Ultimate Guide To Data Science Interviews
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Table of Contents
TableofContents
Introduction
WhatisDataScience?
DifferentRoleswithinDataScience
HowDifferentCompaniesThinkAboutDataScience
1Earlystagestartups(200employeesorfewer)lookingtobuildadataproduct
2Earlystagestartups(200employeesorfewer)lookingtotakeadvantageoftheirdata
3MidsizeandlargeFortune500companieswhoarelookingtotakeadvantageoftheir
data
4Largetechnologycompanieswithwellestablisheddatateams
IndustriesthatemployDataScientists
GettingaDataScienceInterview
NinePathstoaDataScienceInterview
TraditionalPathstoJobInterviews
1DataScienceJobBoardsandStandardJobApplications
2WorkwithaRecruiter
3GotoJobFairs
ProactivePathstoJobInterviews
4AttendorOrganizeaDataScienceEvent
5FreelanceandBuildaPortfolio
6GetInvolvedinOpenDataandOpenSource
7ParticipateinDataScienceCompetitions
8AskforCoffees,doInformationalInterviews
9AttendDataHackathons
WorkingwithRecruiters
HowtoApply
CVvsLinkedIn
CoverLettervsEmail
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HowtogetReferencesandYourNetworktoWorkforYou
PreparingfortheInterview
WhattoExpect
1ThePhoneScreen
2TakehomeAssignment
3PhoneCallwithaHiringManager
4OnsiteInterviewwithaHiringManager
5TechnicalChallenge
6InterviewwithanExecutive
Whatadatascientistisbeingevaluatedon
TheCategoriesofDataScienceQuestions
BehavioralQuestions
MathematicsQuestions
StatisticsQuestions
ScenarioQuestions
TacklingtheInterview
Conclusion
WhatHiringManagersareLookingFor
InterviewwithWillKurt(QuickSprout)
InterviewwithMattFornito(OpsVisionSolutions)
InterviewwithAndrewMaguire(PMC/Google/Accenture)
InterviewwithHristoGyoshev(MasterClass)
Conclusion
HowSuccessfulIntervieweesMadeIt
SaraWeinstein
NirajSheth
SdrjanSantic
Conclusion
7ThingstoDoAfterTheInterview
1Sendafollowupthankyounote
2Sendthemthoughtsonsomethingtheybroughtupintheinterview
3Sendrelevantwork/homeworktotheemployer
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4Keepintouch,therightway
5Leverageconnections
6Acceptanyrejectionwithprofessionalism
7Keepuphope
TheOfferProcess
HandlingOffers
CompanyCulture
Team
Location
NegotiatingYourSalary
FactsandFigures
TakingtheOffertotheBestFirstDay
Templates
Reachingouttogetareferral
Followingupafteraninterview
Resources
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Introduction
WhenwefirstwrotetheSpringboardCareersGuidetoDataScience,wedidn’texpectthe
engagementit’dgarner.Thousandsofpeoplesignedupinafewdays,confirmingourbeliefthat
therewasascarcityofgreatadviceonwhatisanexcitingbutnebulousfield.
Inspeakingwithmoreandmorepeople,wefoundonlyafewgreatresourcesthatexplainedhow
tobreakintoadatasciencecareer.Therewereindividualstoriesandcollectionsofinterview
questions,butwecouldn’tfindafullguidetocovereverythingaboutthedatascienceinterview
processfromhowtogetaninterviewinthefirstplacetohowtodealwithanyofferedpositions.
Iwantedaguidecollectingperspectivesfrompeopleonbothsidesofthetable.Iwantedtotalkto
recruiterswhorefercandidates,hiringmanagerswhotableoffers,andcandidateswhohad
successfullymadeitthroughthedatascienceinterviewtodemystifythedatascienceinterview
processwithinsightsfrompeoplewhohadpreviouslygonethroughtheprocess.Icoauthored
thisbookwithSriKanajanaseniordatascientistinNewYorkCityatamajor
investmentbank.
AtSpringboard,we’vetaughtthousandsofdatascienceaspirantsthroughourmentored
workshops.Webuiltlarge,engagedcommunitiesofmentorsandalumni,whichaffordusaunique
vantagepointtodeliverreallifeperspectivesonthedatascienceinterviewprocess.
Itwasdifficultcollectingeverythinghere,likeitwasdifficultformanyofthecandidateswhomade
itthroughtheprocess.Someoftheleadersindatascience,includingtheChiefDataScientistof
theUnitedStates,hadtogothroughsixmonthsofwaitingbeforetheygotanoffer!Most
companies’datascienceinterviewprocessesaredesignedtoweedoutallbutthemostdetermined
andskilledcandidates.Itcanseem,attimes,likeahurdlepreventinganysanejobseekerfrom
entering.Yet,whiletheinvestmentcanseemimmense,thereturncanbeevengreater.
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Datasciencehasbeencalledthesexiestjobofthe21stcentury.Datascientistsdon’tjustmake
goodmoney;theydrivesignificantsocialimpactfrommappingworldpovertytostopping
pandemicsbeforetheyevenhappen.DatascientistsunearthedtheidentityofBanksy,andthey
masteredtheartofpredictingbasketballscoresinMarchMadness.Workingindatascienceisn’t
aboutjusthavingagoodsalaryandgoodworklifebalance;it’saboutsolvingbigproblemsthat
matter.
Wewrotethisguidebecausewewantedtoyoutogofrombeingcuriousaboutdatascienceto
activelytryingtogetajobinthefield.Wewantedtounearthwhatittakesforyoutomakeit
throughthedatascienceinterviewprocess.Wewrotethisguidebecausewewantyoutorock
yourdatascienceinterview.
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What is Data Science?
Beforeyoulookfordatascienceinterviews,youshouldknowwhatthetermmeansandwhat
you’regettingyourselfinto.
DJPatil,thecurrentChiefDataScientistoftheUnitedStates,firstcoinedthetermdatascience.
Adecadeafteritwasfirstused,thetermremainscontested.Thereisalotofdebateamong
practitionersandacademicsaboutwhatdatasciencemeans,andwhetherornotit’sdifferentfrom
thedataanalyticscompanieshavealwaysused.Whenpeopletalkaboutbigdataandusing
machinelearningtosolvedataproblems,theyareventuringintoawholenewfieldwhoseterms
arebeingdefinedrightnow.
Differentcompanieshavedifferingdefinitionsofwhatdatasciencemeans.Individualhiring
managersmaydifferaboutexactlywhatthey’relookingfor;theywillhireandinterview
accordingly.
Thisconfusionmakesthedatascienceinterviewprocessdifficultforalotofcandidates.Data
sciencecanhavevastlydifferentdefinitionsdependingonwhatroleyou’reapplyingforandthe
companyyou’reinterviewingwith.
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Different Roles within Data Science
Let’sgothroughasampledata
scienceprojecttoelaborateon
thedifferentrolesyou’llseein
datascience.Adatascience
teammightbeassignedtouse
deeplearningtoclassifyimages
likeYelp’steamdid.
Millionsofphotosareuploaded
onYelpeverysingleday,butit
canbehardtogetimagesyou
wantforeachrestaurant.
Sometimes,thephotos
uploadedareallofthesame
category–maybethey’reall
photosofthefoodorthe
outsideoftherestaurant.A
holisticevaluationofa
restaurantrequiresimagesofdifferentkinds.
Youcanusemachinelearningtoautomaticallycategorizewhichimagesfallintowhatcategory.
Computerscan,withthehelpofatrainingset,tellyouwhetherornotanimageistheoutsideof
therestaurantoroffood.
Datascientistscreatethemodeltohelpmachinescreatethosedistinctions.Theywouldbeableto
thinkthroughthetypesofdatatheyneed,frommanuallytaggedphotostokeywordsinimage
captions.Thistendstobeamoreseniorlevelrole,astheyoftenmanagedataproductsfrom
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endtoendanddealwithallfacetsofdatascienceproblems,fromalgorithmselectionto
engineeringdesign.
Dataengineerscreatesystemstosourcealloftheimagedataandstoreit,aswellasimplement
someofthealgorithmsdeterminedbydatascientistsatscale.Thistendstobearoleforpeople
withstrongtechnicalchopsbutmightnotknowasmuchaboutthetheoryofthealgorithmsthey’re
implementingatscale.
