to human size.
• Realistic interactions with virtual objects via data glove and similar devices allow for
manipulation, operation and control of virtual worlds.
• The convincing illusion of being fully immersed in an artificial world can be enhanced
by auditory, haptic and other non-visual technologies.
The original Computer Augmented Virtual Environment (CAVE) was developed at the
University of Illinois at Chicago and provides the illusion of immersion by projecting ste­
reo images on the walls and floor of a room-sized (a pretty small room, it should be said)
cube. People wearing lightweight stereo glasses can enter and walk freely inside the
CAVE. A panorama is like a small cinema. The virtual image is projected onto a curved
screen before the ‘audience’ who are required to wear liquid-crystal display (LCD) shut­
tered spectacles (goggles). The shutters on the LCD spectacles open and close over
one eye and then the other 50 times a second or so. The positions of the spectacles are
tracked using infra-red sensors. The experience of a panorama is extraordinary, with
the virtual world appearing to stream past the audience. Panoramas are expensive and
far from portable.

Figure 13.6 A forcefeedback data glove
(Source: Image courtesy www.5DT.

Non-immersive virtual reality (sometimes called desktop virtual reality) can be
found in a wide range of desktop applications and games as it does not always require
specialist input or output devices.
Multimodal systems that do not mix realities, but combine gesture, speech, move­
ment and sound, are increasingly common and raise their own issues to do with syn­
chronizing the modalities. One of the earliest systems was ‘Put That There’ (Bolt, 1980),
which combined speech and gesture. More recent examples include the ‘Funky Wall’
interactive mood board described in Chapter 9, which also includes proximity to the
wall as a modality (Lucero e ta l, 2008).



Part II • Techniques for designing interactive systems

13.3 Using sound at the interface
Sound is an increasingly important part of interface design in both mixed reality and
multimodal systems. The following section is based closely on Hoggan and Brewster’s
chapter on ‘Non-speech auditory and crossmodal output’ (Hoggan and Brewster, 2012)
in The Human-Computer Interaction Handbook. The main headings are theirs.

Vision and hearing are interdependent
While comic book superheroes may acquire super-sensitive hearing on the loss of their
sight, for the rest of us ordinary mortals our visual and auditory systems have evolved to
work together. It is interesting to contrast the kinds and range of information our eyes
and ears provide. Sight is a narrow, forward-facing, richly detailed picture of the world,
while hearing provides information from all around us. An unexpected flash of light or a
sudden movement orients our heads - and hence our hearing - to the source; the sound
of a car approaching from behind makes us turn to look. Both sound and vision allow us
to orient ourselves in the world.

Reduce the load on the visual system
This design guideline and the next two are very closely related. It is now recognized
that modern, large or even multiple-screen graphical interfaces use the human visual
system very intensively - perhaps over-intensively (see Figure 13.7). To reduce this sen­
sory overload, key information could be displayed using sound, again to redistribute the
processing burden to other senses.

Figure 13.7 A typical visually cluttered desktop

Chapter 13 • Multimodal Interface design

Challenge 13.1
S u g g e s t th re e d iffe r e n t w a y s in w h ic h in fo rm a tio n b e lo n g in g to a ty p ic a l d e s k to p c o u ld b e
d is p la y e d u sin g so u n d .




- ...................................................................................h









Reduce the amount of information needed on screen
One of the great design tensions in the creation of mobile and ubiquitous devices is
to display a usable amount of information on a small screen - small as in palm-sized,
or pocket-sized, or carried or worn without a course in body building. The problem is
that we live in an information-rich society. When moving information from one place
to another was expensive, the telegram ruled: ‘Send money. Urgent’. Now we are likely
to send a three-part multimedia presentation complete with streamed video, with the
theme of ‘send money, urgent’. Mobile and ubiquitous devices have very small screens
which are unsuited to viewing large bodies of data. To minimize this problem, informa­
tion could be presented in sound in order to free screen space.

Reduce demands on visual attention
Again in the context of mobile and ubiquitous devices, there is an uneasy and at present
unsatisfactory need to switch from attending to the world - crossing the road, driving
a car, following a stimulating presentation - to paying attention to the display of such
devices. As we saw earlier, the UK government made it an offence from December 2003
to drive a car while using a mobile phone (hands-free phones excepted). The need for
visual attention in particular could be reduced if sound were used instead.

The auditory sense is under-utilized
We listen to highly complex musical structures such as symphonies and operas. These
pieces of music comprise large complex structures and sub-structures. This suggests that
there is, at least, the potential of using music to transmit complex information successfully.

Sound is attention-grabbing
While we can look away from an unpleasant sight, the same is not true of an unpleasant
sound. The best we can do is to cover our ears. This makes sound very useful for attract­
ing attention or communicating important information.

To make computers more usable by visually disabled users
While screen readers can be used to ‘read’ on-screen textual information, they cannot
easily read graphical information. Providing some of this information in an auditory
form can help alleviate this problem.

Challenge 13.2
C a n y o u th in k o f p o s s ib le d is a d v a n ta g e s to a u g m e n tin g th e in te r fa c e w ith s o u n d ? O r
c irc u m s ta n c e s w h e re it w o u ld b e in a p p ro p r ia te ?

-» Attention is discussed
in Chapter 21



Part II • Techniques for designing interactive systems

To date, most research on auditory user interfaces (AUIs) has concentrated on the use of
either earcons or auditory icons. Earcons are musical sounds designed to reflect events
in the interface. For example, a simple series of notes may be used to indicate the receipt
of an SMS message on a mobile phone. A different sound is used when an SMS is sent.
In contrast, auditory icons reflect the argument that we make use of many sounds in
the everyday world without thinking about their musical content. The sounds used in
these interfaces are caricatures of everyday sounds, where aspects of the sound’s source
correspond to events in the interface. The sound for an SMS being sent on my phone is
a ‘whoosh’: off it goes.

Earcons are abstract, musical tones that can be used in structured combinations to cre­
ate auditory messages. They were first proposed by Blattner et al. (1989) who defined
earcons as ‘non-verbal audio messages that are used in the computer-user interface to
provide information to the user about some computer object, operation or interaction’.
Earcons are based on musical sounds.
Numerous studies of the usefulness of earcons in providing cues in navigating menu
structures have been conducted. The following study, from Brewster (1998), involved
the creation of a menu hierarchy of 27 nodes and four levels with an earcon for each
node. Participants in the study were asked to determine their location in the hierarchy
by listening to an earcon. Results of this and similar experiments showed that partici­
pants could identify their location with greater than 80 per cent accuracy. This suggests
that earcons are a useful way of providing navigational information. Given their useful­
ness, one proposed use for earcons is in telephone-based interfaces where navigation
has been found to be a problem.
These design guidelines have been adapted from the work of Brewster, Wright and
Edwards (1993). They are quoted more or less verbatim.
• Timbre. Use synthesized musical instrument timbres. Where possible use timbres
with multiple harmonics. This helps perception and avoids masking.
• Pitch. Do not use pitch on its own unless there are very big differences between those
used. Some suggested ranges for pitch are maximum 5 kHz (four octaves above mid­
dle C) and minimum 125-130 Hz (an octave below middle C).
• Register. If this alone is to be used to differentiate earcons which are otherwise the
same, then large differences should be used. Three or more octaves difference give
good rates of recognition.
• Rhythm. Make rhythms as different as possible. Putting different numbers of notes in
each rhythm was very effective. Very short notes might not be noticed, so do not use
less than eighth notes or quavers.
• Intensity. Some suggested ranges are maximum 20 dB above threshold and minimum
10 dB above threshold. Care must be taken in the use of intensity. The overall sound level
will be under the control of the user of the system. Earcons should all be kept within a
close range so that if the user changes the volume of the system no sound will be lost.
• Combinations. When playing earcons one after another, leave a gap between them so that
users can tell where one finishes and the other starts. A delay of 0.1 second is adequate.

Auditory icons
One of the most famous examples of auditory icons is the SonicFinder developed
for Apple. The SonicFinder was developed as an alternative to the Macintosh Finder
(equivalent to Explorer in MS Windows). The SonicFinder used sound in a way that

Chapter 13 • Multimodal interface design

reflects how it is used in the everyday world. Users were able to ‘tap’ objects in order to
determine whether they are applications, disks or folders, and it was possible to gauge
their size depending upon how high-pitched they sounded (small objects sounded highpitched while large objects sounded low-pitched). Movement was also represented as a
scraping sound.

The term ‘soundscape’ is derived from ‘landscape’ and can be defined as the auditory
environment within which a listener is immersed. This differs from the more technical
concept of ‘soundfield’, which can be defined as the auditory environment surrounding
the sound source, which is normally considered in terms of sound pressure level, dura­
tion, location and frequency range.

Challenge 13.3
We u se b a c k g r o u n d s o u n d to a s u rp ris in g d e g re e in m o n ito rin g o u r in te ra c tio n w ith th e
w o rld a r o u n d us. F o r e x a m p le , I k n o w t h a t m y la p to p is s till w ritin g to a C D b e c a u s e it
m a k e s a s o r t o f w h irrin g so u n d . I f m y s e m in a r g r o u p a re w o rk in g o n p r o b le m s in s m a ll
g ro u p s, a ru stlin g o f p a p e rs a n d q u ie t- ish m u rm u rin g in d ic a te s a ll is w e ll, c o m p le te
s ile n c e m e a n s t h a t I h a v e b a ffle d p e o p le , a n d lo u d e r c o n v e rs a tio n o fte n m e a n s th a t m o st
h a v e fin is h e d . A t h o m e , I c a n te ll t h a t th e c e n tr a l h e a tin g is w o rk in g a s it s h o u ld b y th e
b a c k g r o u n d n o ise o f th e b o ile r (fu r n a c e ) a n d th e a p p ro x im a te tim e d u rin g th e n ig h t b y
th e v o lu m e o f t r a ffic n o ise fr o m th e ro a d .
M a k e a s im ila r - b u t lo n g e r - list fo r y o u rs e lf. It m ig h t b e e a s ie r to d o th is o v e r a c o u p le
o f d a y s a s y o u n o tic e so u n d s. R e a d o v e r y o u r list a n d n o te d o w n a n y id e a s fo r u sin g s o u n d
in a s im ila r w a y in in te ra c tio n d e sig n .


An important issue in designing for sound is that of discrimination. While it is easy to
talk about discriminating between low- and high-pitched tones, it is quite another to
discriminate between quite low and fairly low tones. There are a number of open ques­
tions about how well we can distinguish between different tones in context (in a busy
office or a noisy reception area) and this is made worse by the obvious fact that sounds
are not persistent. One of the strengths of the graphical user interface is the persistence
of error messages, status information, menus and buttons. Auditory user interfaces are,
in contrast, transient.

Speech-based interfaces
Speech-based interfaces include speech output and speech input. Speech output has
developed over the past few years into a robust technology and is increasingly common
in such things as satellite navigation systems in cars (‘satnavs’) and other areas such as
announcements at railway stations, airports, etc. Speech output uses a system that con­
verts text to speech, TTS. Sounds are recorded from an individual and are then stitched
together through the TTS to create whole messages. In some places TTS is becoming
so ubiquitous that is gets confusing hearing the same voice in different locations. The
woman telling you something at a railway station is the same woman advising you on
your satnav system. TTS systems are readily available and easy to install into a system.
They have gone beyond the robotic-type voices of the last decade to produce realistic
and emotionally charged speech output when required.



Part II

Techniques for designing interactive systems

Speech input has not quite reached the level of sophistication of speech output, but it
too is becoming a technology that has reached levels of usability such that the interac­
tion system designer can now consider it to be a real option. The best systems require
people to train the automatic speech recognizer (ASR) to recognize their particular
voice. After only 7-10 minutes of training an ASR can achieve recognition levels of
95 per cent accuracy. This paves the way for natural language systems (NLS) where
people can have conversations with their devices. There are still many obstacles to over­
come in NLS - it is one thing to understand the speech, it is another to understand what
the person means by what they are saying. But in limited domains, where dictionar­
ies can be used to help disambiguate words, they are starting to make a real impact.
In 2011 Apple introduced a speech-based ‘personal assistant’ called Siri to the iPhone
which can carry out simple tasks such as sending a text message or finding out informa­
tion. It has met with a mixed reception, sometimes appearing to be quite impressive and
sometimes being very stupid!

13.4 Tangible interaction

-> Haptic perception is
covered in Chapter 25

Tangible means being able to be touched or grasped and being perceived through the
sense of touch. Tangible interaction is a practical application of haptics and has been
used for thousands of years (Figure 13.8). Tangible interaction has given rise to TUIs tangible user interfaces, which have a structure and logic both similar to and different
from GUIs. With the introduction of multi-touch displays, TUIs promise to be increas­
ingly important as they lead to interaction through physical objects and through gesture

Fig u re 13.8 An abacus, which combines tangible input, output and the data being
(Source: Courtesy of Sphere Research Corporation)

Most of the work to date has been confined to the major research laboratories, for
example the Media Lab at MIT, which have constructed advanced prototype systems.
Many of these systems have been used in fairly specific domains, for example urban
planning (Urp) and landscape architecture among others. Illuminating Clay is described
in detail below. While many of these systems may never become commercial products,
they do illustrate the state of the art in tangible interaction design.
The Tangible Media Lab at MIT describe their vision for the future of HCI in the fol­
lowing way:
Tangible Bits is our vision of Hum an C om puter Interaction (H C I) w hich guides our research
in the Tangible M edia Group. People have developed sophisticated skills for sensing and

Chapter 13 • Multimodal interface design
m anipulating our physical environm ents. However, most of these skills are not em ployed
by traditional GUI (G raphical User Interface). Tangible Bits seeks to build upon these skills
by giving physical form to digital in fo rm atio n , seam lessly co upling the dual w o rld s of
bits and atoms. Guided by the Tangible Bits vision, w e are designing 'tangible user inter­
faces' w h ich em ploy physical objects, surfaces, and spaces as tangible em bodim ents of
digital info rm atio n. These include foreground interactions w ith graspable objects and
augmented surfaces, exploiting the human senses of touch and kinesthesia. W e are also
exploring background inform ation displays w h ich use 'am bient m edia'- am bient light,
sound, airflow, and w ater m ovem ent. Here, w e seek to com m unicate digitally-m ediated
senses of activity and presence at the periphery of human awareness.