Dataanalystsqueryandpresentthebusinessimplicationsofthechange.Diditpleaseusers?How
muchmoretrafficdidYelpgenerateduetotherecentchange?Thesearequestionsdataanalysts
wouldask.Then,theycommunicatetheinsightstheyfound.Thisroletendstobefilledbymore
entrylevelpeopleandpeopleinbusinessfacingroleslearningtoapplytheirinsightsona
technicalbasis.
Therearemoreroleswe’llcoverindetaillater.Fornow,youshouldknowthatthedatascience
interviewprocessforallthreeofthesegeneralrolescanbevastlydifferentfromoneanotherand
infact,theyoftenare!
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How Different Companies Think About
Data Science
Notonlyaretheredifferentrolesindatascience,therearealsodifferentcompanieswithvastly
differentinterviewprocesses!
Ingeneral,theserolescanbesplitintofourroughcategories.
1Earlystagestartups(200employeesorfewer)lookingto
buildadataproduct
WelcometothebeatingheartlandofSiliconValley.Theearlystagestartupisaromanticnotion,
butoneseeingastaggeringamountofsuccessinarapidamountoftime.Ifyoujoinanearlystage
startup,bepreparedtowearalotofhatsandpotentiallytakeonallthreedatasciencerolesatthe
sametime.Youwillneverhavetheresourcesyouneedinfull,sobepreparedtobescrappyand
tough.
Thebarwillbeespeciallyhighifthestartupinquestiondealswithdataasitsproduct.Aplatform
optimizingotherpeople’sdataorappliesmachinelearningtodifferentdatasetswillhavemuch
higherstandardsforhowtheythinkaboutdatathancompaniestryingtolearnfromtheirown
data.Thecofounderswilllikelybepioneersinthefieldofdatascienceorhaveledlargescaledata
scienceteams.TheywillbelookingforAplayerswhohavesignificantexperienceinthefieldor
tonsofpotentialanddrive.Ifyoujoinanorganizationlikethis,bepreparedforthelearning
experienceofalifetime,andbepreparedtobeheldtothehigheststandardpossiblewhenitcomes
todatascience.
Examplesofthiscompanytype:Looker,ModeAnalytics,RJMetrics
Samplejobpostings:DataAnalyst(Looker),SeniorAnalyst(ModeAnalytics)
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Sizeofthecompany:143associatedonLinkedIn(1150companysize)
Howtoreadthisjobdescription:Focusoncommunicationandscriptinglanguagesfor
queryingandvisualizingdataindicatesthisisabusinessfacingrolewhereinsightsmustbe
communicatedtorelevantteams.
2Earlystagestartups(200employeesorfewer)lookingto
takeadvantageoftheirdata
Thebarwillbelowerifastartupismerelylookingtotakeadvantageofitsdataratherthanselling
adataproducttoothercompanies,butsincethesmartuseofdataisessentialtothecompetitive
advantageofastartup,youshouldstillexpectarelativelyhighbar.
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Startupsinthetechindustrycontainalotoftechnicaltalent,buttheyneedsomebodytobridge
thebusinessandtechteams,especiallyiftherearecommunicationissuesbetweenthedifferent
teamsonhowdataisused.Bepreparedtoworkhardforthecompanytoembracebeing
datadrivenatalllevels,andbepreparedtobetheonewhobringsinnewtoolsandprocessesfor
collectingandusingdataatalllevelsoftheorganization.
Workingforacompanythatdealswithitsowndatabutdoesn’tthinkaboutdataatscalemaybe
anuniquechallengeasyou’llbecalledupontoenforceandspreadadatadrivenculture
throughouttheorganization.Bepreparedtoexerciseyourleadershipandcommunicationskills.
Lastly,B2BstartupsandB2Cstartupsdifferentiateinthedatatheyget.B2Bstartupsare
businesstobusiness;theysellsoftwaredirectlytolargecompanies.ThinkSalesforce.B2C
startupscatertomanyindividualcustomers.ThinkAmazon.Whenyou’redealingwithB2B
startups,you’relikelygoingtobefacedwithdatachallengesthataresmallinvolumebuthighin
detailandfeatures;startupsthatselldirectlytobusinessesdon’thavemanycustomers,butthey
focusmaniacallyontheonestheydohavesinceeachindividualcustomerwillbringinlotsof
revenue.B2Cstartupswillhavemoredataproblemsdealingwithvolumeandscaleastheywill
havemanymorecustomers,butthefocusonindividualcustomerswillbedilutedtofocuson
groupsofthem.AB2Bstartupmaydealwith1,000customers,allofwhompay$1,000amonth.
AB2Cstartupmaydealwith100,000users,buteachusermayonlygenerate$1inrevenuea
month!
Befamiliarwiththecompanyyou’reapplyingforandtheuniquedatachallengesitfaces.Research
thoroughly,andmakesureyou’reonlyapplyingforcompaniesthatfityourpassionsandskills.
Examplesofthiscompanytype:Springboard,Branch,Rocksbox,Masterclass,Sprig
Samplejobpostings:LeadDataScientistatBranch,DataScientist(Research)atRocksbox,,
DataScientistatMasterclass
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Sizeofthecompany:37associatedonLinkedIn(1150companysize)
Howtoreadthisjobdescription:Lookingforageneralistwhocandivedeeperandstill
communicatedifferentinsightsindicatesthisisadatascientistrolethatwillbeverybroadin
termsofskillsetsdemanded.Thisroleisgoingtobeproactiveandentrepreneurial.
3MidsizeandlargeFortune500companieswhoare
lookingtotakeadvantageoftheirdata
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Thelargestcompaniesintheworldknowthattakingadvantageoftheirdataisatoppriority.Some
willhaveestablisheddatascienceteamsthatarewellfunded,robust,andfedwithlotsofdata.
Somewillhavestartupliketeamswithintheorganizationtohelpthemtranslatetheirdatainto
businessinsights.Therearealotofcompanieshiringdatascienceteamsuponrealizinghow
importantdataistoremainingcompetitive.Usethistoyouradvantage;itcanbeeasierpassing
thedatascienceinterviewforalarge,prestigiousbrand.
Whilealotofthesecompanieswillhaveestablishedcorporateculturesandbureaucraciesthat
makeithardertoinnovate,theywillalsohavedataonmillionsofpeople.Imagineprocessing
logisticsdataforWalmartyouwillhavemillionsofdatapoints,andyourinsightswillmakea
differenceinthelivesofmillionsofpeople.
Whilethesecompaniesarenottraditionallyseenastheonesbuildingcuttingedgedatascience
solutions,thereisstillalotofgoodworkavailableforthosewhowanttoworkonchallenging
datasetswithtalentedteammates.
Examplesofthiscompanytype:Walmart,JPMorgan,MorganStanley,CocaCola,Capital
One
Samplejobpostings:DataScientist,ModeleratMorganStanley,DataEngineeratCapitalOne
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Sizeofthecompany:~30,000associatedonLinkedIn(10,000+companysize)
Howtoreadthisjobdescription:FocusonBigDatatoolsindicatesthatthisisgoingtobea
fairlyspecializedrolethatlooksintohandlingtheimmenseamountsofdataCapitalOneis
holding.
4Largetechnologycompanieswithwellestablisheddata
teams
Largetechnologycompaniesareabreedinandofthemselves.They’rethecontinuationofthe
startupobsessionwithdata,exceptnowtheyhavescaledtoapointdealingwithmillionsofdata
pointsormore.ThinkoftheUbers,theAirbnbs,theFacebooks,andtheGooglesoftheworld.
Withlargetechnicalteamsledbysomeofthemostbrilliantmindsintheindustry,datascience
roleshereareheavilyspecialized,andyou’llworkoncuttingedgeproblemswithdatathat
requiresferociouslyinnovativethinking.
Comehereifyoucraveachallengeandifyouwanttolearnalotwithalotofdatapoints.The
upsideisn’tasgoodastheearlierstagestartups,butyou’llgetgoodperks,goodsalary,andgreat
teammatesandagreatCVjobdescriptionincaseyoueverwanttomoveon.
Examplesofthiscompanytype:Facebook,Google,Airbnb
Samplejobpostings:DataScientist,Oculus,DataScientistAirbnbMachineLearning
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Sizeofthecompany:~16,715associatedonLinkedIn(10,000+companysize)
Howtoreadthisjobdescription:Focusonmultifaceted,innovativeskillsetshowsthisis
goingtobeanopenendeddatasciencerolethatwillbeexpectedtothinkofnewprojectsandlead
themfromendtoend.
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Industries that employ Data Scientists
Datasciencealsovariesdependingontheindustry.Industrieshavecertainareasofknowledge
specifictotheindustryitself,andtheyinvolvedifferenttypesofdata.Aschoolwillbefocusedon
differentmetricsthanabank.
Ifyouhappentohaveapassionforacertainindustry,makesureitcomesoffwithkeywordson
yourCVandLinkedIn.Demonstratingwhyyouloveacertainindustryanddeepknowledgeofthe
industryitselfpositivelydifferentiatesyouasacandidate.
ThethreelargesthiringindustriesfordatascienceinO’Reilly’ssurveyofthefieldaresoftware
companies,consultingcompanies,andbanking/financecompanies.Thosethreeindustriesalso
tendtopaythemostfordatascienceprofessionals.
Differentindustriesalsovaryinthetypesofrolestheyhirefor.Software,medicineand
telecommunicationscompaniestendtobethelargesthirersofdatascientists.Software,
aerospace,andinformationtechnologycompanieshiremoredataengineers.Lastly,dataanalysts
tendtobehiredbyhealthcarecompaniesandconsulting/bankingorganizations.
Beawareoftheindustryyourpotentialemployerisin,andinferwhattheirdatascienceneedsare.
Youhavetobeawareofthedifferentroles,companies,andindustrieswithindatascienceto
understandexactlyhowyourdatascienceinterviewprocesswillgo.
Tododatascience,youmustbeabletofindandprocesslargedatasets.You’lloftenneedto
understandanduseprogramming,math,andtechnicalcommunicationskills.You’llalsoneedto
tailoryourskillsetandhowyoupresentyourselftothedifferentrolesandhiringcompanieswithin
theworldofdatascience.
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Mostimportantly,youneedtohaveasenseofdeterminationtounderstandtheworld
throughdataandnotbedeterredeasilybyobstacles.
Thedatascienceinterviewprocessisdesignedtotestforthoseskillsandresilience.Bepreparedto
bechallengedoneverydimension.
GettingaDataScienceInterview
Thefirststepinthedatascienceinterviewprocessisn’tdealingwiththeinterview;it’sfindingitin
thefirstplace,aprocessthatinandofitselfcantakemonthsofeffort!
Wesurveyedabouttwentypeopleaboutthehardestpartsofthedatascienceinterviewprocessas
partoftheresearchforthisbook.Theanswerwegotbackhadlittletodowiththetechnical
questionswethoughtwerethehardest.Whiletechnicalquestionsrankedsecondwith68%of
respondents
selectingitasoneofthehardestpartsoftheinterviewprocess,awhooping80%of
respondents
selectedgettingadatascienceinterview!
Literaturewasscarceoutthereabouthowtogetaninterview,especiallyforpeopletransitioning
fromdifferentcareers.Wediveddeeper,andlookedthroughreallifecasestudiesinadditionto
differentresourceswe’vecuratedforyou.
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Nine Paths to a Data Science Interview
Wefoundtraditionalpathstojobinterviewsthatcouldworktoacertaindegreeindatascience.
Wealsofoundnew,proactiveapproaches,especiallywithemergingstartups,where
nontraditionaltacticscouldgetcandidatestotheforefrontofthehiringrace.
TraditionalPathstoJobInterviews
Ifitain’tbroke,don’tfixit.Whilealotofthenew,proactivetacticswediscusscanhavealotmore
efficacy,it’salwaysgoodtoknowthebasics.
1- Data Science Job Boards and Standard Job Applications
Youcansubmityourresumesandcoverletterstocompanycareerssites.Then,youcanwaitand
hope.We’renotsayingtoavoidthisroute,butitshouldn’tbetheoneyourelyon.
UseIndeedandCareerbuildertosearchfordifferentdatasciencepostings.Then,therearespecific
jobboardsforthedatasciencespace,suchastheKaggleJobsBoard.
2- Work with a Recruiter
Youcancontactrecruiterswhocanhelpputyouintouchwiththerightemployers.Thereare
recruiterswhospecializeindatascienceandtechnologyspaces.Theyaregatekeeperstojobsnever
listedinpublicoutlets.AquicksearchonLinkedInfordatasciencerecruitersnearyouwillhelp
youfindthemostrelevantmatches.
3- Go to Job Fairs
Jobfairsindatasciencearefarandfewinbetween,thoughHarvardandStanforddohost
computersciencejobfairsthathaveplentyofdatasciencejobsfortheirstudents.You’rebetteroff
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attendingeithereventsormeetupswiththelocaldatasciencecommunityratherthanlooking
aroundforyourtraditionaljobfair.
ProactivePathstoJobInterviews
We’vecoveredthetraditionalpathstojobinterviews,theoptionsthathavebeenthedefaultof
jobseeking.Thesedays,gettinganoffersometimesrequireshustleandgritoutsideof
triedandtruetactics.Startupsprovidealargenumberofnewdatasciencejobs.Theircultureand
hiringtacticstrickleduptolargecompaniesthatadecadeagowerejuststartupsaswell.Theresult
isanewhiringenvironmentwhereoftentimes,onehastobeproactivetoreachdecisionmakers
whohaveknownnothingbutgritwhentheybuilttheirowncompanies.
4- Attend or Organize a Data Science Event
Youneedtofindpeopleinterestedinthedatasciencecommunitytofindhiddenopportunitiesand
becomeproactiveatintegratingintothecommunity.Thereareseveraleventswhereyoucando
this,fromlargerconferencestosmallercommunitymeetups.
Conferences
StrataConference
TheStrataConferenceisabigdatascienceconferencethattakesplaceworldwideindifferent
cities.Speakerscomefromacademiaandprivateindustry;thethemesorientaroundcuttingedge
datasciencetrendsinaction.Theconferenceallowsyoutolearnthetechnologybehinddata
science,andthereareplentyofnetworkingevents.
KDD(KnowledgeDiscoveryinDataScience)
KDDorKnowledgeDiscoveryinDataScienceisanotherlargedatascienceconference.It’salsoan
organizationthatseekstoleaddiscussionandteachingofthesciencebehinddatascience.
Membershipandattendanceattheseconferencesoffersamarvelouswaytocontributetogrowing
trendsindatascience.
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NIPS(NeuralInformationProcessingSystems)
NIPS,orNeuralInformationProcessingSystems,isalargelyacademicdatascienceconference
focusedonevaluatingcuttingedgesciencepapersinthefield.Attendingwillgiveyouasneak
previewofwhatwillshapedatascienceinthefuture.
Meetups
We’velistedthemajorconferenceswherethedatasciencecommunityassembles,butthereare
oftensmallermeetupsthatservetoconnectthelocaldatasciencecommunity.
TheSanFranciscoBayAreatendstohavethemostdatameetups,thougheverymajorcityin
Americausuallyhasone.YoucanlookupdatasciencemeetupsnearyouwithMeetup.com.Some
ofthelargestdatasciencemeetups,withmorethan4,000members,areSFDataMining,Data
ScienceDC,DataScienceLondon,andtheBayAreaRUserGroup.
You’llwanttojointheevents,orcreateameetupyourselfifyoucannotfindanearbyevent.Our
directorofdatascienceeducation,Raj,gotajobbybecomingknownasadatascienceconnector.
HehostedalocalmeetupinAtlantaandinviteddistinguishedspeakersindatascience.Soon,he
wasknownasadatascienceinfluencer,andassoonastherewereopendatasciencepositions,he
wastappedtoapply.
5- Freelance and Build a Portfolio
SundeepPattemisadatainnovationleaderattheCaliforniaDepartmentofJustice.He’salso
mentoredforseveraldatasciencecourses,andasadatascientist,heworksoncreatingendtoend
solutionsthatextractvaluefromdata.Hehaspersonalwebsiteswithdifferentdatascience
projects.
Hisbreakthroughintodatasciencecamewhenhefoundanunsolvedprobleminenergy
sustainabilityandworkedtosolveit.Hewassoonapublishedauthorataprestigiousacademic
conference,andshortlythereafter,hewashiredtobecomeapracticingdatascientist.