So their ‘goal is to change the “painted bits” of GUIs (graphical user interfaces) to “tan­
gible bits”, taking advantage of the richness of multimodal human senses and skills
developed through our lifetime of interaction with the physical world’.

Why tangible interaction?
There are a num ber of good reasons w h y w e should think about adopting (o r at least


exploring the possibilities of) tangible interaction. First of all, if w e could rem ove the
divide between the electronic and physical w orlds w e potentially have the benefits of
both. W e could have all the advantages of com putation brought to us beyond the co n­
fines o f the graphical display unit and have them , as it were, present-to-hand. Present-


to-hand could also be taken literally by putting inform ation and com putation literally
'in our hands' (we are, after all, discussing tangible interaction). Finally, and this is prov-


ing to be a recurrent them e in this chapter, there m ay be advantages in off-loading
some of the burden of our com putation (thinking and problem solving) by (a) accessing
our spatial cognition and (b) adopting a more concrete style o f interaction (like sketch­
ing, w hich provides a m ore fluid and natural style of interaction). Graspable, physical
objects provide stronger (real) affordances as com pared to th eir virtual equivalents.

Hiroshi Ishii is one of the key people at MIT and a leading light in the world of tangible
computing. He notes that
TUIs couple physical representations (e.g. spatial m anipulable physical objects) with digital
representations (e.g. graphics and audio), yielding interactive systems that are com puta­
tionally mediated but generally not identifiable as 'computers' per se.
Ullmer and Ishii (2002)

In plain English, if we want to use an on-screen, virtual tool - say a pen - we would use
a real, physical pen which in some sense has been mapped onto the virtual equivalent.
Picking up the real pen would then be mirrored in the computer by the virtual pen being
raised or becoming active. Drawing with the real pen would result in an equivalent vir­
tual drawing which might be displayed on a screen and represented as a data object.
TUIs are different from GUIs in many different ways, but here are three important
• TUIs use physical representations - such as modelling clay, physical pens and so on
and physical drawing boards rather than pictures of them displayed on monitors. So,
for example, instead of having to manipulate an image on a screen using a mouse and
keyboard, people can draw directly onto surfaces using highlighter pens.



Part II • Techniques for designing interactive systems

• As these tangible, graspable elements cannot, of course, perform computation on
their own, they must be linked to a digital representation. As Ullmer and Ishii put it,
playing with mud pies without computation is just playing with mud pies.
• TUIs integrate representation and control which GUIs keep strictly apart. GUIs
have an MVC structure - Model-View-Control. In traditional GUIs we use periph­
eral devices such as a mouse or keyboard to control a digital representation of what
we are working with (the model), the results of which are displayed on a screen or
printer or some other form of output (the view). This is illustrated in Figure 13.9.

Fig u re 13.9 M od el-V iew Control

TUIs in contrast have a more complex model that can be seen in Figure 13.10. This
is the MCRpd model. The control and model elements are unchanged but the view
component is split between Rep-p (physical representation) and Rep-d (digital repre­
sentation). This model highlights the tight linkage between the control and physical
representation. This MCRpd model is realized in the prototypes described in the sec­
tion below.

Fig u re 13.10 MCRpd

Illuminating Clay
Illuminating Clay is an interesting, though specialist, example of tangible computing.
Illuminating Clay is introduced and placed in context by its creators with the following
A group of road builders, enviro n m en t engineers and landscape designers stand at an
ordinary table on w hich is placed a clay model of a particular site in the landscape. Their
task is to design the course of a new roadway, housing com plex and parking area that will
satisfy engineering, environm ental and aesthetic requirem ents. Using her finger the engi­
neer flattens out the side of a hill in the model to provide a flat plane for an area for car
parking As she does so an area o f yellow illum ination appears in another part of the model.

Chapter 13 • Multimodal interface design
The environm ental engineer points out that this indicates a region o f possible landslide
caused by the change in the terrain and resulting flo w o f water. The landscape designer
suggests that this landslide could be avoided by adding a raised earth mound around the
car park. The group tests the hypothesis by adding m aterial to the model and all three
observe the resulting effect on the stability of the slope.

et al. (2002)

In the Illuminating Clay system, the physical, tangible objects are made of clay. Piper
etal. (2002) experimented with several different types of modelling material, including
Lego blocks, modelling clay, Plasticine, Silly Putty and so on. Eventually they found that
a thin layer of Plasticine supported by a metal mesh core worked best. This clay was
then shaped into the desired form by the landscape specialists (see Figure 13.11). The
matte white finish also proved to be highly suitable as a projection surface onto which
the digital elements of the system were projected. Ordinarily, people working with land­
scapes would create complex models using computer-aided design (CAD) software and
then run simulations to examine, for instance, the effects of wind flow, drainage and the
position of powerlines and roads. With Illuminating Clay, the potential consequences of
the landscape are projected directly (for example, as in the scenario above, a patch of
coloured light) onto the clay itself.
The coupling between clay and its digital representation is managed by means of a
ceiling-mounted laser scanner and digital projector. Using an angled mirror, the scan­
ner and projector are aligned at the same optical origin and the two devices are cali­
brated to scan and project over an equal area. This configuration ensures that all the
surfaces that are visible to the scanner can also be projected upon.
Thus Illuminating Clay demonstrates the advantages of combining physical and
digital representations for landscape analysis. The physical clay model conveys spa­
tial relationships that can be directly manipulated by the user’s hands. This approach
allows users to quickly create and understand highly complex topographies that
would be time-consuming using conventional computer-aided design (CAD tools).

Fig u re 13.11 An image from Illuminating Clay
(Source: Piper, B., Ratti, C. and Ishii, H. (2002) Illuminating Clay: a 3D tangible interface for landscape analysis. Proceedingsof
theSIGCHI ConferenceonHumanFactorsinComputingSystems: Changingourworld, changingourselves, Minneapolis, MN.
20-25 April, CHI '02 ACM, pp. 355-62. © ACM. Inc. Reprinted by permission. http://doi.acm.Org/10.1145/503376.503439)

Challenge 13.4
S u g g e s t o th e r a p p lic a tio n a re a s w h e re Illu m in a tin g C la y m a y b e u se fu l.



Part II • Techniques for designing interactive systems

r ................—... ........

■ .....................................

I. .


-.................... ...

13.5 Gestural interaction and surface computing
With the arrival of multi-touch surfaces - table tops, sm artphones, tablets and
interactive walls that recognize multiple touch points - a whole new era of inter­
action design is just beginning. A number of sessions at the CHI2009 conference
were devoted to exploring these issues. The iPhone introduced gestures for ‘mak­
ing things bigger’ (pinch with two fingers and draw them out) and ‘making things
smaller’ (touch an object with two fingers and draw them in) (see Table 13.1).
Experimental systems such as CityWall (http://cityw introduced gestures
for rotating objects, ‘flicking’ gestures to move objects from one location to another.
Fiebrink et al. (2009) gave people the option of designing gestures, or using virtual
controls on a tabletop application for collaborative audio editing. However, we are
still some way from having the type of standard widgets that we see in GUIs. Different
applications demand different types of gesture according to the different activi­
ties that people are engaged in. Interactive surfaces can be interacted with through
direct touch, sweeping movements, rotation and flicking, which can be mapped onto
specific functions. Interaction can also take place using physical objects that repre­
sent functions, or other objects. Similar to earcons these have been called ‘phicons’.
Combinations of phicons, virtual on-screen buttons, slides and other widgets and
natural gestures (such as a tick gesture for ‘OK’, or a cross gesture for cancel) promise
to open up new applications and new forms of operating system that support differ­
ent gestures.
Table 13.1

iOS gestures

G e stu re

A c tio n


To press or select a control or item (analogous to a single mouse click).


To scroll or pan (that is, m ove side to side).
To drag an elem ent.


To scroll or pan quickly.


W ith one finger, to reveal the Delete button in a table-view row, the
hidden view in a split view (iPad only), or the Notification Center
(from the top edge o f the screen).
W ith four fingers, to switch between apps on iPad.

Double tap

To zoom in and center a block o f content o r an image.
To zoom out (if already zoom ed in).


Pinch open to zoom in.
Pinch close to zoom out.

Touch and hold

In editable or selectable text, to display a magnified view for cursor


To initiate an undo or redo action.


Chapter 13 • Multimodal interface design

In Windows 8 there are a number of standard gestures for use with touchscreen
devices. A swipe from the right-hand side of the tablet to the left brings up the ‘charms’
menu, which includes icons for Search, Share, Devices, Settings and Start Screen. A
swipe from the left brings a list of the apps that are currently running, whereas a slow
swipe from the left lets people select an app and position it on the main screen. Windows 8
has gestures for making things larger and smaller and right and left swipes will move
between objects such as different sites on Internet Explorer. At the Start Screen, you can
swipe down on any tile to select it and bring up additional options.
Surface computing brings its own set of design issues. Orientation has always been
an issue in collaborative tabletop workspaces because when people are seated at differ­
ent locations around a table, they will see the same object with different orientations.
This affects comprehension of information, coordination of activities, and communica­
tion among participants. Different tabletop systems have found different solutions to
this issue. Some systems use one single and fixed orientation where the participants
have to sit side-by-side. Some systems use an automatic orientation of artefacts towards
the people in the workspace, or use an automatic rotation of the workspace. However,
most systems just let participants manually orient digital objects. Various techniques
have been developed to facilitate orientation. Dragging and spinning artefacts in the
workspace using fingers is one; another consists of a translation by clicking and drag­
ging a digital object and a rotation by selecting, touching a corner, and then turning the
object around an axis located at the centre of it (Kruger e ta l, 2005).
There are a number of user interface issues specific to multi-touch interaction. The
‘fat fingers, short arms’ problem is just one. Fingers limit the precision of any input
gesture such as touching or dragging. Thus, interface objects should have a minimum
size, should not be close together and feedback should be given when people succeed in
hitting the target (Lei and Wong, 2009; Shen et al, 2006). Similarly short arms mean
that targets must be relatively close to people. For example there is no point in having a
menu at the top of a screen if people cannot reach it! Another problem is screen occlu­
sion. When people interact with the interface their hands can occlude a part of the inter­
face, especially the part immediately below what they are interacting with. To avoid this
problem objects should be large, or gestures should be performed with only one finger
(where the palm can be slanted) instead of spreading five fingers (Lei and Wong, 2009).
Additionally, information such as a label, instructions or sub-controls should never be
below an interactive object (Saffer, 2008).
Shen et al. (2006) developed two systems to avoid this occlusion. The first was an
interactive pop-up menu that is able to rotate, linked to an object and which can be
used for displaying information or performing commands, and the second a tool allow­
ing people to perform operations on distant objects. Another UI issue is that when
people perform actions, they might lead to unexpected activation of functionality
(Ashbrook and Starner, 2010) such as if the surface records a false positive touch or
gesture recognition for example, if someone’s sleeve touches the surface as they reach
over. Thus the system needs ways to differentiate an intentional gesture from an unin­
tentional gesture.
Saffer (2008) provides good sound advice on gesture design coming from ergonomic
principles such as ‘avoid outer position, avoid repetition, relax muscles, utilize relaxed
and neutral positions, avoid staying in a static position, and avoid internal and external
force on joints’. He also warns us to consider fingernails, left-handed users, sleeves and
gloves in the design of multi-touch interfaces. On large multi-touch tables, some parts
of the display can be unreachable, thus, objects like menus, tools and work surface have
to be mobile.



Part II • Techniques for designing interactive systems


We described the design of a multi-touch tabletop application
later (Chapter 16). However, on another project we were devel­
oping we realized that there was no standard gesture for ‘open a
browser’. We explored a number of options such as drawing a circle
(‘o’ for open), but the problem here was that different people draw
circles in different ways. We tried drawing a square. Just touching
the surface led to a large num ber of false positives when the sys­
tem detected a touch that was not intended to be an open-a-browser
command. Finally we settled on the gesture shown in Figure 13.12
(‘N’ for new) because most people draw an ‘N’ from left to right and
bottom to top and hence the system could detect the required orien­
tation of the browser.
Fig u re 13.12 The N-wave gesture to
Surface computing does not just relate to flat surfaces such as tab­
open a browser; the red and black
letops, tablets and walls. Flexible displays are already being developed
circles give feedback on the user's
which can be produced in different shapes, and other materials such
as fabrics can be used as interactive devices. These developments will
We discuss different
once again change the issues for interaction design.
materials in Chapter 20
For example Pufferfish (Figure 13.13) makes large spherical displays and new OLED
(organic light-emitting diode) technologies are allowing for curved and flexible dis­
plays. These bring new forms of interaction to the world of interaction design.
Gestural interaction does not always mean that users have to touch a surface. Sensors
may detect different levels of proximity of people, or hands and can interact based on
this information. The Kinect detects distant movement, allowing people to interact with
content from a distance. In short, all manner of new forms of interaction with gestures
and surfaces will appear in the next few years.

Fig u re 13.13 An interactive PufferSphere M600 which w as used as part of the 'Audi
Spheres' experience in Copenhagen July/August 2012, httpV/www.pufferfishdisplays
(Source; Courtesy Pufferfish Ltd.)

Chapter 13 • Multimodal interface design

Haptics meets hearing
A new mobile phone has just been announced which requires the user to put their
finger into their ear. The Japanese telecoms company NTT DoCoM o has developed a
wearable mobile phone that uses the human body to make calls. Called Finger Whisper,
the device is built into a narrow strap worn on the wrist like a watch. To answer a call on
the Finger Whisper phone, to make a call or hang up, the user simply touches forefinger
to thumb and then puts their forefinger in their ear. Electronics in the wristband convert
sound waves into vibrations, which are carried through the bones of the hand to the
ear so that the Finger Whisper user can hear the other caller. A microphone in the wrist­
band replaces the cell phone's usual mouthpiece, and instead of dialling a number, the
user says it out loud. Voice recognition technology turns the command into a dialled
number. The company said it was too early to say when the Finger Whisper phone
might go on sale. However, it should be noted that the prototype is currently the size of
a kitchen cupboard.