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Ifyou’reunsureofwhatdatayouwanttoanalyze,wehavealistof19free,opensourcepublic
datasetsyoucanexplore.
Ifyoufreelancearounddataproblemsyouloveandbuildincrediblesolutions,keeparecordof
everythingyoudoinanaccessibleportfoliothattellsstoriesaroundyourpassions.
6- Get Involved in Open Source and Open Data
Themostinterestingprojectsintheworlddon’tnecessarilyresideinsecretivecompanydatabases
anymore.TheyareofteninopensourcerepositoriesonGithub.ThisincludestheNatural
LanguageToolkitproject,whichhelpsdealwithhumanlanguageasadatasourceandthevarious
librariesthatmakeupthePythondatascienceandmachinelearningtoolkit.TheRcommunity
alsohostsmanyofitspackagesonaconsolidatedpublicwebsite.
ManyleadingCTOswillhirebasedonyourcontributiontoopensourceprojects,andmayeven
findyouthroughthatroute.It’seasytotellifsomebodyisabletoworkinateamandbuild
marvelousthingsthroughthetransparentglassofopensource.Makesureyoutakeadvantage.
7- Participate in Data Science Competitions
Ifthebroadconfinesofopensourceprojectsaren’tyourtypeofprojectsandyourcreativitythrives
bestinmoreconfinedsituations,considerjoiningadatasciencecompetition.
DatasciencecompetitionplatformslikeKaggle,DatakindandDatadrivenallowyoutoworkwith
realcorporateorsocialproblems.Byusingyourdatascienceskills,youcanshowyourabilityto
makeadifferenceandcreatethestrongestinterviewassetofall:ademonstratedbiastoaction.
OneofourSpringboardmentors,SinanOzdemir,competedhiswaytoadatasciencejobbasedon
hisworkonproblemsonKaggle.Youcandothesame.
8- Ask People for Coffees, Do Informational Interviews
Attheendoftheday,yournetworkwillgetyouthebestchanceatanewjob.Youshouldseekto
knowmorepeopleinthefieldyouwanttoworkin,ifonlytogetanideaoftheproblemstheyhave
andwhichyoucansolve.
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LegendaryentrepreneurandstrategistSteveBlankhasagreatframeworkforgettingcoffeeswith
peopletoobusytoseeyou,asmostdatascientistswillbe.Youhavetofindawaytoprovidevalue
ofsomekindandlooktogivethemafreshperspectiveontheproblemstheyface.
Thiscanculminateinaninformationalinterviewwhereyouseekadviceandinformationfrom
datascientistsinthefield.Ifyoudothisright,you’llconstantlygrowyournetworkofdatascience
opportunities,andyou’llunderstandmoreabouthowdatascienceworksinindustry.
9- Data Hackathons
Inlinewiththetrendofseeingworkinaction,datahackathonsofferyouanuniqueopportunityto
learndataskillswithamotivatedteam.Youwillhavetosolveadataprobleminacoupleofdays.
AnexampleofthiskindofhackathonistheDataWeekhackathoninSanFrancisco.Byteamingup
withotherstodeliverrealsolutions,you’lldifferentiateyourselffromotherjobcandidates.Many
employerslieinwaitathackathonsaswell,somecompaniesgoingasfarastosponsorhackathon
prizesinthehopesoffindingtheirnextdatascientist!
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Working with Recruiters
ForthissectionweworkedwithAndyMusick,anAtlantabasedrecruiter:contacthimat
andy.musick@hotmail.comifyouwerelookingforanAtlantaareajob.Wealsoworkedwith
AnnaMeyer,adatasciencerecruiteratRobertWalters,arecruitmentagencyspecializedin
datascience.Feelfreetocontactheratanna.meyer@robertwalters.com.
HowtoApply
CV vs LinkedIn
Alotofpeopleouttheremayhaveatraditionalviewonwhatmakesforagoodjobapplication.
They’realreadymissingalargerpoint:thetraditionalviewisout.
Thereisafundamentaldifferencebetweenacademiaandworkinginanindustry,and
itstartsinhowyoupresentyourself.
Wetalkedwithrecruiters,students,andhiringmanagers,andtheyallagreedthatLinkedInwas
thegoldenstandardofrecruitment.HavingawelloptimizedLinkedInprofileallowsemployersto
sizeyouupandrecruiterstofindyoutherightopportunity.
Ifyou’renotmakingsureyoushineonLinkedIn,you’realreadylosingouttocandidateswhoare.
Whilearesumemayberequiredtogothroughtheprocess,itisn’tthemaindrawthatwillgetyou
inthedooranymore.Recruiterswillonlylookthroughyourresumeonceit’spresentedinfrontof
them,whileagreatLinkedIncouldleadtoinboundworkopportunitiesonaconstantbasis.
Unlikeinacademia,whereanimpressivearrayofpapersandacademicworkwillwinover
everythingelse,applyingforindustryjobsinvolvesbeingassuccinctaspossibleandlistingthe
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impactyoudrivewithyouraccomplishments.resumesarenotsomuchreadasscanned.Keepthat
inmindifyou’regoingtobuildone.Arecruiterspendsanaverageofthirtysecondsonaresume.
KeyAdviceonResumes
1) Keepthemshort,preferablyunderapage.Rememberthatpeoplearescanningyourresume
forsignsofinterestbeforetheyeverconsiderdoingadeepdive.
2) Makesureyourskillsstandoutandarehighlighted(considerboldingrelevantskills).
Recruitersandhiringmanagerswilllooktoseeifyou’reatechnicalfitbeforelooking
further.
3) Haveclearjobheadings,andatmost,threeonelinepointsineachoneofyourjob
descriptions.Youwanttoclearlymarkhowyourexperiencetiesinwiththejob
requirementsyou’veappliedfor.
4) Demonstrateyourimpactwithnumbers!Don’tsaythatyou“didX.”Tellthehiring
managerwhateffectsXhad.Youwanttosayyoudiscoveredsomethingthathelped
thousandsofpeoplesavehoursoftimenotthatyousimplydiscoveredsomething.Write
“createdanautomatedsalesemailsoftwarethatgenerated$400,000”not“createdan
automatedsalesemailsoftware.”
KeyAdviceonLinkedIn
1) Don’tbeshy.Filloutasmanydetailsasyoucan;itmakesadifference.Mosthiring
managerswillwanttoseeyourLinkedInbeforetheyeverinterviewyou.
2) Makesureyourjobtitlesareclearandconsistentwithsearchtermsthatrecruiterswould
use.Sayingthatyouworkedasadatascientistorasadataanalystispreferredtocomingup
withyourownjobtitle.
3) Onewayyoucandifferentiatefromothersisaddingsomepersonalflavortoyourprofile.
Addsomeofyourinterestsandpassions,andmakesuretheyareevidentinyourLinkedIn.
Hiringmanagerslikeevaluatingcandidatesfortechnicalskillsandculturalfit.Beingableto
showthatyouhaveyourownuniquetakeontheworldwillonlyaddvaluetoyourjob
searchandhelpyoustandout.
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4) Whileyoumightnotwanttotailoryourprofileforcertainjobsorindustries,makesureyou
knowwhatyou’relookingfor,andmakesurethatcomesoutonyourLinkedIn.Youwantto
beverydeliberateatconstructingyourprofilesothatitgetsyouthepositionyouwant.
Avoidlistingdataentryifyoudon’twanttogetentryleveloffers.Mentionspecific
industriesifyourheartissetonworkingonaparticulartypeofproblem.
Makesureyouknowwhatrolesyou’reapplyingfor,andapplyindustrykeywordsandskill
keywordsthatmatch.Interestedinadatasciencejobinfinance?Don’thesitatetoputindustry
terminologyalloveryourCVandLinkedIn.Ifyouhaveaskillthatyouresearchedisindemandfor
theroleyou’relookingfor,additliberally!Youcanresearchwhattechnologiesacompanyuses;
companieslikeYelpandAirBnBwilloftenblogabouttheirdataprojects.Ifyouseethattherolein
questiondemandsPythonandRskills,makesurethatyourCVandLinkedInmarksthoseskills.
EndorsementsalsoplayapositiveroleinthisregardwhenitcomestoLinkedIn,sodon’tbeshyat
askingpeoplewhohaveworkedwithyoutoendorseyourskillsandgiverecommendations.
MorerecruitersandhiringmanagerslookthroughLinkedInthanresumestoday.Arecruiterwill
lookataCVforanaverageof30secondsbeforediscardingit.Makesuretheimpactyou’vedriven
isfleshedoutwithstrongactionverbs,you’veformattedyourresumeandLinkedIntostandout,
andyou’vefilledthemwiththerightkeywords.
KeepinmindthatthisisafirststepandthatapplyingwithjustaCVorLinkedInwillgetyou
consideredatmostplaces,butnotwithanyparticularenthusiasm.You’llhavejoinedthequeueof
thousandsofothersapplyingthesameway,andyou’llprobablyneedtodomoretogetyourdream
job.Regardless,makesureyouoptimizeeverystepofyourapplication,includingtheCVor
LinkedInthatemployerswillinevitablylookover.
CoverLettervsEmail
Acoverletterwasalwaysthestandardforacademicadvancement.Nowadays,therecruiterswe
talkedtoconfirmedthatcompaniesseldomreadthem.Ifyouwanttodifferentiatewhoyouare,
you’llhavetodoitonyourCVoryourLinkedIn.
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Ifyou’regoingtobeproactive,sendabriefsummaryofwhatyou’vedoneinanemailtoahiring
manager.Thisservesasmoreofanexplainertheycansharewithotherpeopleinthecompany.
You’llwanttokeepitbriefnomorethanafewparagraphsatbestandyou’llwanttokeepthis
emailfocusedonthetopthreepointsthatdefinetheimpactyou’vedriven.
HowtogetReferencesandYourNetworktoWorkforYou
Mostpeopledon’trealizehowcriticalitistobuildandmaintainyournetworktogetyourfeetin
thedoorwiththedatascienceinterviewprocess.Thestrongestsignalhiringcompanieslookforis
strongreferrals,especiallyfrominternalsources.Ifyouhavesomebodyadvocatingforyouinside
theorganizationyou’reapplyingfor,thatcanensurethatyourCVwillbelookedover,anditcan
evengetyoutoskipstepsintheinterviewprocess!
Weinformallysurveyedsomeofouralumsgoingthroughthehiringprocess.Itturnsoutthata
referralfromaninsiderwithinthecompanyledtoa85%chanceofgettinganinterviewwiththat
particularapplication,whilethosewhoreachedoutcoldandonlyappliedwiththeirCVor
LinkedInorthroughthestandardformatonlyhadarounda10%chanceofgettinganinterview.
Pursuingtheformercanimproveyourjobhuntingprocessbyanorderofmagnitude.Ouralums
alsosaidthatthereferraldoesn’tevenhavetocomefromafriend,thefactthatanapplicationhas
beenreferredbyanexistingemployeeoftenguaranteesatleastaphoneinterview
.
Takealongtermviewonthisbyaddingvaluetodifferentpeopleinyournetwork,whether
that’sbeinggenerouswithadviceoncethat’saskedofyouorbeinggenerouswithintroductionsto
otherpeopleinyournetwork.Hopefully,bythetimeyou’relookingforajob,you’llhavebuiltupa
strongnetworkofpeoplealsointerestedindatasciencethatcanmaketherightintroductionsand
giveyoutherightreferrals.
Ifthatisn’tthecase,andyou’relookingtogetthosereferralsrightnow,youcanusewhatiscalled
theinformationalinterviewtechnique.Thisentailsreachingouttopeoplewhoareworkinginthe
fieldtogetasenseofwhat’sgoingonandwhattheirproblemsare.People,evencomplete
strangers,canbeverygenerouswiththeirtimeifyoushowthatyou’regenuinelyinterestedin
whatthey’redoingandyouoffertohelpaswell.
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Lookforpeopleatmeetups,orspecificallytargetpeopleonnetworkssuchasLinkedIn,Angellist
andFounderDating.Presentyourintentionshonestly,butindicatethatyou’reveryinterestedin
thecompanyanddatascienceingeneral.Askforacoffeewhereyoucanaddperspectivetoa
problemthey’resolvingorlearnabouttheircompany.
Asamplescriptmightgoasfollows(whereyoucanaddsomebodyonLinkedInasafriendor
messagethemdirectlyonFounderDatingorAngellist):
Hi[name],
IwassuperinterestedintheproblemsAirbnbisfacingindatascience.I’vebeenaspiringto
breakintothefield,andbeingapassionatefollowerofthe
AirbnbNerds
blog,Inoticedthat
buildingtrustwithdata
isanimportantpartofwhatdrivesAirbnb.Basedonmybackgroundin
psychologyandstatistics,Imightbeabletohelpcomeupwithsomecreativeideasonhowto
fostertrust.
I’dlovetotakeyououttocoffeeandgetagreatersenseofwhatproblemsAirbnbhasperhapsI
canhelp!Wouldyouhavesometimeinthecomingweeks?
Cheers,
[yourname]
LinkstoyourLinkedIn,resume,portfolioand/orarecentproject
Ifyoureachouttoenoughpeopleandseekintroductionstopeoplethroughyournetwork,you’llbe
abletofindpeopleinanycompanytotalkwith.CheckoutyoursecondconnectionsonLinkedIn
andhowtheyareconnectedtoyou,whichyoucaneasilydothroughanyLinkedIncompanypage.
Here’sanexampleofacompanypageforAirbnb.
Onceyou’resetforaninformationalinterview,makesureyou’veresearchedthecompanyandthe
personyou’vetalkedwithbylookingatthecompanywebsiteandanyotherresourcesyoufind.
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Youshouldhaveaprettygoodsenseofwhatproblemsthecompanyencountersonadaytoday
basis.
Theseinformationalinterviewsareagreatchancetoknowexactlywhatishappeningatacompany
andwhattheirprioritiesare,whichisgreatlybeneficialknowledgeinanactualjobinterview.If
youcomeinwellpreparedandpositionyourselfassomeonewhocanhelpthecompany,the
personyou’rehavingcoffeewithcouldbecomeastronginternaladvocateandhelpyoujump
throughtheusualrecruitinghoopstogetyourfirstroundinterview.
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Preparing for the Interview
Hopefullyalltheworkyouputintogettingthedatascienceinterviewpaysoff,andyougetthe
emailthatsignifiesthestartoftheinterviewprocessforyou:acompanyrepresentativebeckoning
foraninitialphonecall.Here’swhatwillhappenandhowyoushouldprepare.
WhattoExpect
Thedatascienceinterviewisacomplexbeast,withbehavioralquestionsmixedwithabunchof
technicalquestions.You’vegottenprettyfarifyou’reabletogetaninterviewinthefirstplace,but
youstillhavefurthertogo.
Let’sstartfromthebeginningadatascienceinterviewwillbevastlydifferentdependingonthe
positionyou’reapplyingforandthehiringorganization.Certainorganizationswillbevery
rigorousandmakeyougothroughseveraltechnicalchallenges.Otherswilllookmoreatculturefit
and,especiallyifyouhavestrongreferences,getyoustraightthroughtothefinalround.
Themostrigorousprocesspossiblelookssomethinglikethis:
1- The Phone Screen
ThiswilltypicallybedonebysomebodyinHRandactsasafiltertosavehiringmanagerstime.
Sometimes,therewillbebasictechnicalquestionstoscreenoutcandidateswhoaregrossly
unqualified,butmostofthetime,thisphonescreeninvolvesestablishingthebeginningsofculture
fitandmakingsurethatthecandidatehasgoodenoughcommunicationskillstocomeoffwellin
theinterview.
Inthiscall,you’llwanttogetasenseofwhatproblemsthedatateamisfacingandthe
organizationalstructureoftheteamyou’reapplyingto.Comepreparedwiththoughtfulquestions
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thatdemonstrateadeepunderstandingofthebusinessandthespacetheyoperatein,andbe
preparedtoaskthemattheend.
2- Take-home Assignment
Afterthephonescreen,companiesoftensendapreparedassignmentforcandidates,withsome
timepressurebeingapplied.Thisisagoodwaytoscreenoutcandidateswhomaybetechnically
weak,orwhomaynotbecommittedenoughtoinvestalotoftimeintherecruitmentprocess.
Somecompaniesdispenseofthisaltogether,butthosethatdoembracethetakehomeassignment
oftenuseitasatestingbartosavetheirhiringmanagerstime.