Summary and key points
T h ere is no do u b t th at sound, to u ch and m ixed reality w ill play an im p o rtan t role in the
design o f fu tu re interactio ns. A cross the spectrum o f virtu al w o rld s m ixing w ith the real
w orld are o p p o rtu n ities fo r new and novel exp eriences. T h e w o rk w h ich has been carried
out to m ake sound useful and usable at the interface is co n vin cin g but still has not been
adopted by the m ajo r user interface designers. T U Is offer a n ew w a y o f th in kin g ab o u t and
interacting w ith co m p uters. W h ile the keyboard and m o use o f the typical PC o ffer a tan g i­
ble interface, true T U Is em b o d yin g the M CRpd m odel are still o n ly available as advanced
prototypes. Finally, gestural interactio n w ill evo lve rapidly o ve r the next few years.

E x e rc is e s

Design a sonically enhanced interface for a s im p le game in the form of a
general knowledge quiz for children. The quiz is presented as a set of multiplechoice questions. If time is short, confine yourself to one screen of the game.
This is much m ore fun done in presentation software such as PowerPoint or
any of the m ultimedia software packages if you are familiar with them.


Discuss the advantages and disadvantages of augm enting the user interface
with (a) sound and (b) haptics. In your view, w hich has m ore potential and
w hy? Support your argument with specific examples.

..............................................................................................................................................................................................................- ------- ---------------------------------------------------------------------------------

Further reading
Ullmer, B. and Ishii,

H. (2002) Emerging frameworks for tangible user interfaces. In Carroll,

J.M. (ed.), H u m a n - C o m p u te r In te ra c tio n in th e N e w M ille n n iu m . ACM Press, N ew York. A
u se fu l in tro d u c tio n to th e ta n g ib le s d o m a in .




Part II • Techniques for designing interactive systems

G etting ahead
B la u e rt.J. (1999) S p a t i a l H e a r in g . M IT Press, Cam bridge, MA.

The M edia Lab is a good place to start looking for exam ples of mixed reality and m ultimodal
systems. See w w w .m it.ed u
The accom panying website has links to relevant websites. Go to

Comments on challenges


Challenge 13.1
Here are three possibilities. There are, of course, many more. All would need careful design.
1 Voice read-out of calendar reminders.

Different audio tones to distinguish levels in the file system hierarchy.
Read-out of senders and first lines of incoming e-mail, so one could do other physical jobs
around the room while listening to a new batch of messages. Even better with voice command

Challenge 13.2
It can be a fascinating experience to attend to the usually unconscious use we make of sound. For
example, an ATM does not have to make a noise as it counts out the money, but it is reassuring for
people to know that the transaction is nearly complete. In fact lots of machines - kettles, drinks
machines, cars, bikes and so on - indicate the state they are in through the sounds they make.

Challenge 13.3
The list you produce will be individual to you and your circumstances. An idea which comes to
mind is attaching an unobtrusive humming to a file search or other lengthy operations, perhaps
changing in pitch as it nears completion.

Challenge 13.4
Any area where the design of physical objects has to be checked for particular properties or against
guidelines is a possibility. One might be the design of car bodies, which - at least until relatively
recently - are 'mocked-up' full-size in order to check for wind resistance, etc. Designers make mod­
ifications to the mock-up by hand and then check in a wind tunnel.


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Part III
Contexts for designing
interactive systems
14 Designing w e b site s 310
15 Social m edia 341
16 Collaborative environm ents 363
17 Agents and a vatars 385
18 Ubiquitous com puting 410
19 M obile com puting 435
20 W earab le com puting



Part III • Contexts for designing interactive systems

Introduction to Part III
In this part w e look at a n u m b e r o f d ifferen t co ntexts in w h ich in teractive system s design
takes p lace. T h e first o f th ese is w e b site design. T h e aim o f C h a p te r 14 is to p ro vid e
a p ractical ap p ro a ch to w e b site d e v e lo p m e n t. W e b site d e v e lo p m e n t n eeds to take a
h u m an -cen tred ap p ro ach ju s t as o th e r in teractive system s do, so it is n ecessary to aug­
m en t the app ro ach d escrib ed w ith the p rin cip le s and practices o f good design discussed
in Part I and e m p lo yin g th e te ch n iq u e s d escrib ed in Part II. C h ap te r 15 co vers the p artic­
ular use o f w eb sites and m o b ile ap p licatio n s fo r so cial m ed ia w h ic h e m p h asizes people
w o rk in g to g eth er and sh arin g digital co n te n t.
C h a p te r 16 co vers C o m p u te r S up p orted C o o p e rativ e W o rkin g (C S C W ) and co lla b o rative
e n v iro n m e n ts - p a rtic u la rly th o se m akin g use o f m u ltito u ch surfaces. M an y o rg a n iz a ­
tio ns are realizin g th at th e y need to m ix te ch n o lo g ies and the design o f e n viro n m e n ts
to enco urag e c re a tivity and effective co lla b o ratio n . T h e d em an d s o f these e n viro n m e n ts
are co vered here.
C h ap te r 17 deals w ith a n o th e r e m erg ing area fo r designers, ag ent-based in teractio n . W e
are in cre a sin g ly d eleg atin g a c tiv itie s to a rtificia l e n titie s th a t do th in g s on o u r behalf:
agents. S o m etim e s th ese agents take on a fo rm o f e m b o d im e n t such as an o n -screen
avatar, o r as a ro b o tic character. C h a p te r 17 is ab o u t agents and avatars and h o w th ey
p ro vid e a d istin ctiv e c o n te x t fo r in te ra ctiv e system s design. T h e stru ctu re o f agents is
discussed alo n g w ith issues o f ju s t h o w d ifficu lt it is to m ake sensib le inferen ces from the
lim ited data th at in teractive d e vices have access to.
C h ap ters 18 and 19 deal w ith tw o hig hly in tertw in e d co ntexts: u b iq u ito u s co m p u tin g and
m o b ile co m p u tin g . U biq u ito u s m eans e ve ryw h e re and co m p u te rs are e v e ryw h e re partly
becau se th ey are m o b ile, so design issues o f th e o n e get m ixed w ith design issues o f the
other. H ow ever, the tw o chap ters deal w ith things in a slig htly d iffe re n t w ay. C h a p te r 18
deals w ith th e m o re th e o re tica l issues o f u b iq u ito u s co m p u tin g an d w ith th e ideas o f
in fo rm a tio n sp aces an d h o w th e y can be su cce ssfu lly n avig ated . C h a p te r 19 is m o re
practical, d iscussing h o w to design fo r sm all, m o b ile devices and takin g readers through
th e design process as app lied to m o b ile d evices.
Finally, C h ap te r 20 intro d u ces th e n ew co n text o f w ea ra b le co m p u tin g . T h e em erg ence
o f in teractive fab rics m eans th at peop le can n o w w e a r th e ir co m p u te rs instead o f c a rry ­
ing th em ! In C h ap te r 20 w e look at th e state o f the art in w ea ra b le co m p u tin g and w h e re
it m ay go o ve r the n ext fe w years.

Case studies
C h a p te r 14 p rese n ts an e x a m p le o f w e b site desig n, th e design o f th e R o b e rt Lo u is
Ste ven so n w e b site . T h is p ro je ct illu strate s m a n y o f th e issues th at all W e b d esig ners
face. C h ap te r 16 d escrib es o u r exp e rie n ce s in d e velo p in g a m u ltito u ch tab le ap p licatio n
fo r th e N orw eg ian N atio nal M useum and h o w te ch n o lo g ie s an d activ itie s fit to g eth er
to fa cilita te c o lla b o ra tio n , in clu d in g a stu d y o f th e Lo n d o n U n d erg ro u n d . C h a p te r 17
inclu des a case stu dy o f an e-m ail filterin g ag ent. C h ap ters 18 and 19 d ra w upon so m e
rece n t p ro je ct w o rk th at w e have been in vo lved w ith , kno w n as Speckled C o m p u tin g .
T h is is an e xa m p le o f a w ire le ss se n so r n etw o rk (W S N ) co n sistin g o f p o te n tia lly th o u ­
sands and th o usan d s o f tiny, p o ssib ly m o b ile d evices. Scattered o ve r a physical area th ey

Introduction to Part III
create a cyb e r-p h ysica l system . Th is is th e sort o f co n te xt th at the near fu tu re holds. In
o rd e r to m ove through this space req uires a m o b ile d evice.

Teaching and learning
Th is part co n tain s seven d ifferen t co ntexts th at have sp e cific req u ire m e n ts fo r in te ra c ­
tion design. T h u s each ch a p te r can be stu died as an exa m p le and used to e xp lo re the
design processes and te ch n iq u e s discussed in Parts I and II. T h e list o f to p ics co vered in
this part is sho w n below , each o f w h ich could take 1 0 -1 5 hours o f stu dy to reach a good
general level o f u n d e rstan d in g , o r 3 -5 h ou rs fo r a b asic ap p re cia tio n o f th e issues. O f
co urse, each to p ic co uld be the su b ject o f e xten sive and in-d epth study.
To pic 3.1

W ebsite design

Topic 3.2

In fo rm atio n arch ite ctu re

Topic 3.3

N avigation design fo r w ebsites

Topic 3.4

Social m ed ia

To pic 3.5

Future Internet

To pic 3.6

C o o p erative w o rk in g

Section s 1 4 .1 -1 4 .2 ,1 4 .5
Section 14.3
Section 14.4
Section s 1 5 .1 -1 5 .4
Section 15.5
Section s 1 6 .1 -1 6 .3
Section 16.4

To pic 3.7

C o lla b o ra tive e n viro n m e n ts

Topic 3.8

Agent-based interactio n

Topic 3.9

A d ap tive system s

Section 17.2

To pic 3.10

Em bo died co n ve rsatio n al agents

Section 17.5

To pic 3.11

U biq u ito u s co m p u tin g

To pic 3.12

In fo rm atio n spaces

Section 18.2

Topic 3.13

Blended spaces

Section 18.3

Topic 3.14

H o m e e n viro n m e n ts

Section 18.4

To p ic 3.15

N avigation care stu d y sectio n s

To p ic 3.16

C o n text-aw are co m p u tin g

Topic 3.17

M o b ile co m p u tin g

To p ic 3.18

W e a ra b le co m p utin g

Section s 17.1, 1 7 .3 -1 7 .4

Section s 1 8 .1 ,1 8 .5

Section s 1 8 .5 ,1 9 .5
Section s 19.2, 19.5
Section s 1 9 .1 ,1 9 .3 - 1 9 .4
C h a p te r 20


Chapter 14
D esigning w eb sites




Introduction 311

O n e o f th e m o st lik e ly th in g s th a t in te ra c tiv e sy ste m d e sig n e rs w ill


W ebsite developm ent 312

d e sig n is a w e b s ite . T h e re a re d o z e n s o f b o o k s o n w e b s ite d e sig n ,


The inform ation architecture
of websites 318

all o ffe rin g a d v ic e , b u t s o m e a re m o re fo c u se d o n th e u s a b ility an d


Navigation design for
websites 328
Case study: designing the
Robert Louis Stevenson
website 331

Sum m ary and key points 339
Exercises 339

e x p e rie n c e th a n o th e rs. A lb e rt B a d re (2 0 0 2 ) id e n tifie s fo u r m ain g e n re s
o f w e b s ite s : N e w s, S h o p p in g , In fo rm a tio n an d E n te rta in m e n t. Each
o f th e se h as se v e ra l su b -g e n re s (fo r e x a m p le , N e w s h as B ro a d c a st
T V , N e w s p a p e r a n d M a g a z in e ), a n d w ith in a g e n re c e rta in desig n
fe a tu re s a re c o m m o n . F o r e x a m p le , s h o p p in g site s w ill h a v e a fill-in
fo rm to c o lle c t d a ta o n d e liv e ry a d d re ss an d p a y m e n t d e ta ils; n e w s
site s m u st p ay s p e c ia l a tte n tio n to th e p re s e n ta tio n o f te xt. T h e g e n re s
a lso h a v e d iffe re n t w a y s o f a rra n g in g th e c o n te n t. N e w s site s w ill h ave

Further reading 339

lo n g s c ro llin g p ag es w h e re a s s h o p p in g sites w ill h a v e s h o rt pages.

W eb links 340

C o m b in a tio n site s are , o f c o u rse , c o m m o n . F o r e x a m p le , a site fo r

Com m ents on challenges 340

b o o k in g p la n e flig h ts w ill o fte n h a v e a n e w s site a s so c ia te d w ith th e
d e s tin a tio n .
In th is c h a p te r w e d istil th e b e st a d v ic e fro m th e w o rld 's b e st w e b s ite
d e sig n e rs, lo o k in g a t issues re le v a n t to all m a n n e r o f w e b s ite s . A fte r
s tu d y in g th is c h a p te r y o u s h o u ld be a b le to :

U n d e rsta n d h o w to a p p ro a c h w e b s ite d esig n an d th e stag es yo u
n ee d to go th ro u g h


U n d e rs ta n d th e im p o rta n c e o f in fo rm a tio n a rc h ite c tu re


U n d e rs ta n d h o w to d esig n fo r n a v ig a tio n in w e b s ite d e sig n .

Chapter 14 • Designing websites

14.1 Introduction
The development of a website involves far more than just its design. There are a lot
of pre-design activities concerned with establishing the purpose of the site, who it
is aimed at and how it fits into the organization’s overall digital strategy. In larger
organizations there will be plenty of disagreement and arguments about all these
issues and these internal politics often affect the final quality of the site. Many sites
finish up as too large, trying to serve too many issues with the marketing people in
charge; usability and engagement come a long way down the list of priorities. At the
other end of the process the launch of the site has to be carefully managed and other
infrastructure issues will need to be addressed, such as how, when and by whom the
content is written and updated, who deals with e-mails and site maintenance, and
so forth.
In the middle of these two is the part that interests us - the design and develop­
ment of a site that is effective, learnable and accommodating. This includes developing
the structure of the site: the information architecture. Website design is also concerned
with information design (discussed in Chapter 12) and, importantly, with navigation
Some example websites are shown in Figure 14.1.