Anexampleofatakehomeassignmentisdoingadeepanalysisonaspecificdatasetprovidedfor
you.Whentheassignmentisdesignedwell,theassignmentisalsoanopportunitytolearnmore
aboutthetypesofproblemsyouwouldworkonifyouweretogetthejob.Here,you’dbeexpected
tostorytellaroundinsightsyou’dfindinthedata.Anotherexamplewouldbehavingadatasetwith
significanterrorsinitthatyou’dbeexpectedtoclean.Afinalexamplewouldinvolveworkingwith
aspecificproblemrelevanttothebusiness,suchasbuildingajobrecommendationsystemfor
applicantsbasedondatafromjobdescriptions.
Onlythosethatpassthebarofhavinggoodassignmentswilltalktoahiringmanagerfacetoface.
You’llgetweededoutquicklyifyourefusetodoitalltogether.
Takethetimetodotheassignment,andtrytoseehowitrelatestowhatproblemsthecompanyis
undergoing.Usingtheassignmentasawaytoseewhatkindofskillsyou’llbetestedonandhow
thecompanyinquestionisthinkingaboutyourroleensuresthatyoumaximizeyourtime.Thisis
whereyoucanshineinahiringprocessandshowhowyouaredifferentfromothercandidates.
3- Phone Call with a Hiring Manager
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Youmayreceiveanotherphonecallscreenthatwillbefocusedoneithermathematicsand
statisticsquestionsorcodingquestions.Thiswillbedonebyahiringmanageroratechnical
person.Thiswilllikelybethefinalevaluationbeforeacompanyinvitesyoutoanonsiteinterview.
Thephonecallwilltypicallybesplitintothreecomponents.Sometimes,thisisdoneinonelong
call;othertimes,itisdoneinthreeshortphonecallsofaboutthirtyminuteseach.
Mathematical/StatisticalPhoneCall
You’llbeevaluatedoncoremathematicalandstatisticalconceptshere,whichwilldepend
somewhatonwhatroleandwhatcompanyyou’reapplyingfor.Webcompanieswilltendtofocus
onyourknowledgeofA/Bsplittesting,yourunderstandingofhowpvaluesarecalculated,and
whatstatisticalsignificancemeans.Energycompaniesmighttestyoumoreheavilyonregression
andlinearalgebra.Nomatterwhattypeofintervieweryou’retalkingwith,you’llwanttosketch
outtheentirethoughtprocessbehindyourproblemsolving.
Ifyou’reaskedaboutA/Bsplittests,describetheA/Bsplittestprocessindetail,fleshingoutwhat
pitfallstowatchoutforandleaningonanyexperienceyoumighthaveinthefield.Treatthe
questionlikeamathematicalproofandatestofyourabilitytostatisticallyreason,butdon’t
hesitatetoturnyourfinereyestodetailandacoherentstoryaboutwhythismatterstothe
companyathand.
CodingPhoneCall
Thispartoftheinterviewprocessisfairlytypicalandisalsotheclosesttoothertechnical
interviews.You’llbeevaluatedonyourability,overthephone,tosolvecodingchallengesby
presentingeitherpseudocode,orinharderinterviews,compilereadycode.Ifyou’reapplyingfora
dataanalystposition,thiswillswingmoretoaskingyouhowyou’dthinkaboutqueryingdatawith
SQL.Otherwise,you’llbeaskedquestionsintheprogrammingandscriptinglanguagesyou’ve
claimedexperiencein,fromJavatoPython.
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YourinterviewermayalsousetoolslikeHackerRankorCollabedittoevaluateyouliveonline.In
thiscase,yourhiringmanagerwillwatchyouasyoutypeoutyoursolution:bereadyfor
approachessuchasthis,andtrainwiththosetoolsifyoucan!
Thereareplentyofgreatresourcesoutthereforcodinginterviews,fromCrackingtheCoding
InterviewtoInterviewCake.Usethemtoyouradvantage.
Practicemakesperfecthere.Makesureyouhaveacomfortablespaceandnaturalenvironmentfor
youtocode.Bepreparedtojotdowncodeonapaperandexplainitonaphonecall,orbeprepared
totypeinthecodeonalaptop.
Youwilloftenbeaskedaboutdatastructuresmorethananythingelse.Knowhashmaps,trees,
stacks,andqueuesverywell.Prepareforthisphonecalllikehowsoftwareengineerswould
prepareforacodinginterview,andyou’llpasswithflyingcolors.
CallwiththeHiringManager
Finally,you’llbepatchedthroughtothehiringmanager,whoisnowevaluatingyouonhowwell
youcommunicateandifyou’dfitwellontheteam.Thismaybeonaseparatecallfromthe
technicalphonescreens,oritcanbethelastpartofamegacallthatencompassesallthree.Inthis
call,thehiringmanageristryingtogetafeelforyourcharacter,yourmotivation,yourfitwith
theirteam,andyourrawintelligence.Mosthiringmanagershaveamentalmodelforwhotheyare
lookingfor.Thecloseryoufittoit,themorelikelyyouwillpasstoonsiteinterviews.
Thisiswhereyourworkwiththerecruiterbeforehandwillshine.Themoreyouknowaboutthe
problemsthehiringmanagerisfacingandthekindofpersonthey’relookingfor,thebetteryou’ll
bepreparedtopresentyourselfastheperfectfit.Tailoryourcommunicationstothatgoal,andbe
confidentandclear,andyou’llmakeittothenextround.Trytopassthe“airplane”testaswell;
imaginethehiringmanagerevaluatingwhetherthey’dliketospendhoursoftimewithyou.The
workplacewillforceyoutoworktogethercloselyandspendalotoftimetogether.Makesureyou
showthatyoucangetalongwithyourmanager!
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4- On-site Interview with a Hiring Manager
Finally,ifyou’vemadeitthroughtheearliercalls,you’llmeetyourhiringmanagerfacetoface.
They’llbeevaluatingyoufrombothatechnicalandnontechnicalperspective.They’relookingto
ascertainifyou’reafit,andtheymaytestyouonyourtechnicalchopsbyhavingyouwhiteboard
differentscenarios.
5- Technical Challenge
Ifthisdoesn’thappentoyouduringtheonsiteinterview,preparetobechallengedonyour
technicalskillsinoneformoranother,especiallyforrolesthatleanmoretowardsdata
engineering.You’lloftenfindthatthisissimilartoasoftwareengineeringinterviewwhereyouwill
beaskedtowhiteboardandwritedownhowyou’dimplementcertainalgorithmsorsolvecertain
problems.
Hereiswherestrongknowledgeofsoftwareengineeringconceptssuchastimecomplexity/BigO
notationandastronggraspofthemathematicsandstatisticsbehinddataalgorithmscantruly
shine.
6- Interview with an Executive
Ifyoupassthebarforyourhiringmanager,you’lloftendoafinalinterviewwithasenior
executive.Inastartup,thiswilloftenbethecofounderortheCEOthemselves.
Ifyou’vemadeitthisfar,congratulations!Don’ttakeitforgranted,butthisisasignthata
companyisleaningtoanofferforyou.Normally,onlycandidateswhohavepassedthetechnical
barwillgethere,sonowyouneedtoemphasizeexactlyhowyoucandriveimpactwithyour
knowledgeofthebusinessitself,andthespecificproblemsitfaces.Atthispoint,you’renot
lookingtoproveyourselfsomuchastoavoidglaringerrors.
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What a data scientist is being evaluated on
Position Title
Mathemat
ics/Statist
ics (e.g.
P-value
analysis,
AB
testing)
Databas
e
Querying
(SQL)
Algorithm
s (e.g.
Supervise
d learning,
Entity
Resolutio
n)
Software
Engineerin
g (e.g.
Python,
Java,
Object
Oriented)
Big
Data/Systems
Engineering
1
(e.g. Spark,
HBase, Hadoop)
Soft
Skills/Domain
Expertise (E.g.
public speaking,
presentation
skills)
Product Data Scientists
2
Medium
Medium
Medium
High
High
Medium
Data Engineering
Low
Medium
Low
High
High
Low
Data Scientist
High
Medium
High
Low
Low
High
Business Intelligence Data
Scientists
Medium
High
Medium
Low
Low
High
Data Analyst
Low
High
Low
Low
Low
High
Differentdatascienceroleswillhavevastlydifferentexpectationsondifferentskillsets.Whilea
dataengineermightnotbeexpectedtohavemanybusinesspresentationskills,theyareexpected
todominatealltypesofprogrammingchallenges.Conversely,adataanalystwillleanmoreon
theirSQLskillsandnotbeexposedtoheavytechnicalproblems,buttheywillbeexpectedtobe
topnotchpresenters.