Fig u re 14.1 Exam ples of w ebsites: (a) Shopadidas; (b) edutopia; (c) whitevoid
(Source: (a); (b); (c)



Part III • Contexts for designing interactive systems

Writing content
Vital to the success o f a website, of course, is the content. In website design the designer
has to acquire ano ther skill - that o f w riting and organizing inform ation co ntent. In
m any organizations som eone else might w ork w ith the designer to help. M any w e b ­
sites are seriously overloaded w ith content and try to serve too m any different types of
customer. A university w ebsite w ill often try to cater for potential students, existing stu­
dents, academ ic staff, adm inistrative staff (its own and from other universities), business
partners and so on. Trying to accom m odate all these different user groups results in an
unruly and ram bling site, m aking it difficult for any one of these groups to be satisfied.
The sam e is true o f large corporation and public service sites. A detailed PACT analysis
and developing personas w ill help to identify the needs o f different user groups.
.................................................................... -................. -.......--..............-.............................................. ..........................

Websites are implemented either using the mark-up language, HTML5, and the asso­
ciated page layouts described in Cascading Style Sheets (CSS) or using a content
management system (CMS). There are a variety of CMSs readily available with the
most popular being WordPress. Other more sophisticated CMSs include Joomla! and
Drupal. It is also important to understand that a website is part of the global World
Wide Web, so if designers want the site they are designing to be found by other peo­
ple, they will need to make it stand out. This involves adding features that will enable
search ‘engines’ such as Google to index the site. The art of search engine optimiza­
tion (SEO) is somewhat mysterious, but basically involves adding m etadata to the
site and getting the information architecture of the site right. This is discussed in
Section 14.3.

14.2 Website development
The design of websites should follow the principles of good interaction design that have
been outlined previously. Designers need to know who is going to use the site and what
they are going to use it for. Websites need to be well focused with clear objectives. They
should develop personas of the people whom they expect to be visiting the site and
understand clearly what goals they will have when using the site. The design phases of
understanding, envisionment, design and evaluation need to be undertaken. Scenarios
of use should be developed, prototyped and evaluated.
Even if a site is well focused, it will soon get large and so issues of how to move
around a website become important; navigation is a central concern here. Support to
enable people to discover the structure and content of the site and to find their way
to a particular part of the site is the key issue. Information architecture is an area of
study devoted to designing websites and helping people to answer questions such as:
Where am I? Where can I go? Where have I been? What is nearby? Navigation bars at
the top and down the side of the Web pages will help people develop a clear overall
‘map’ of the site.
It is also vital to pay attention to the design principles outlined in Chapter 4.
Consistency is important and a clear design language should be developed, including
interaction patterns for the main recurring interactions. If it is not desirable to use the
standard blue underlined links then ensure that links are consistent so that people will
quickly learn them. Many sites confuse people by not making links sufficiently visible
and distinguishable from other text in the site.

Chapter 14 • Designing websites

Provide people with feedback on where they are in the site and clarify contexts and con­
tent. Using meaningful URLs (uniform resource locators, i.e. Web addresses) and familiar
titles will help people find what they are looking for and understand what other content is
in the site. A good design guideline for websites is to minimize the need for scrolling and
plan for entry at (almost) any page, as not all your visitors will go in through the front page.
In general there is a trade-off between designing pages for people who have just
arrived there and people who have followed the navigational structure. Having a link
to the ‘home’ (front) page of a site in a prominent position and having a site map will
enable people to orient themselves.
The site’s home page is particularly important and should feature a directory, a
summary of important news/stories and a search facility. Ensure that it is clear what
has been searched when designing the search facility. Different people have differ­
ent strategies on websites. Half of all site visitors are ‘search-dominant’, 20 per cent
‘link-dominant’ and the rest mixed (Nielsen, 1993). Search-focused people are taskcentred and want to find what they want, whereas others are happy to browse around.
Jesse James Garrett (Garrett, 2003) conceptualizes the development of a website in
terms of five elements: strategy, scope, structure, skeleton and surface (Figure 14.2).
• The bottom layer is the ‘strategy plane concerned with understanding the overall
objective of the website, the nature of the people who will be using the site and what
their requirements of the site are. Strategy is concerned with business goals, the
organization’s brand and a market analysis.



Fig u re 14.2 Elements of user experience
(Source: The Elements of User Experience: User-centeredDesignfor theWeb(Garrett, J.J. 2003) © 2003 Jesse James
Garrett, reproduced by permission of Pearson Education, Inc. publishing as New Riders Publishing, all rights reserved)



Part III • Contexts for designing interactive systems

• The next layer is the ‘scope’ plane where the emphasis is on functionality (what the
site will let people do) and on content (the information the site will hold). He argues
that spending time on the scope plane is important so that Web designers know what
they are designing and what they are not designing! The result of scoping the site is a
clear, prioritized set of requirements.
• The third layer is called the ‘structure’ plane. It covers information architecture but
also includes specifying the interaction design. The key feature here is to establish a
clear conceptual model.
• The ‘skeleton’ plane is concerned with information design, navigation design and
interface design.
• The final element of Garrett’s scheme is the ‘surface’ plane, concerned with the
aesthetics of the site and with ensuring that good design guidelines are followed.
For example, links should look like links and things that are not links should not!

<- Wi ref rames are

discussed in Chapter 8

Garrett advocates using a simple graphical ‘language’ to map out the information archi­
tecture of a website. The key elements of the language are a representation of pages,
files, and stacks of pages and files. These are structured into site maps, showing direction
of links if appropriate. Garrett also employs other symbols to represent decisions (a dia­
mond shape), forbidden routes (a cross-bar) and other key concepts. A full explanation
can be found at Garrett’s website. An example of his site map is shown in Figure 14.3.
The skeleton plane of Garrett’s scheme is concerned with information design, naviga­
tion design and interface design. A key technique for bringing all these elements together
is the ‘wireframe’. Wireframes aim to capture a skeleton of a general page layout. They are
on the border between information architecture and information design as the various
components of a page are assembled into the standard structures described by wireframes.
To construct a wireframe, designers need to identify the key components of the design
for each different type of page, then place them on a layout. It is very important to consider
not just the type of object - navigation bar, search box, banner headline, advert, text box
and so on - but what content that item can have. It is no use having a very small text box, for
example, if there is a lot of text to go in it. It is no good having a drop-down menu if the user
has to search through hundreds of items. Figure 1 4 .4 (p. 3 1 8 ) shows a typical wireframe.
Visual design is at the top of Garrett’s five elements. Consistency and appropriate­
ness of the presentation are critical here. An effective way of achieving this consistency
is through the use of style sheets. Style sheets describe how Web documents are dis­
played, the colours that are used and other formatting issues that will make for a clear
and logical layout. Just as the wireframe specifies the structure, so the style sheet speci­
fies the visual language used. The World Wide Web Consortium, W3C, has promoted
the use of style sheets on the Web since the Consortium was founded in 1994. W3C is
responsible for developing the CSS (‘cascading style sheets’) language, a mark-up lan­
guage for specifying over 100 different style features, including layouts, colours and
sounds. Different style sheets can be developed for different platforms (so, for example,
the same data can be displayed on a computer or a mobile phone) so that the content
looks sensible on the particular platform it is aimed at. XSL is an alternative language
for specifying the look of XML documents.

Challenge 14.1
Go to th e British A irw a y s flig h t selection w ebsite a t w w w .britishairw /travel/
hom e/public/en_gb. Try to p ro d u ce a w irefra m e fo r this site. G o to a n o th e r airline's site
a n d d o the sam e. C o m p a re them .




edit user

new user





post topic

post new




archive by

I continue to:


new prefs


/ (ic )\

F ig u re 14 .3 Site map design (continued over three pages)
(Source: After site map from Courtesy of Jesse James Garrett)

continue to:

/(le )

C h ap te r 14 • D esigning w eb site s

( la ) If user is logged in, return e d it user prefs. If user is not logged in, return login.
(lb ) If user is logged in, return post new topic. If user is not logged in, return login.
( l c ) Display links to topics posted in the last n days, where n is defined in user
prefs. For users not logged in, n=7.
( l d) Display links to topics matching search criteria.
( l e ) Display links to topics posted in selected month.
( l f) If user is logged in, logout function is available.

/ (ld )\


Part III • Contexts for designing interactive systems

( 2 a ) If login info is valid, return lo g in c o n f ir m e d .

If login info is invalid, return lo g in .

Figure 14.3 Continued

Chapter 14 • Designing websites

c o n t in u e f r o m :










(3a) Functionality for the M etaTalk area is

Figure 14.3 Continued

selector ( I c)
selector ( I d)
selector ( I e)


pop-up window

not documented in this diagram



c o n t in u e f r o m :


on comment


approve comment
revise comment


Part III

Contexts for designing interactive systems

Fig u re 14.4 W irefram e

14.3 The information architecture of websites
Information architecture is concerned with how the content is classified and organized.
Techniques such as affinity diagrams and card sorts (Chapter 7) are used to understand
how people conceptualize content.
The difficulty is that different types of site have to serve many different purposes
for many different people. Getting an information architecture that is robust enough to
serve such multiple interests is difficult and website ‘information architects’ are in great
demand. The features of websites will clearly vary widely.

Implementing websites
Websites are implemented on the Internet by specifying the layout o f the pages in a lan­
guage known as the Hypertext Mark-Up Language (H TM L) w hich is itself a variant of the
Standard Graphical Mark-up Language (SGML). As a mark-up language HTM L suffers from
not having much functionality. Essentially it is a publishing language w hich describes how
things are laid out, but not how they should behave. For this reason the W eb itself suffers
from som e awkward interactions when real interactivity is required (such as submitting
forms to a database). M ore recently, dynam ic H TM L has been developed, which allows
functions m ore com m only associated with a graphical user interface such as a 'drag and
drop' style of interaction. It is also possible to embed interactive displays into an HTM L
page by writing a 'movie' in the programming language Flash. Once again this facilitates
new methods of interaction such as drop-down menus. HTM L5 is now becoming estab­
lished as the standard for structuring and presenting content for the Web.

Information architecture for websites is to do with how the content of the site is
organized and described: how to organize the content (i.e. create a taxonomy), how
to label the items and categories, how to describe the content in the site and how
to present the architecture to users and to other designers. To borrow the title of

Chapter 14 • Designing websites

Christina Wodtke’s book, we are engaged in Information Architecture: Blueprints for
the Web (Wodtke, 2003).

Classification schemes
The choice of an ontology or classification scheme is crucial to how easy it is to retrieve an
instance of an object. The ontology is fundamental as it affects how things can be organ­
ized. Morville and Rosenfeld (2006) distinguish between exact organization schemes
(of which there are three - alphabetical, chronological and geographical) and ambigu­
ous schemes that use subjective categorization. Nathan Shedroff (2001) suggests that
there are seven organizational schemes: alphabets, locations, time, continuums (i.e.
using some rating scale to rank instances), numbers, categories and randomness.
Alphabetical is a very common organizational scheme, of course, and is exploited in all
manner of information artefacts such as phone books, book stores and directories of all
kinds. Although at first sight an alphabetical organization is straightforward, it is not always
easy, especially where forenames and surnames are muddled up, or where rogue charac­
ters can get into the name. Where is a V in the alphabet, or a
Another occasion when
alphabetical organization breaks down is when the formal title of a company or organiza­
tion is not the same as the informal name. Looking in the paper-based phone directory for
the phone number for Edinburgh City Council recently, I finally found it under ‘C’ for ‘City
of Edinburgh’! There was not even an entry under ‘E’ pointing to the entry under ‘City’.

Ontologies, taxonomies and epistemologies
Ontologies have becom e a popular topic of research in recent years because o f issues
o ver the vast am ounts o f inform ation on how best to conceptualize activities associated
w ith this. Philosophically the concept o f an ontology is concerned w ith w hat things
exist, with the nature o f those things that make up our experience. H ow w e choose to
group these together is the concern o f taxonom ies. A taxonom y is a method o f clas­
sification. Both ontology and taxonom y provide philosophers w ith plenty to talk about.
Even things such as plants are not organized into a single agreed taxonomy, but rather
several taxonom ies coexist. Epistem ology concerns how w e com e to know things, with
the nature o f knowledge and o f knowing.

Classification is difficult
These am biguities, redundancies and deficiencies recall those attributed by D r Franz
Kuhn to a certain C h in ese en cyclo p ed ia entitled C e le s t ia l E m p o r iu m o f B e n e v o le n t
K n o w le d g e . On those rem ote pages it is written that anim als are divided into (a) those

that belong to the Emperor, (b) em balm ed ones, (c) those that are trained, (d) suckling
pigs, (e) merm aids, (f) fabulous ones, (g) stray dogs, (h) those that are included in this
classification, (i) those that trem ble as if they w ere mad, (j) innum erable ones, (k) those
drawn w ith a very fine camel's hair brush, (I) others, (m ) those that have ju st broken a
flo w er vase, and (n) those that resem ble flies from a distance.
Source: Jorge Louis Borges (1999), essay: 'The Analytical Language of John Wilkins'

Chronological organization is suitable for historical archives, diaries and calendars, and
event or TV guides (see Figure 14.5).




Part III • Contexts for designing interactive systems

Fig u re 14.5 Yahoo! TV guide

Geographical organization suits travel subjects, social and political issues and
regional organizations such as wine sites, local foods, etc. Problems can arise, of
course, when one’s geography is not good enough. The time zones on my calendar pro­
gram are organized geographically (I think), which makes finding certain time zones
very difficult (see Figure 14.6).
Organization by topic or subject is another popular way to structure information, but here
it is important to prototype the names of topics with the potential users of a site. Often a topic
structure used by people internal to an organization is different from those from outside.
Task organization structures the website by particular activities that people may
want to do (‘Buy ticket’; ‘Contact us’).

Figure 14.6 Time zones feature in MS Entourage, presumably in some geographical sequence

Chapter 14 • Designing websites

Audience is another popular structuring method. This can be very effective when
there are a few well-defined types of user. ‘Information for staff, ‘Information for stu­
dents’, and so on, helps different users find their part of a site.
Hybrid schemes can be (and often are) used to mix these types of organization
together. Other authors suggest that there are other organizational schemes. For exam­
ple, Brinck et al. (2002) include ‘departm ent’ as a scheme. They give the following
example to illustrate the differences:

Task-based: ‘Buy a Car’
Audience: ‘Car Buyers’
Topic-based: ‘Cars’
Department: ‘Sales Department’.

Faceted classification
Any website can be described in terms of three key features: its dimensions, the fac­
ets (or attributes) of those dimensions and the values that these facets can take. The
dimensions come from the ontology - the major concepts in the site. So, the travel site
illustrated in Figure 14.7 has dimensions of cars, flights, hotels and so on that serve
as titles for the tabs along the top. Each of these has certain common facets (such as
price) but also may have its own unique facets: flights go from one city to another,
hotels are located in a single city (but may be part of a chain), cars generally are rented
and returned to the same location but may exceptionally be returned elsewhere. Ferries
have a different pricing structure from planes which have a different structure from
trains. Each of these attributes, or facets, can take certain values. The name of a city, for
example, could be just about anything, but the name of an airport could be restricted to
a known list of official airports. Classification in terms of the facets of dimensions works
particularly well in small, clearly defined spaces. Music sites classify music in terms of its


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Part III • Contexts for designing interactive systems

main facets, such as genre, artist and title. Recipe sites will have facets such as country/
region, main ingredient, course/dish and so on. Wodtke (2003) points out, though, that
once such a site includes things such as cooking utensils, the sharing of facets across
such different entities as utensils and recipes is no longer possible. Faceted classification
has an important impact on the interface that is provided. With clear and known facets
and values the interface can be optimized to exploit the structure.

Challenge 14.2
Consider some classification schemes for a music website.

Organizational structures
One thing that a designer can be quite sure about is that he or she will not be able to
fit everything onto one page. Some decisions will have to be taken about how to break
up the site to accommodate this constraint. There are a number of standard organiza­
tional structures for this. These, of course, tie in with the classification schemes chosen.
A hierarchical structure (also sometimes called a ‘tree’, although it is an upside-down
tree) arranges the pages with a single root at the top and a number of branches under­
neath, each of which has several sub-branches. For example, in a music website, the
root page might be called ‘home’, then branches under that might be ‘Classical’, ‘Rock’,
‘Jazz’ and so on, each of which would be split into sub-genres. Hierarchies are a very
common organization and lead naturally to the technique of providing a ‘you are here’
sign. Figure 14.8 shows a page from a shopping website.

PriceGrabber o._,. y

Your Lists

Your Account

JftU p OJf wUliHJuiy -

Babies & Kids
Consumer Electronics
Health & Beauty
Indoor Living
Jewellery & Watches
Movies (DVD & VHS)
Musical Instruments
Office Products
Outdoor Living
Sporting Goods
Video Games
Wine. Food & Gifts

Figure 14.8

Hierarchical organization of a shopping website

(Source: Courtesy of LLC)

Bookmark This Pag«

Chapter 14 • Designing websites

The impact of ontology
Information architecture is concerned with the structure and organization of objects
in an interactive system. The first thing designers must do, then, is to decide how to
conceptualize the domain; they need to define an ontology. The ontology - the chosen
conceptualization of a domain - is critical and will affect all the other characteristics of
the information space.
Deciding on an ontology for some domain of activity is deciding on the concep­
tual entities, or objects, and relationships that will be used to represent the activity.
Choosing an appropriate level of abstraction for this is vital as it influences the number
of entity types that there are, the number of instances of each type and the complexity
of each object.
A coarse-grained ontology will have only a few types of object, each of which will be
'weakly typed' - i.e. will have a fairly vague description - and hence the objects will be
quite complex and there will be a lot of instances of these types.
Choosing a fine-grained ontology results in a structure which has many strongly
typed simple objects with a relatively few instances of each. In a fine-grained ontology
the object types differ from each other only in some small way; in a coarse-grained
ontology they differ in large ways.
For example, consider the ontology that you (acting as an information architect)
choose to help with the activity of organizing the files in your office. Some people have
a fine-grained structure with many types (such as 'Faculty Research Papers', 'Faculty
Accommodation', 'Faculty Strategy', etc.) whilst others have a coarser structure with
only a few types (such as 'Faculty Papers'). These different structures facilitate or hinder
different activities. The person with the fine-grained ontology will not know where to
put a paper on 'Faculty Research Accommodation', but will have less searching to do to
find 'Minutes of April Research Committee'.
In my office I have a large pile of papers. This makes filing a new paper very easy - I
just put it on the top. But it makes retrieval of specific papers much more time-consum­
ing. My colleague carefully files each paper she receives, so storage takes longer but
retrieval is quicker.
The size of an information space is governed by the number of objects which in
turn is related to the ontology. A fine-grained ontology results in many object types
with fewer instances of each type, and a coarse-grained ontology results in fewer
types but more instances. A larger space will result from a finer-grained ontology, but
the individual objects will be simpler. Hence the architecture should support locat­
ing specific objects through the use of indexes, clustering, categorization, tables of
content and so on. With the smaller space of a coarse-gained ontology the emphasis
is on finding where in the object a particular piece of information resides. A fine­
grained ontology will require moving between objects; a coarser grain requires m ov­
ing within the object.

Rosenfeld and Morville (2002) point out the need to consider the granularity of the
ontology as this leads to the breadth vs depth debate in website design. Often the same
material can be organized as a deep structure - only a few main branches but many
sub-branches - or as a shallow and broad structure with many branches and only a few
sub-branches. As a general rule, six to eight links per category is about right, but the
nature of the content and how it would naturally be divided up by the people who will
be visiting the site must also be considered.
The problem with a hierarchical structure is that no matter what classification
scheme is chosen, some item will not fit nicely into it, and the designer will want to put



Part III • Contexts for designing interactive systems

<- That is, they
develop a clear
'mental model'. See
Chapter 2

it under two or more headings. As soon as this happens, the nice clean structure of a
hierarchy breaks down. Soon the hierarchy becomes a network.
Networks are structures in which the same item may be linked into several different
hierarchies. It is a more natural structure but also a more confusing one for people to under­
stand. Often the visitor to a website navigates down through a hierarchy and so develops a
reasonably clear view of the site structure. However, in a network they may then go back up
another branch or may jump from one part of the site to another. In such cases understand­
ing the overall logic of the site is much more difficult. Organizing pages into a sequence is
ideal for dealing with a straightforward task structure such as buying a product or filling in
a series of questions. The different structures are illustrated in Figure 14.9.

Figure 14.9 Common organizational structures: (a) network, (b) hierarchy, (c) sequence

The importance of classification
This is a portion of an article on Jared Spool's User Interface Engineering website in
which UIE investigated different ways of classifying clothes. UIE is a research company
that investigates usability issues in websites. Their site contains several interesting arti­
cles. Here they describe a study investigating shopping sites with 44 users.
Among the thirteen sites we studied, we found five different department-page
designs. Most listed the departments in a left navigation panel, with the galleries
for that department listed in the center. (Look at Macy's department pages - http:// - by clicking on Women, then Tops.)
However, some got clever. For example, the Gap and Victoria's Secret (http://
w ww , both used a menu-based depart­
ment that wasn't a separate page, but instead used menus at the top of the screen.
Old Navy ( used a combination department and gal­
lery page where sometimes the left nav contains galleries and sometimes it contains
products. (Try clicking on Girls, then Accessories. Compare that to clicking on Girls,
then Skirts & Dresses.)
Lands' End ( used a design that had both product
descriptions and departments. (Click on Women's, then Swimwear to see their
department page design.)

Chapter 14 • Designing websites

Finally, Eddie Bauer ( combined text lists of all the
products in the department with a toggle to see the pictures for a gallery. (Click on
Women, then Sweaters. Click on View Photos to see a specific gallery.)
After realizing that there were five basic types, we got very excited about seeing if
the different types made a difference. While we'd expect differences between individ­
ual sites, it wasn't clear that we'd see if an entire type of design outperformed others.
After watching people shopping on the sites, we compared their behaviors. (As
with many of our e-commerce studies, these users came to our facilities with a list of

products they wanted to buy. We gave them the money to make the purchases and
told them to purchase as much on their list as possible. In this particular study, there
were 44 users who shopped for a total of 687 products.)
Studying the different designs on apparel and home goods sites turned out to be
a good thing. Out of the 687 shopping expeditions that we observed, users only used
the search engine 22% of the time. That means that 78% of the time they used the
categorization scheme to locate their desired products.
We found the sites with the standard left-nav design, such as Macy's, actually per­
formed the worst, selling the least amount of product. Lands' End's design performed
the best, with Old Navy's combination design being second.
It turned out, in our study, that the number of pages that a user visited before they
put something into their cart was inversely proportional to purchasing. The more
pages they visited, the less they bought. (Remember, our users knew exactly what
they wanted and were ready to make a purchase.)

Metadata means data about data and in the case of websites this means data about the
content of the site. Metadata is becoming increasingly important with the ubiquitous
use of tags. Here people develop their own ad hoc taxonomies, often called ‘folksonomies’. We return to discussing this in Chapter 15.
Wodtke (2003) suggests that there are three types of metadata for describing websites:
• Intrinsic metadata describes the factual, technical nature of the data files. It covers
things like file size, resolution of graphics, type of file, etc.
• Administrative metadata is concerned with how the content should be treated. It
might include details of the author, date of origin, dates of any revisions, security
issues and so on.
• Descriptive metadata highlights the facets of the thing, the ways it is classified and so
on, so that it can be found and related to other items of content.
Metadata is easily seen and indeed is used by search engines on the Web to locate
and rank pages for relevance to a search term entered. Figure 14.10 shows how some
metadata is specified in HTML.
For example, an image on a photo library website will have a description below it
showing how the picture is categorized. The website will allow users to refine their
search based on these keywords. I could, for example, request more images of the per­
son shown in the photograph. There is more on metadata and tagging in Chapter 15.
A taxonomy is a classification scheme. There are many different types that serve many
different purposes. One of the most famous is the Dewey Decimal Classification that is



Part III • Contexts for designing interactive systems

Figure 14.10 Example HTML tags

used to classify books in libraries. It is a hierarchical structure that divides books into 10
top-level categories such as:

computers, information and general reference
philosophy and psychology

and so on. Within each classification more levels can be added with decimal points: 005
is computers, 005.7 is information architecture and so on. Of course, all schemes get
out of date and it is perhaps strange that religion gets as much space in the scheme as
computers. In our university library there are several rows of shelves devoted to the 005
classification, but only part of a row devoted to 200.
One of the problems with devising a taxonomy is that different people use different con­
cepts to organize things. Another is that people use different words and terms to refer to the
same thing. There are synonyms and homonyms. There are slight variations of meaning
and often it is difficult to find a home for an instance of something. A thesaurus is a book
of synonyms and semantic relationships between words. Similarly, in information architec­
ture there is often a need to define a thesaurus to help people find what they are looking
for. Rosenfeld and Morville (2002) suggest the structure illustrated in Figure 14.11.
The preferred term is at the centre of the structure. It needs to be chosen carefully so that
it will be recognized and remembered by the people using the site. Far too often these terms
are chosen by administrative staff and reflect an administrative view of things. Our univer­
sity has a heading ‘Facilities Services’ on its website rather than ‘Catering’, and the library is
now a ‘Learning Information Service’. Different nationalities will use different words. The
preferred term should be linked to any number of variant terms. These are synonyms that
people might be expected to use, or follow or type into a search engine. Narrower terms
describe sub-categories of the term (sometimes called siblings) and these are related to
other terms (sometimes called cousins). Moving up the hierarchy takes us to a broader term.
Specifying all these relationships is a lengthy but important activity for the informa­
tion architect. This structure will be used to explain the conceptual structure to people
using the site and to people administering the site. It will be used in displaying the content
on the page, as part of the navigation system and to help people searching. This scheme
also helps to provide functionality such as ‘may we also suggest’ on a shopping site. The
scheme will be used to provide category information for people, navigation bars and the
‘breadcrumbs’ that show where you are on a site. We return to these when discussing navi­
gation. You can see the scheme at work on sites such as Yahoo! (Figure 14.12). Lookatthe
different categories returned when searching for ‘cheese’ on Yahoo!.

Chapter 14 • Designing websites

Broader term

Hierarchical relationship


Variant term

Preferred term


Variant term

Hierarchical relationship

Related term

Narrower term

Related term

Figure 14.11 Structure of thesaurus
(Source: After Rosenfeld and Morville, 2002, p. 187)

' i X H O O f S E A R C H s a , ...


S hopping > C heese
Qitfictag > Business and economy > Showing and Services > Feed end prjrtk > Pa»ry > Cheese
Search 1

I f .11 sR*s

this c«t.gory only

UK only

Inland only

Search |

INSIDE YAHOO:___________________________________________________________________________________________________________________________________________________________________________
•Yahoo! UK 4 Ireland Business Findei- Find local businesses serving your area.
All Listings | S I UK Listings Only 11 1 Ireland Listings Only
a Brand Names (42)
SITE LISTINGS____________________________________________________________________________________________________________________________________
Alphabetical | Bv Popularity
a AJe«Fatm Products 5 - Provides gourmet cheeses and associated products as well as Information on cheese and wine selection
• S B Alham Wood Cheese * • Sells cheese made from Water Buffalo milk.
a Artisan Pantry * - Offers premium quality Imported, domestic and gourmet artisan cheese shipped anywhere In the USA Site also Includes gourmet cheese baskets, cheese wheels,
cheese markers, gilt crates, luxurious serving pieces, and more
a Bedford Cheese Shop * - New York City-based shop offering a wide selection of line artisanal and farmstead cheeses, gourmet foods, and gift baskets
• S B British Cheese Board * - Promotes the wealth of British cheeses available Includes recipes, news, and cheese facts
• Case Coccom * - Offers Italian Parmigiano Reggiano cheese
• S B Cheese SWines co uk* - Supplies farmhouse cheeses, wines, preserves, chocolates, and hampers
• Cheese Board The * - Wisconsin and Imported cheeses, featuring Cheddar, Colby, Muenster, Swiss, and Havarti, as well as an extensive line of gift boxes
• Cheese Box 5 - Fine cheese, wine and gifts from the Dalrytand
• Cheese Express* - Offering imported and domestic cheeses, gift boxes, meats, and other gourmet products
• SG3 Cheese Hamlet The * - independent retailer of swlss cheese In the U K.
• Cheese Store of Beverly Hills * - Unusual European cheeses, gourmet foods, gift baskets, etc
• S B Cheeseboatd of Harrogate The * - Specialises in Yorkshire farm cheeses, but also offers a range of European cheeses
• CheeseMouse com * - Offers Wisconsin cheese and curds
• C heeseviiie Cheesebo»e? * - Offers a variety of farm made cheeses
• S B cheestnnas* - T h e peeiabie stringy cheese Site Includes games for kids
• C hestnut Hill Cheese Shop Online. The * - Order oourmet cheese online
• Consoiao del Formagqio Parmigiano-Regqiano * - official site for the Consortium for Parmaglano-Reggiano Cheese, Includes history and Information about how the cheese Is made,
(in Italian and English).
Cornish Cheese Company. The * - Produces traditional farmhouse cheese Online store available
• <58Cornish Country Larder Ltd * - Manufacturers of speciality Cornish cheeses including Bne and organic smoked cheese, made with goat and organic cow milk
• Cowgirl Creamery* - Working wiffi farmstead and artisan cheese makers, producing cow's, sheep's, and goat's cheeses

Figure 14.12 Searching for 'cheese' on Yahoo!