Thistableimpliestheindustrydemandanddifficultyofthepositionsfromtoptobottom,with
ProductDataScientistsbeingthemostindemandfortheirspecialized,difficulttoacquireskills.
Knowwhatroleyou’reapplyingfor.Seektoscoutoutexactlywhatneedsacompanyislookingfor
andwhatroletheyaretryingtofityouin;itwillhelpyounavigateandpredicttheirdatascience
interviewprocess.
1Thisismoreinlinewithdealingwithsettinguplargescaledataengineeringplatformsandintegratingvarioustechnologies
together.
2Thesedatascientiststypicallybuildthealgorithmandproductionizeitthroughthedataengineeringinfrastructure.E.g.
Theywouldbuildtherecommendationsystemalgorithmandproductionizetherecommendationsystemliveonthe
platform.
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Here’sahighleveloverviewofthespecificroles:
ProductDataScientist:Endtoenddatascientistwithdataengineeringskills.Productdata
scientistsleadteamstobuildadataproduct.Theytweakalgorithmsandhaveastrongsayinhow
thedataisservedtoendusers.Theywilloftenhavetheengineeringabilitytodeliveronthose
ideas.
DataScientist:Theunicornmixoftechnicalskills,businessskills,andmathematicalknowledge.
Adatascientistunderstandshowtocreateandoptimizedataalgorithms,andhowtoexplaintheir
findings.Theymayneedtoknowlessprogrammingthantheirdataengineerpeers,butthey’ll
neverthelessneedtounderstandenoughtodealwithdataatscale.
BusinessIntelligenceDataScientists:BusinessIntelligenceDataScientistsarefocusedon
gettingbusinessinsightsoutofdata.Theywillunderstandenoughaboutstatisticalmethodsand
differentmachinelearningalgorithmstodifferentiatethemselvesfromdataanalysts.Theybuild
dashboardsandcompletevariousanalyticalstudiestohelpthevariousteamsmakebetter
decisions.
DataEngineering:Adataengineerisn’toftencountedontohaveadvancedknowledgeofthe
statisticsandmathematics,buttheywillhavetoaceeverytechnicalchallengeouttheretoprove
theycandealwithimplementingalgorithmsonmassiveamountsofdata.
DataAnalyst:Anentrylevelrolethatreliesheavilyonmakingoneoffreportsbylooking
throughdataandinterpretingtheresults.ThisroletypicallyrequiresastrongknowledgeofSQL
andExcel.
The Categories of Data Science Questions
Behavioral Questions
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Thedatascienceinterviewprocessinvolvesalotofbehavioralquestions,similartoanyother
interview.Theinterviewerintendstotestforyoursoftskillsandseeifyoufitinculturallywiththe
company.
1. Tellmeaboutadatascienceprojectyouhavedoneinthepast?
Intent:Theintentofthequestionistounderstandthedepthofknowledgeand
contributionsyouhavefromyourpastexperiences.Ittestsyourabilitytotellastory
aroundyourworkandwhetheryoucantieittoimpactonthecompanyyouworkedwith.
HowtoAnswertheQuestion:
■Trytodescribeaprojectthatdemonstratesbothproductandengineering
experience,i.e.theprojectprovidedtheanalyticalinsightandproductionised
theinsighttomakeitactionable.Forexample,ifyouidentifiedkeytopicsina
textdatasetthroughtopicextractiontechniques,youshouldexplainhow
thesetopicsfurtheredcompanygrowthinadataproduct.
■Gointodetailaboutyourspecificcontributionandtheoutcomefroma
businessgoalperspective.Theinterviewerwantstoknowwhatyou
specificallydidwhiletryingtounderstandtheoverallgoaloftheproject.
■Rehearseyourexperiencesmanytimes.Thisisaverycommonquestion,so
have23gotoprojectsyoucangointoextremedetailabouteloquently.
2. Whathaveyoulikedanddislikedaboutyourpreviousposition?
Intent:Theintentofthequestionistoidentifywhethertheroleyou’reinterviewingforis
suitableforyou,andtoidentifywhyyou’removingonfromapreviousposition.
HowtoAnswertheQuestion:
■Understandtherolewell.UsetheHRcontacttogetinsiderinformationabout
theroleanditschallenges.TheHRpersoncanbeatreasuretroveof
informationabouttherole,team,history,andkeyimmediatebusinessgoals.
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■Avoidtalkingaboutissueswithspecificpeople,andbeprofessionalwhen
talkingaboutwhatyoudisliked.Introspectcarefullyandtalktowhatmakes
youpassionate.Forexample,talkaboutderivinginsightsfromdataand
conveyingthemtomanagementinanactionablewayassomethingyouenjoy.
Youcouldalsotalkaboutlearningnewtechnologiesthatmakedatascience
moreactionablethroughtheorganization.Youcoulddislikehowthe
organizationisnotplacingdatascienceatthecenterofitsstrategyorthatthe
companyhashadsignificantattritionattopmanagementlevelandthe
directionoftheteamisunclear.Keepitpositive,pointsoriented,andaway
frompersonalsituations.
● Bad:Ihatedthatdatascientistswerealwaysputbelowtheengineers
andthatmanagementdidn’thaveacluewhatthecompanydirection
was!
● Good:IrealizedIwantedtoworkinacompanywheredatascienceis
partofitscorestrategyandthecompanyhasacleardirection.
3. Tellmeaboutasituationinthepastwhereyouhadtoconvinceothersaboutyourposition
onaspecificmatter.Whatwastheoutcome?
Intent:Theintentistofindouthowgoodareyouatdefendingyourpositionandyour
abilitytoengenderchangewithinateam.
HowtoAnswertheQuestion:Trytofindanexamplewhereyouweresuccessfulat
makingthechangeandthatthechangeisquantifiableinitsimpact.Ifpossible,useadata
sciencetypeexampleifyouhaveone.It’simportantthatyoudemonstrateyour
communicationandleadershipskillshere.
Mathematics Questions
Questionsaboutthemathematicsanglewillcomefordatascientistroleswhereyouareexpected
notonlytoimplementalgorithms,butalsotweakthemforspecificpurposes.
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1HowdoestheLinearRegressionalgorithmfigureoutwhatarethebestcoefficientvalues?
(ThiswasaquestionaskedinC3Energy’sDataScientistinterview)
Rationale:Theintentofthequestionistoseehowdeeplyyouunderstandlinearregression,
whichiscriticalbecauseinmanydatascienceroles,youwon’tjustworkwithalgorithmsinablack
box;you’llimplementtheminsomeway.Thiscategoryofquestion(andyoucouldseeitfromany
typeofalgorithm)testshowmuchyouknowaboutwhatisactuallyhappeningbeyondthesurface.
HowtoAnswertheQuestion:Traceouteverystepofyourthinkingandwritedownthe
equations.Describeyourthoughtprocessasyou’rewritingoutthesolution.
TheAnswer:Atthehighestlevel,thecoefficientsareafunctionofminimizingthesumofsquare
oftheresiduals.Next,writedowntheseequationswhilepayingcarefulattentiontowhatisa
residual.Togofurther,considerthefollowing:
1. Writetheminimizationgoal(ideallyinlinearalgebraic(matrix)notation)ofminimizingthe
sumofsquaresoftheresidualsgivenalinearregressionmodel..
2. Solvetheminimizationequationbyillustratingthatthesumofsquareoftheresidualsisa
convexfunction,whichcanbedifferentiatedandthecoefficientscanbederivedbysetting
thedifferentiationto0andsolvingthatequation.
3. Describethatthecomplexityofsolvingthelinearalgebrabasedsolutionin#2isof
polynomialtimeandamorecommonsolutionisbyobservingthattheequationisconvex
andhencenumericalalgorithmssuchasgradientdescentmaybemuchmoreefficient.