Part III • Contexts for designing interactive systems

14.4 Navigation design for websites
The design of navigation mechanisms is the second main pillar of information architec­
ture. Brinck et al. (2002) add to the general ideas of navigation by identifying seven types
of navigation (see Box 14.5), from the omniscient user (‘they benefit from short, efficient
paths’) to rote memorization (‘use distinctive landmarks and orientation cues’). Along
with Morville and Rosenfeld (2006) they identify three key features of a good navigation
design for websites: labelling, navigation support and searching mechanisms.

How people navigate
• Omniscience. Users have perfect knowledge and make no mistakes - provide short,
efficient paths.
• Optimal rationality. Users reason perfectly, but only know what they have seen make sure links provide adequate cues to the content they lead to.
• Satisficing. Users avoid remembering and planning and make decisions on what is
immediately perceptible - organize the page to make the most important content
and links available immediately.
• Mental maps. Users actively use the cues available to try to infer the structure of a
website - organize the site simply so that users can easily conceptualize it. Design
the navigation bar and site maps to reinforce this mental map.
• Rote memorization. When users find a path that works, they tend to remember and
repeat it - make sure the most obvious solution is also efficient. Use distinctive land­
marks and orientation cues to help people recognize where they have been before.
• Information foraging. Users try to get as much as possible at one location - enable
spontaneous discovery by providing context, structure and related topics.
• Information costs. Users have limited knowledge and reasoning ability - minimize
the mental costs of sense making, decision making, remembering and planning.
Source: Brinck et al. (2002), pp. 126-7

Labels are used for internal and external links, headings and subheadings, titles and related
areas. Not all labels are text and iconic labels can be very useful if the context and design are
clear. Paying attention to good, consistent, relevant labels is a critical part of information archi­
tecture. Information architects must develop a clear and unambiguous preferred vocabulary.
There is nothing more confusing for people than a website changing its own vocabu­
lary, for example referring to ‘products’ one minute and ‘items’ the next. The same labels
should be used on searching mechanisms as on the main pages, in the names of the
pages and in the link names. Figure 14.13 shows the front page of the ‘Web Pages That
Suck’ site. This is a great site full of bad designs. However, I found it quite difficult to
find what was on the site, because the labelling is not very clear.
Navigation support
Of course, many of the signs and labels on a website are deliberately placed in order
to support navigation. It is common to have a navigation bar across the top of a site
that points to the main, top-level categories. This is often called the global navigation
bar. Within each of these there will be sub-categories. These might be placed down the
left-hand side of the site or may drop down when the main category is selected. These

Chapter 14 • Designing websites

I started this site back in Ju ly 1996 so I wouldn't have to teach a d
Since I'm one of those extremely clever marketing folks, I chose a nan
marketing appeal and was edgy. I could have more accurately called tl
Pages That Have Problems" but nobody would remember and it's bor

The purpose of this web site is to help people design effective and aes
pleasing web pages. My methodology is somewhat different. I believe
is exposed to bad web page design they'll be less likely to use these tec
pages they create.

F ig u r e 14.13

The Web Pages That Suck site


are known as local navigation. It is a good design principle to have the global, top-level
navigation bar the same on every page so that people can easily jump back to the home
page, to a ‘frequently asked questions’ page or to one of the other main categories.
An essential feature of the navigation features of any website is to provide a “you are here’
sign. This is often presented by a description showing where people are in the hierarchy of
the site. Other devices such as indexes and glossaries are helpful in assisting people find
exaedy what they are searching for. A site map should be made available that can be called up
when needed. The map displays the structure and content headers of the various categories.
Figure 14.14 shows a university website where several different types of navigation are used.


... □

Edinburgh Napien

*A-Zpf gll KM-reS


►Loam @ Napier

* Live @ Napier


►Faculties & Schools

►Research a Knowledge Transfer

►Business Acsvrsos

* Alumni

>About U s

Research students
Research degrees

R e s e a rc h

Research centres

The School of Computing has an active research community pursuing research in applied computing. We are committed
to the creation and maintenance of a culture of research underpinned by scholarship and this applied research activity
feeds back into our taught courses

SoC home

in the most recent Research Assessm ent Exercise IR A E ) our research was w as rated a s Being of 'international-standard'
with Library and Information Management awarded a 4 rating and Computer Science scoring a 3a rating
We have five research centres which all sit under the Centre for Informatics Research (C IR ) which w as established in
2006 to provide the administrative and financial support and facilities to sustain all research and knowledge transfer m
computer science and informatics Take a look at research areas currently active within these centres
In addition the School undertakes University wide research with the Transport Research Institute and the International
Teledemocracv Centre Research grant income currently averages around £600,000 a year coming from both the U K and
Europe In addition the Schoo operates around eight Knowledge Transfer Partnerships permitting transfer of research
technology into local companies

Edinburgh Napier University, Cratglockhart Cam pus. Edinburgh, EH14 1DJ
Telephono 08452 60 60 40

Send US a n Enquiry

F ig u r e 14.14

homo I FOt | PnvocypoScy | CopyngN j Skomop I 8kjdeNovels page much as shown in Figure 14.20.
This design showed off the visual images of the book covers well and worked fine for
parts of the site where there was only a small amount of content (such as Short stories,
and Poetry). For Novels, however, it resulted in a very long page as there are 13 nov­
els to accommodate. WD tried various designs to try to fit all the novels on one page.
Unfortunately, these made the visual images of the book covers look quite unimpres­
sive. He tried larger images and other layouts, all of which were discussed by the team
over e-mail. Finally he finished up with the compromise shown in Figure 14.21. There
is enough showing for people to realize that they will have to scroll, the images are
large enough to make an impression and the layout is aesthetic for the 13 items that
need to be accommodated.
By the end of March there had been significant progress:
• The team had named the site the RLS Website.
• WD had created a logo for the site, so that it could be easily identifiable and have a
presence both on and off the site.
• WD had created a banner for the site - we would also make a printed copy to bring to
any presentations, conferences etc.
• The team had decided on a colour scheme - largely Victorian muted colours (dull
reds, sepias) but also some blues and purples.
• The team had decided that each section would have a quotation from RLS which
related to the content of that section.
• WD had worked on the navigation aspects of the site and had begun to upload images
so that the site was now beginning to take shape.


i . L i i
Short Stores

R L S W orks


Other Wring
Coaecteo Edteors
PuOfcahors Chrcnotogy

P a T C T iB

manias, fit)at aty earliest childhood, it was mine
able to ’unite, i became a good fitend to the paper maker1'

make a plaything o f imaginary senes o f events.

Rooen Loue Stevenoor e rot only remarcaoto lor the numoet of worst he oroOucod r he twenCy year Herary earoer out also lor Ste range of
genres he aooolsq essays, travel wafting, short stories, novels and romances, as wol as poetry, plays and Ptograohy. Wthjr. these genres, loo.
he output e rorrarvaoto lor what Henry James cate he Constan varety of e»pot men
The Worst pages are owvotoc to al of the worse RLS oroauceo. You can Drowse the worse oy genre, r the eft-hero mere, or chronobgcaly r
the menu petow Once you ctcs or e wots, you wi fino a Prof synopsis. a let of ocSons of that wots and also a Dtetogrschy of crBcal wrung*
aoout the wots You w»ateo»rc tul tests of the worst Doth in POF format and as fkhoooss Frety. the Puotcaoors Chrerotogy • a complete
Istsxj. nctxsmg ouotcator delate, of Stevenson's works
Short List o f W orks by Decade - for a complete list see Publications Chronology
18 70 s

An intend Vo,age (18T8)

• C dr&jrgh Pctjrcsquc .Notes i 18TB)
• Travels n th a Donkey r\ the Co-ernes (1879)


Vrgsiteus Pucragoe andOfhrv Pacers f t 881 *

• ra n te r- Studies o f Mon and Books {188? i
• .M e* A rab*tn N gfas 11888)

Treasure fstesdl 1883)


The S**erode Squatters 11884)


The Bpoy Sralch c r'(1884)


4 Chad’s Gordon o f Verses 1188V

• More New A/obetn Ngftfs The Dynamiter (w4h Faney. 1085)
. Pence O ta i t 885)
• Strange Case & O i Jo tytan d M -M ydel 1886)
• Kdhaoood)1088)

Figure 14.20 RLS original layouts model



Part III • Contexts for designing interactive systems

The team established the first level of sections as follows:


In the Footsteps of RLS

Figure 14.20 illustrates the results of the colour discussion and the banner. RA had spent
considerable time working through various photos to select one for the banner that gave the
right feeling. Since RLS had written several books associated with the sea, the sailor image
at the centre made a key point. The images of RLS used either side captured the young and
more mature Stevenson, looking inwards towards the site. The colour scheme worked nicely
and would be followed through throughout the site. The RLS website logo can also be seen.
Notice in Figure 14.21 how the titles of the level-one categories have changed since
the original list above. In prototyping the design and working through the various infor­
mal scenarios suggested by the personas, we had realized that titles such as Resources
and Community were too general.

Figure 14.21 Novels' front pages

RA and PL undertook some informal card sorting to ensure that the second-level
material did fit clearly into one of the top-level categories. DB had argued for a ‘threeclick’ design where possible, so that visitors to the site could get where they were going
in three clicks. This made some sections quite difficult to design. In Figure 14.22 we
can see the ‘In the footsteps of RLS’ section that directs people to places Stevenson had
a particular affinity with. WD came up with the double-column design to ensure all the
locations could fit on one page. Figure 14.22 also illustrates the use of the quotations
that were included on each level-one front page.
During this time RA had been very busy making contacts and finding material for the
site. She managed to source a complete set of full-text editions of the RLS novels with
an agreement that the RLS website could access them. She had uncovered several hun­
dred previously unseen photos of Stevenson from an archive in the Writer’s Museum in
Edinburgh and had obtained the following agreements alongside many others.
• Contacted Edinburgh University’s special collections about the possibility of digitiz­
ing images of Stevenson’s records of attendance.
• Received permission to use the Bournemouth/Swearingen images of Stevenson from
the Beinecke Library at Yale University.

Chapter 14

Figure 14.22 In the footsteps of RLS

• Received permission from the University of South Carolina to use the images from
their Stevenson exhibit (mostly images of early editions of Stevenson’s works).
• Received images of the exterior and interior of the Silverado Museum.
• Received images of the exterior of the Stevenson State Historical Monument, Monterey.
• Received images of the exterior of the cottage at Saranac Lake.

Evaluating websites
Once a website is up and running there are many ways to evaluate it. Information
provided by software such as Google Analytics can help designers monitor who has
accessed the site and when and how long they spent on the site. Measuring the number
of clicks taken to arrive at a certain place in the website is another good indication of
usability. The click distance is a measure of navigational difficulty.
Many companies such as Google and Microsoft use the A-B method of testing. In
this approach a new page design is made available and users are randomly assigned
to the old version (A) or the new version (B). Measures of click distance, time taken to
complete a task and user surveys such as a simple click star rating can be used to com­
pare the two designs. However, attention should be paid to setting up a well-controlled
experiment with no confounding variables, as described in Chapter 10.

During April the main aim was to populate the site and write the content for the site. A
colleague in Canada with experience of writing content for the Web was able to provide
valuable advice on how to write for the Web. It was also important to plan the site’s
launch. In June the site was ready for evaluation and Stevenson scholars worldwide
were invited to critique the design and content.
An on-line survey was developed and hosted on Survey Monkey. It was based on the
design guidelines developed in Chapter 3 and applied to the particular issues of the RLS
website. (The questions are shown in Figure 14.23. Compare these with the guidelines
from Chapter 3.) The RA developed a sample scenario for each of the personas and mailed
this to members of the RLS community. They were invited to explore the site, look at the site
from the perspective of different personas and to mail the RA with any general comments.
Overall the general impression of the site was good. Inevitably people had their own prej­
udices about what was important. This was one reason we had developed so many different

Designing websites


Part III • Contexts for designing interactive systems

personas: so we as the design team could keep in mind how many different types of people
would access the site, and not get bogged down in the needs of one or two specific groups.
The power of the personas was well demonstrated by one respondent who commented that
she had difficulty finding the information required when working through scenario 7, but
found it easily when working through scenario 8. This showed how important the way that
people framed their information needs was in making use of the navigational structure.
Another comment concerned making the content more ‘Web-friendly’; ‘i.e. shorter,
tighter, chunkier and keyword-emphasized’. The same respondent suggested looking at
the design of the horizontal bar across the pages as, viewing it on his 15-inch screen, the
bar was top heavy. It forced him into a lot of unnecessary scrolling.
The results of the survey are shown in Figure 14.23. Of course, it is always difficult
to interpret such data as some people will tend to put ‘agree’ when others would put
‘strongly agree’, and so with only 18 responses it is difficult to tease apart too much
detail. However, it is clear that there is strong support for the first four questions. The
following five are less clear-cut and the question concerning control has produced over
50 per cent who can only ‘agree’ rather than ‘strongly agree’. The negative question, ‘I
felt rather lost when using the site’, brought a positive result and helped to ensure that
people were paying attention when filling in the questionnaire!

Challenge 14.3
Go through the results of the questionnaire and write your interpretation of what you can
say as a result of this survey. What would you focus on when making changes?

A number of key changes were made following this evaluation. The team agreed to
work on, and adopt, a particular house style for writing content, much as we had agreed
on a colour scheme and overall ‘personality for the site. The team agreed to prioritize
the remaining work to ensure that all the site visitors would be accommodated. RA

Chapter 14 • Designing websites

would develop the sections on Life, In the Footsteps and the plot synopses in the house
style that had been agreed. WD would concentrate on getting the gallery fully func­
tional and getting all the pictures tagged with event, location, person, relationships and
year. Three hundred images had to be uploaded, tagged and made ready for the site. RA
would also pay attention to the Community part of the site to ensure that people could
comment, rectify any errors and participate in the wider RLS community.
The site officially went live on 13 November, the anniversary of Stevenson’s birth.

Summary and key points
In this chapter we have looked at the design of websites. As with the design of all interac­
tive systems, the design of websites requires understanding, envisionment, design and
evaluation and a clear view of the purpose of the system.
• Website design needs to follow sound design principles and will include the develop­
ment of personas, scenarios and a clear design language.
• Information architecture is concerned with understanding the structure and organi­
zation of the content of the site.
• Navigation concerns how people move around the site and how they get to know
what is on the site and where it is.
• The case study illustrates many aspects of website design, but also shows how much
else goes on around the design of a website.

E x e rc is e s
1 There is no better way to get good at Web design than by critiquing other
sites. Go to a website - your university site, say, or your favourite shop, or an
airline. Undertake a structured critique of the site, focusing on the organization
scheme used, the navigation bars and the overall look of the site. Develop
some personas of typical site visitors and work through some scenarios that
they might want to undertake. How easy and effective is the site?
2 Go to the Webby awards website at and look at
which sites win. Think about the different categories of sites and the different
requirements they have.


Further reading

Garrett, J.J. (2003) The Elements of User Experience. New Riders, Indianapolis, IN. A very
approachable little book that packs a lot of good advice into a small package. It does not go into
information architecture in any great detail, but covers the basics of Web design very well.
Wodtke, C. (2003) Information Architecture: Blueprints for the Web. New Riders, Indianapolis,
IN. A highly readable and practical account of information architecture for the Web. A second
edition by C. Wodtke, A. Govella (2009) is now available.

Getting ahead
For information architecture chat and articles:



Part III • Contexts for designing interactive systems

Brinck, T., Gergle, D. and Wood, S.D. (2002) Designing Websites that Work: Usability for the
Web. Morgan Kaufmann, San Francisco, CA. An excellent book on Web design in general.
Rosenfeld, L. and Morville, P. (2002) Information Architecture for the World Wide Web.
O'Reilly, Sebastopol, CA. A more comprehensive book than Wodtke's but it is less accessible
for a general reader. It covers much more ground in terms of thesauri, but sometimes the detail
obscures the message. A later edition by Morville, P. and Rosenfeld, L. (2006) is now available.

Web links
An excellent site for all things about web design is
Also see and


Comments on challenges
Challenge 14.1
Figure 14.24 shows our version of the BA site.

G l o b a l n a v ig a t io n b a r

W e lc o m e b a n n e r

L o g in


Site highlights

Figure 14.24 BA site

Challenge 14.2
Different genres of music often classify things in different ways. So one way of classifying music is by
genre (rock, classical, indie, etc.). Artist is another common category. There could be 'festivals', live
shows' and other categories such as male, girl bands, acoustic and so on.

C h a p t e r 15
Social m edia



15.1 Introduction 342

In th e tw e n ty - firs t c e n tu ry th e re has b e en an e x p lo s io n in th e u se o f

15.2 Background ideas 345

te c h n o lo g ie s to c o n n e c t p e o p le w ith o n e a n o th e r. S o c ia l n e tw o rk in g

15.3 Social networking 351

w e b s ite s su c h as F a c e b o o k a n d G o o g le + a re u se d b y m illio n s o f

15.4 Sharing with others 355

p e o p le e v e ry d a y to e x c h a n g e p h o to s, p la y g a m e s a n d k ee p up

15.5 The developing web 359

w ith th e ir frie n d s ' a c tiv itie s . O th e r site s s u c h as e B a y o r T rip A d v is o r

Summary and key points 361
Further reading 361
Web links 361
Comments on challenges 361

ag g re g a te th e c o m m e n ts a n d re c o m m e n d a t io n s o f o th e r p e o p le to
g iv e h o te ls, re so rts o r e B a y tra d e rs a q u a lity ra n k in g . S y ste m s d e sig n e d
to s u p p o rt th e s e a n d re la te d a c tiv itie s a re k n o w n as so c ia l c o m p u tin g ,
o r so c ia l m e d ia .
In th is c h a p te r w e lo o k at th e rise o f so cia l m e d ia an d a t m a n y o f th e
d esig n fe a tu re s th a t a re u n iq u e to su ch syste m s. S o c ia l m e d ia is an
in te re s tin g p h e n o m e n o n as m a n y sy ste m s th a t sta rte d life as p u re ly
so cia l b e c o m e in c re a s in g ly im p o rta n t to b u sin e sse s. W h e re o n c e a
syste m su ch as T w itte r, fo r e x a m p le , w a s m o stly a b o u t in d iv id u a ls
c h a ttin g a b o u t triv ia , n o w it is used by e m e rg e n c y s e rv ic e s an d
c o m m e rc ia l o rg a n iz a tio n s as an im p o rta n t p a rt o f th e ir o v e ra ll b u sin ess
strate g y.
A fte r s tu d y in g th is c h a p te r y o u sh o u ld b e a b le to :

U n d e rs ta n d th e h is to ry o f so cia l m e d ia
U n d e rs ta n d th e b a c k g ro u n d to th e m a in ty p e s o f sy ste m th a t
c o n s titu te so cia l m e d ia


U n d e rs ta n d th e fu tu re d e v e lo p m e n ts o f th e W e b .

Part III • Contexts for designing interactive systems

15.1 Introduction

L____________________________________________________________________________________________________________________ 4



The World Wide Web, as we know it, began in 1989 when Tim Berners Lee developed the
idea for a hypertext document management system to be used at the nuclear research
centre, CERN, Switzerland. He coined the term ‘World Wide Web’ in 1990 when devel­
oping the first browser based on the Next computer and operating system (Figure 15.1).

Figure 15.1 The first Web browser

Hypertext is the concept of being able to jump from one piece of text to another
through a link embedded in the text. Hypermedia extends the idea to any media. The
concept is so familiar through Web links that it seems strange to imagine a world where
it did not exist, but of course if was only through the introduction of electronically
stored text that automatic links could be automatically enabled. Prior to that, the best
one could hope for was the adventure game books you have as children where making
a particular decision makes the reader jump to a particular part of the book.
The idea of hypertext is usually traced back to a paper by Vannevar Bush in 1945,
but the idea was really popularized by Ted Nelson in the 1960s and through his book
Literary Machines (1982). The first hypertext conferences began in the 1980s and in the
mid-1980s Apple issued their hypertext system, HyperCard, as standard on all Apple
Macintosh computers. Presumably this is why Tim Berners Lee wanted a hypertext doc­
ument management system, and it led to the Web.

Chapter 15

In 1993 a cross-platform browser called Mosaic was developed at the National Center
for Supercomputing Applications (NCSA) - perhaps the most significant piece of inter­
face design ever undertaken. It revolutionized the world. Prior to 1993 there was plenty
of traffic across the Internet, but it was all based on command languages with com­
plex syntax that made using the Internet suitable only for specialists. The advent of the
graphical Web browser suddenly made the locating, downloading, viewing of media
across the Internet available to everyone. The Web spread rapidly, with millions of
people joining every year and with an explosion of websites of shopping, travel, sport,
indeed everything. By the later 1990s companies were trading on the stock market at
vastly inflated prices. Everyone thought the Web was going to make them millions, but
no one could quite work out how to do it. Internet time and Internet logic replaced real­
ity and common sense. In 2001 the market for the Web crashed. The ‘dot-com’ bubble,
as it was known, had burst. But far from this being the end of the Web, it turned out to
be the beginning.
The problem with the original Web was that it was primarily a publishing medium.
The language used for writing websites was based on a mark-up language that
described how to display things and how to move from one place to another. When
Berners Lee introduced the Hypertext Mark-up Language or HTML, he used a very
much simplified version of the publishers’ Standard Graphic Mark-up Language,
SGML (1986). HTML, in the period 1994-8, was in a constant state of flux, as com­
peting browsers Netscape (Mozilla - ‘Mosaic Killer’) and Internet Explorer (based on
Mosaic) ran ahead of the attempts to standardize HTML, adding new visual and inter­
active features, some of which turned out to be dead ends. HTML was particularly
unsuited to updating things in real time and HTML and its component technologies,
such as the scripting language JavaScript, blurred the distinction between content
and how it was displayed.
In the second half of the 1990s many efforts were being made to deal with these
restrictions of the Web. By 1998 XML had been developed as a way of separating form
and content. XML (extensible mark-up language) simply describes the structure of the
contained data, not how it should be displayed. XML describes content by enclosing
the content in between a start-tag and an end-tag. For example  Designing
Interactive Systems describes the title of something as ‘Designing Interactive
Systems’. A specification of how a title should be displayed (e.g. in bold typeface) can
then display this as defined. More structure can be added by using multiple attributes
of an object. For example,  Author= ‘David Benyon’. These struc­
tures required different terms for different areas - for example, the attribute ‘element’
in Chemistry refers to Oxygen or Carbon, whereas in Physics it refers to an electrical
source of heat. Thus different XML ontologies were defined for different areas, such
as Extensible Business Reporting Language (XBRL) or Weather Markup Language
This theme of separating style from content gathered pace during the first years of
the new century, and a range of technologies vied to present and interact with XML data.
Macromedia (now Adobe) Flash was used to render XML content in a visually attractive
way. The programming language Java began to be used to provide more interactivity
in websites and the combination of these two became known as AJAX. The continual
spread of people using the Web meant that the social side of things became as important
as information exchange had been in the early years.
By 2004 it was clear that enough had changed for a new phenomenon to be chris­
tened. The first Web 2.0 conference, or summit, was held in 2004, hosted by the
O’Reilly organization. Tim O’Reilly explains his rationale for distinguishing Web 2.0

Social media



Part III • Contexts for designing interactive systems

from the Web’s previous incarnation. He sees Web 2.0 as a move to much more open
services, with application program interfaces (APIs) that allow others to make use
of services. Software is no longer a huge application running on your computer, it
is a service to be accessed when needed. Web 2.0 is about participation more than
publishing; ordinary people, often unpaid, supply the content and the trail of their
activities adds value. New business models have evolved through Web 2.0 and con­
tinue to do so.

The long tail
In his book The Long Tail: Why the Future of Business Is Selling Less of More (2008),
Chris Anderson discusses new business models where people sell lots of relatively
specialist items required by only a few consumers, rather than selling large numbers
of more standardized items. The Internet facilitates businesses that can exploit the
long tail. For example, Amazon may sell only a few copies of obscure books, but it
is still worth their while to stock them. Other models for businesses include things
such as selling rare music albums or personalizing data to the needs of relatively
few people.

Thousands of small focused applications, Web apps, such as shopping carts, calen­
dars and subscription services, are freely available to be mixed by enthusiastic con­
sumers. Thus the content of websites can be much more dynamic and much more
The result of all this is a fundamental change to Internet computing. Software
engineering processes have changed to be much more agile, with a rapid turna­
round of upgrades and new versions of software. Web 2.0 turned the Web into a
platform for collective intelligence that crosses devices. Since 2004 the term ‘social
media’ has gradually replaced the term Web 2.0 although the web2 summits (www. did still take place until 2011 and were attended by
some very influential people in the field. The future of these conferences remains
to be seen.
In 2006 Jeff Howe coined the term ‘crowdsourcing’ to describe the way the
Internet can be harnessed to create a large crowd of people dedicated to solving
some problem. Wikipedia (Figure 15.2) is one of the most successful examples of
people working together as both providers and consumers (sometimes called ‘pro­
sumers’) of content. Digital photos are another example, with literally millions of
photos covering all subjects being made freely available. Other notable examples of
this active participation of people to tackle problems or work together on significant
issues include surveys, such as surveys of garden birds and the search for extra­
terrestrial life.

Challenge 15.1
What do you think the most important characteristic of a site that allows you to provide
and consume information is?


Chapter 15 • Social media

15.2 Background ideas
Of course, social media did not just pop into existence, and there had been several
commercial examples of social media applications and related research projects dur­
ing the 1990s. The whole area of Computer Supported Cooperative Working (CSCW,
Chapter 16) concerns cooperation, communication and awareness of others. Our own
work during this time went under the name of ‘personal and social navigation of infor­
mation space’. In the introduction to their book, Hook et al. (2003) illustrated the ideas
of what they called ‘social navigation’ with an example of a grocery store:
Consider the design of an on-line grocery store from the perspective of social navigation.
First of all, we would assume that other people would 'be around' in the store. Instead
of imagining a 'dead' information space, we now see before us a lively space where (in
some way) the user can see other shoppers moving about, can consult or instruct special­
ist agents and 'talk to' the personnel of the grocery store. These are examples of direct
social navigation. We also see the possibility of providing information pointing to what
groceries one might buy based on what other people have bought, e.g. if we want to help
allergic users to find groceries and recipes that work for them, we could use the ideas
of recommender systems; pointing people to products that, based on the preferences of
other people, the system believes would be suitable. Sometimes we just like to peek into
another's basket, or just take the most popular brand of some product. These are examples
of indirect social navigation.
(Hook et al., 2003, pp. 5-6)

Social navigation was seen as encompassing a whole collection of techniques and
designs that make people aware of others, and of what others had done. Social net­
working communities, such as those on Facebook, MySpace or Ortuk, exist primarily
for the purpose of enabling people to maintain and build links with other people. Other
systems are more concerned with making people aware of what others are doing, and
yet more, with making aggregate knowledge of others available.

Part III • Contexts for designing interactive systems

A central theme of the early work was to move away from the ‘dead space’ of
information to bring personal and social issues to the fore. The early Web was char­
acterized by vast am ounts of inform ation being rapidly made available. It was,
therefore, difficult to find out what was there and what you were interested in. We
observed that when we talk to someone else, the information we get back is often
personalized to our needs, and the adviser may offer information that changes what
we want to do or how we might approach it, making us aware of other possibilities.
For example, if you need directions to a part of an unfamiliar city you could use a
map, or use a satellite navigation system, or you could ask someone. When you ask
someone you will often get stories, additional information about nice places to visit,
alternative routes and so on. People may ask for clarification, elaborate details and
so on. This personalizing of information comes from the social element of informa­
tion gathering.
People can judge to what extent the information given can be trusted, depending
upon the credibility of the information provider. Even if the information cannot be
trusted, it may still be of value as people know where it has come from. In information
spaces, using person-to-person communication is an important part of the informa­
tion architecture that is often overlooked.
A number of experimental systems were developed during the late 1990s that
explored some of these ideas. GeoNotes (Persson et ah, 2003) is a system for augment­
ing the geographical world with virtual ‘Post-it’ notes. Thanks to the advances in GPS,
an electronic message can be left associated with a particular place. When another per­
son (suitably technologically equipped) arrives at the place, the system alerts him or her
to the message. As Persson et al. point out, such attachments of information spaces to
geographical spaces go back to cave paintings and people continue to annotate places
with graffiti, Post-its and fridge magnets. GeoNotes offers a technologically enhanced
version, putting people in contact with other people (Figure 15.3). In 2008 an iPhone
app appeared that performed a very similar function.



I sellings j about me f friends j debug


- o v e t v i e w ------------- r- I i s t --------------- -------------

g e o n o te s n o t v isib le
g e o n o te s fro m a n y o n e
g e o n o te s fro m frie n d s

per: C o o l club!
a n n a s: F a n ta s tic p izz a !
a n n a : C h eck o u t sw e a te r!
H a n n a : R e m e m b e r sw eat*
b o rje: D o n t e a t h e re !
w a ite r: E x p e n s iv e drinks!
a n o n y m o u s : th is p la c e s sti
A n n a : CD :s c h e a p e r on R<
O la : Y o u m u st g o to th is c
k a lle : w a rn in g : D o n t go he



Figure 15.3 GeoNotes
htm, Fig 2.)

Chapter 15 • Social media

If other people are not around to provide help and advice then there are a number of
systems that try to filter out uninteresting information and point people to things that
they will find relevant (see, e.g., Konstan and Riedl, 2003). Just as a newspaper editor
filters news into a form that readers of that newspaper like, so filtering systems aim to
tailor information to people. (Conversely, we select a newspaper or TV channel because
we like the way that channel filters and presents the news.)
In content-based filtering the information is scanned for specific articles that match
some criteria. Based on a statistical analysis the system rates the relevance of the infor­
mation for the consumer. Usually keyword-matching techniques are used to filter the
information. People supply a preference file to the system with keywords that the sys­
tem should look for in documents. For example, an agent scans a newsgroup for docu­
ments that contain the keywords on a regular basis. This is the basis of systems such as
MyYahoo! (Figure 15.4).

Figure 15.4 MyYahoo!

Challenge 15.2
Join eBay and browse the site. Decide on something to buy and follow the links on sellers
and buyers. What can you learn about people? How reliable do you think the evidence
is? Do you think the information provided on buyers and sellers helps you make a
decision on what to buy and who to buy it from? How does all this contribute to trust?

Recommender systems make suggestions to people for information based on what other
people with similar tastes like or dislike. People using the system are connected to a
server that keeps track of what everyone does - the articles they read, the Web pages
and blogs that they visit, the videos that they watch and so on - in a personal profile.
Personal profiles are matched and the system creates clusters of people with similar

Part III • Contexts for designing interactive systems

tastes. One of the earliest examples of this was Movielens (Figure 15.5). Amazon, the
on-line book and media vendor, is probably the best example of a mature recommender
system. People who subscribe to Amazon can have the system recommend books based
on those that they have bought previously and on those that they rank (Figure 15.6).

1 < ►] <5 • d i | + |v j[h n p //mowHtnt.uiTMvdu/imm

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Figure 15.5 Rating
preferences with
M ovielens
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Another method of providing socially based information is to provide a tag so that
whenever someone comes upon a new piece of information he or she can see what
other people with similar interests think of that particular piece of information. This is
sometimes called social searching. People can tag the items discovered by others, thus
providing a social tagging system, and tags can also be added automatically according
to some criteria. Some sort of rating of the information pieces has to be done by other
people using the system so that the system can create and cluster personal profiles.
The more people who rate items, the more accurately the system can group others.
Ratings can be done explicitly and/or implicitly; implicit ratings are, for example,
time spent reading an article; explicit ratings let people score information sources.

Chapter 15 • Social media

Filtering needs some sort of input to work with, and explicit rating of information
is not all that simple. How do we judge ratings from someone who has created the
information? Explicitly rating information is also an additional burden on people, so
sometimes they will not bother.
An excellent and fascinating example of this sort of rating system is eBay
(Figure 15.7), the on-line auction site. Here, buyers and sellers have ratings based on
the quality of service that they have provided. Buyers rate sellers and sellers rate buyers.
Moreover, you can see what both buyers and sellers have been trading. This allows you
to build up a picture of the sort of person you are trading with.

Figure 15.7 Ebay

History-enriched environments, or ‘readware’, is another technique. What other
people have done in the past can tell us something about how to navigate the informa­
tion space. If we get lost in the woods and come upon a trail, a good idea is to follow
that trail. Similarly, people take certain paths through information space. By making
the activities of others explicit, new visitors to the space can see familiar paths through
it. A very familiar technique is to automatically change the colours on the links in a
Web page when a person has visited that page, so subtly letting them know where they
have already been. In some other systems this may be generalized based on usage of
links. Perhaps the main example of this was the Footprints project (Wexelblat, 2003),
where ideas of interaction history are associated with an object.
Social translucence was a project based at IBM. It employed three core principles visibility, awareness and accountability - implemented in a number of prototype sys­
tems, so-called ‘social proxies’. Erickson and Kellogg (2003) illustrate their concept by
telling the tale of a wooden door that opened outwards in their office. If opened too
quickly the door would smash into anyone who was walking down the corridor. The



Part III • Contexts for designing interactive systems

design solution to this problem was to put a glass panel in the door. This enabled the
three principles of social translucence:
• Visibility. People outside were now visible to those inside who were going to open the
door. Of course, the transparency of the window meant that people inside the office
were also visible!
• Awareness. Now people could see what others were doing and could take appropriate
action - opening the door carefully, perhaps.
• Accountability. This is an important principle. Not only are people aware of others
but now they are aware that they are aware of others. If the person inside the office
opens the door and smashes into someone in the corridor, the person in the corridor
knows that the office person knew this. Hence he or she has to be socially account­
able for the action.
The best known of their prototypes was Babble - a social proxy for meetings, chat
and e-mail. People are represented by ‘marbles’ and the space of discussion by the
large circle in the centre of the system (see Figure 15.8). The more active people
are, the nearer the centre they are, and the marbles gradually move towards the
periphery if they do not participate in the chat for some length of time. Other details
of the people can be seen in the panes around the edge of the system. This is just
one example of a number of visualizations of behaviours that provide awareness of

Figure 15.8 Babble
(Source: Erickson et al. (1999)
pp. 72-9, Fig. 3. © 1999 ACM, Inc.
Reprinted by permission)

Since then, research groups have changed and moved on, and the commercial world
has taken over much of the work of these prototype systems. There are now thousands
of Web apps providing all manner of social media functionality. For example, MovieLens
now has a Facebook app. There are directories of social media applications and awards
for the best ones. For example, has listings as illustrated in Figure 15.9. This
uses a visualization, popular in social media apps, known as a tag cloud. The larger the
typeface the more items there are with that tag.

Chapter 15

0 Listio

Social media


Figure 15.9 Listio website,

15.3 Social networking
There are hundreds of different forms of social networking and almost certainly you
make use of one of them. Facebook, MySpace and Bebo are popular. Although they are
different in style and popularity in different countries, they all provide a mix of updates
and functions such as photo sharing.
Figure 15.10 shows the Orkut log-in page. Once a person is logged into their account
they can join groups, view messages, play games and share media with their friends.
Many social networking sites allow people to make short announcements about their
status, what they are doing, or what they are thinking.
Status updates is the whole purpose of Twitter. This application lets people post short
messages concerning what they are doing. Twitterers are able to follow the messages
(‘tweets’) of other twitterers. Many of these are simply messages such as ‘having cof­
fee in Oxford’ or ‘lost in Boston’, but many other uses have been found for it. Terrorist
attacks have become news first on Twitter, as have plane disasters and other events.
Businesses use Twitter to promote their interests. Of course, there are millions of people
using Twitter and a plethora of Twitter help sites have grown up. For example, tweettag
(Figure 15.11) allows people to see the most popular tags.
There are also a number of professional social networking sites such as Linkedln,
Pulse and Namyz. These allow people to present their profile for their professional life.
Increasingly these sites add new applications. For example, Linkedln allows for shar­
ing PowerPoint files and has common interest groups, with regular updates. Twine is
another popular example. Figure 15.12 shows Linkedln.

0 ^ 0


Part III • Contexts for designing interactive systems

(Source: www.orkutcom/Main#AppDirectory.aspx; Orkut™ is a trademark of Google Inc.)

The style and look and feel of the sites reflects the different markets and custom­
ers that are the focus of these sites. There are also companies that provide software
that allows people to add social networking to their own sites. This allows topic-specific
social networks. For example, provides a bundle of ‘social media’
tools that allow programmers to create member profiles, news feeds, ratings and
reviews. People can add their own content and edit that of others (Figure 15.13).

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FO R l A l.
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Chapter 15

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Part III • Contexts for designing interactive systems

The Obama campaign
In 2008 Barack Obama was elected president of the United States of America. During his
campaign he and his team made extensive use of social media technologies, with on-line
presence on MySpace and Facebook and regular updates on Twitter. He employed Chris
Hughes, one of the founders of Facebook, to develop his on-line campaign. He had his
own on-line community at, with over 1 million members. During
the period August to November 2008 there were 500 million blog entries that men­
tioned Obama (in contrast to 150 million for his opponent, John McCain). Obama had
844,927 'friends' on MySpace and 118,107 followers on Twitter. Following his election
the use of social media technologies continues through the website.

There are now thousands of community websites and social networking environments.
Some of these revolve around travel, such as TripAdvisor, others focus on activities such
as hiking or cycling, or knitting ( Others focus on finding the best pizza in
a town, the best bars and restaurants, or the best bookshops.
Indeed, there are on-line communities covering almost all hobbies, interests and
social issues. Setting up and maintaining an on-line community is not always straight­
forward and achieving a critical mass of people with an ongoing shared interest can be
difficult. In this, on-line groups share many of the issues of group formation that are
discussed in Chapter 24. These include getting a critical mass of people, keeping things
up to date and knowing how old some advice is. For example, whilst writing this I was
browsing a site offering recommendations for pizzas in San Diego. The largest blob on
the map represented just 14 recommendations. This is an example of a ‘mashup’, bring­
ing together data from a site with Google maps using a few lines of code that exploit the
Application Program Interface (API) for each dataset.
Individuals can easily create their own comment websites by using one of the many
blog sites such as WordPress (Figure 15.14) or blogspot and contribute to shared discus­
sions and debates using a wiki, a site that allows registered members to add and update
content. The most famous, of course, is Wikipedia, the on-line encyclopedia.

Challenge 15.3

Compare the functions and interfaces of two social networking sites.

Identity 2.0

Sharing and transferring information between people and between sites is all very well,
but it introduces its own problems of identity. In current Web systems identity is managed
through usernames and passwords. These are checked against a directory to see if you
have access to a website. In social media we need a much greater level of management of
identity. I might decide to allow you to see just some of my photos, or hear some of my
music, but there are other parts that are private. I might want to share some of the places I
have visited with you, and some of the details about what I liked, but not all of it.
Identity management is a growing area that strikes at the heart of the social, shared
environments that characterize social media. How can systems be open, how can they
share and how can we network without compromising security and introducing the
possibilities of identity theft? Some Web-based passport or 'driver's licence' is needed
that is accepted by all Web services. How that is going to be achieved is another matter.

Chapter 15 • Social media

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15.4 Sharing with others
A second aspect of social media is sharing with others. With the huge amount of informa­
tion and activity that takes place on the Web, finding what you are interested in and let­
ting others know what you are interested in has become a major issue. The most popular
way of keeping track of photos, videos, or indeed any digital assets is through tagging.
Tagging is concerned with adding keywords to assets so that those labelled the same
can be grouped, shared or used for navigation. Tag clouds such as those in Figure 15.11
(tweettag) is an example.
The creation of tags is sometimes referred to as a folksonomy. Despite efforts to
arrive at a universally agreed set of tags of digital assets (see Box 15.4), informal tag­
ging is most frequently used.

The Semantic Web
The Semantic Web is an initiative of the World Wide Web Consortium (W3C) ‘to create a
universal medium for the exchange of data. It is envisaged to smoothly interconnect per­
sonal information management, enterprise application integration, and the global sharing
of commercial, scientific and cultural data/ The underlying assumption is that objects on
the Web need to be processable automatically by computer. This would enable such things
as artificial agents (Chapter 17) to search out objects and exchange information with them.


Part III • Contexts for designing interactive systems

RDF stands fo r the 'Resource D escription Fram ew ork' w h ich aim s to provide an
application-independent form fo r processing m etadata. W eb O ntology is a standard
W eb classification schem e. Together these are the enabling technologies that would
bring about the Sem antic W eb. The idea behind the Sem antic W eb is to establish a
defined ontology o f objects. This would allo w programs to autom atically locate defined
items o f content that shared an ontology. is a bookmarking application that allows people to store URLs and tags and
retrieve them in different ways. In addition to the personal tags that are attached to a
site, colleagues and others in a personal network can access your bookmarks and add
their own activity. Bookmarks from everyone using can also be accessed by
popularity or by how recent they are. is another site devoted to helping people
share their views of the Web. A simple click allows people to ‘digg’ a site, video or story
and those with the most ‘diggs’ appear hig