StatisticsQuestions
Agraspofstatisticsisimportantforsolvingdifferentdatascienceproblems.You’llbetestedon
yourabilitytoreasonstatisticallyandyourknowledgeofthetheoryofstatistics.Bepreparedto
reciteyourknowledgeaboutstatisticalconceptslikeTypeIerrorandTypeIIerrorflawlessly,and
bepreparedtodemonstrateyourgraspofdifferentprobabilitydistributions.
1WhatisthedifferencebetweenTypeIerrorandTypeIIerror?(OuralumnusNiraj
encounteredthisquestion).
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Rationale:Companieswillwanttotestyourgraspofdifferentbasicstatisticalconceptstotest
howgoodyouarewiththefundamentalsofstatisticsandseehowyoucommunicatedifferentideas
youmaynotoftenapplywiththesometimestechnocraticlanguageembeddedinstatistics.
HowtoApproachyourAnswer:Benononsense,andcommunicateclearlywhateveryouare
askedtodefine.
TheAnswer:TypeIerroriswhatisreferredtoasa“falsepositive,”ortheincorrectrejectionof
thenullhypothesis.TypeIIerroriswhatisreferredtoasa“falsenegative,”ortheincorrect
acceptanceofthenullhypothesis.Youmaywanttocommunicateyourgraspoftheconceptswith
anexampleandhowitmightberelevanttothebusinessathand.TypeIerrororafalsepositive
wouldbetellingamantheywerepregnant,whileTypeIIerrorwouldbetellingapregnantwoman
theyweren’t.Ifyouwererunningafrauddetectionbusiness,youmighthaveaveryhightolerance
forfalsepositives(aclientwillnotfussaboutanemailonthepotentialoffraud),butafalse
negative(notdetectingfraudwhenitishappening)couldbedisastroustoyou.
2Thiswasaquestionforadatascientistpositionatabiginsurancecompany.Supposea
populationisdividedintotwogroups:aggressivedriversandnonaggressivedrivers.40%of
thepopulationareaggressivedriverswhile60%arenonaggressivedrivers.Theprobabilityof
anaggressivedrivergettinginto3accidentsinoneyearis15%.Theprobabilityofa
nonaggressivedrivergettinginto3accidentsinoneyearis5%.Johnisknowntohave3
accidentsinthepastyear.Whatistheprobabilitythatheis(a)anaggressivedriver,and(b)a
nonaggressivedriver?
Rationale:AlotofcompanieswilltestyourBayesianinferenceskillsasaprimerforhowyou
thinkstatistically.Bayesianprobabilitycontrastswithfrequentistinterpretationsofstatistics,and
yourabilitytoreasonthroughanyBayesianproblemwillshowyouhaveaquickgraspofstatistical
conceptsandthementalmathneededforit.Ifyouneedarefresher,oneofSpringboard’smentors
WillKurtrunsablogcalledCountBayesie,andhehasawonderfulguidetoBayesianstatistics.
HowtoApproachyourAnswer:
TheintentofthequestionistoseeyourlevelofunderstandingBayesianprobability.Sketchoutall
ofyourassumptionsandthecalculationsyou’redoingforyourinterviewerinalogicaland
organizedfashion.
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TheAnswer:Writeoutwhatyouknow.
Probabilityofaggressivedriversinthepopulation=40%or0.4
Probabilityofnonaggressivedriversinthepopulation=60%or0.6
Probabilityofaggressivedriversgettingintothreeaccidentsayear=15%or0.15
Probabilityofnonaggressivedriversgettingintothreeaccidentsayear=5%or0.05
You’llwanttounderstandtheconceptofpriorsandposteriorsforBayesianequations.Aprioris
whatyouaregivenbeforetheproblem,datathatyoureceive.Theprobabilitythatsomebodyisan
aggressivedriverinthepopulationisapriorassumptiongiventoyouthatyoucannotchange.The
posterioristheprobabilityyouderivefromusingtheBayesRuleontheseassumptions(P(A/B)).
BayesRule
Thefirstquestionis“whatisthechanceJohnisanaggressivedriverifhe’sbeenin3accidentsa
year?”
Visually,you’rereallytryingtodrawaVenndiagramofprobabilities:ofallofthepeoplewhohave
beenin3accidentsayear,howmanyareaggressivedrivers?Howmanyarenot?
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Thereisa67%probability(really66.66%repeating)thatsomebodywhogetsintoa
3accidentsayearisanaggressivedriver.Thisisnowyourposterior.
Theprobabilitythatsomebodywhogetsinto3accidentsayearisnonaggressiveis
justtheflipsideofthat.10.6666=0.33333repeating,or33%probability.
3Whatisprobabilitydistributiontype(orshowthederivationofthepdf)youwoulduseto
describethefollowingrandomvariables?
a. Probabilityofkcustomersarrivingtoarestaurantwithinadurationoftminutes
b. TheprobabilityoftheheightofapersoninacrowdbeingatleastXinches
c. Theprobabilityofthesumoftwo6sidedfairdicesbeingY
d. TheprobabilityofhavingkheadsthrownoutofNcointhrows
Rationale:Thisquestiontestsyourknowledgeofprobabilitydistributionsandtestswhetheror
notyouknowwhatmodelstousegivenhowyourdataisorganized.
HowtoAnswertheQuestion:Explainyourassumptionsaboutthedataandthedetailsofhow
thedistributioninquestionfitsthemodel.Beabletovisualizedistributionsandexplaintothe
interviewerwhythedistributionyouvisualizefollowsthemodel.
Answer:
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a. Poissondistribution.Thisisassumingthatcustomerarrivalsareentirelyindependentfrom
eachother.
b. Normaldistribution.NotethatinacontinuousdistributionthelikelihoodofbeingexactlyX
inchesiszero.
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c. P(sum(x1+x2)={0,1,(2,12),(3,11),(4,10)...36})={0,0,1/36,2/36,3/36,…}.Youcanplotthis
outwherethexaxisisthesum,andtheyaxisistheprobability.Illustratethatthisisa
probabilitymassfunctionvsacontinuousprobabilitydistributionfunction.
d. Binomialdistribution.P(kisthenumberofheadsinNthrows):
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Notethatthisvisualizationsaysthereisa25%chanceyouwillget5coinsoutof10tobeheads.
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CodingQuestions
Alargepartofadatasciencerole,especiallyifitismorefocusedtodataengineering,is
programmingtoimplementalgorithmsatscale.Bepreparedtofacesomethingsimilartoa
softwareengineeringinterviewwhereyou’llbetestedonyourexperiencewiththetechnicaltoolsa
companyusesandyouroverallknowledgeofprogrammingtheory.
1SQLGivenatableoftransactions(Transaction_ID,Item_ID,quantity,purchase_date
(MM/DD/YY))andanothertableofprices(item_ID,price),givethefollowinginformation:
1. Totalrevenue
2. Totalnumber/average/standarddeviationofpurchasequantitiesforthesetofweekdays
(MondayFriday)orderedbydescendingnumberofpurchases.
3. Numberofitem_ID’sthatwereNOTpurchasedintheweekdays.
Exampletableoftransactions(definedastransactions):
Transaction_ID
Item_ID
Quantity
Purchase_Date
1
1
5
06/28/2016
2
2
3
06/27/2016
3
2
5
06/27/2016
4
2
1
06/26/2016
Exampletableofprices(definedasprices):
item_ID
Price
1
$2
2
$3
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Rationale:TheuseofSQLtoquerydatabasesisprevalentinlargerstartupsandestablished
companieslookingtoleveragetheircompany.Ifyouareadataanalyst,yourtechnicalinterview
mayexclusivelybeSQLquestions.Understandinghowtogetdatatherightwaycanmakethe
differencebetweengettingajobandnot.
HowtoAnswertheQuestion:Youwilloftenbeaskedtosketchoutyourcodeonpaperor
workwithacollaborativecodingtoollikeHackerEarthwhereyouwillbecodingintheinterpreter
andyourcodeisseenlivebyyourinterviewer.Makesureyoutryforthemostefficientsolution
withasfewerrorsaspossiblegivenashorttimeconstraint.UsesomethinglikeSQLFiddleifyou
wanttopracticeyourSQLqueryingskills!
Answer:
1. SELECTsum(a.quantity*b.price)
FROMtransactionsASa
JOINpricesASbONa.item_ID=b.item_ID
Thiswilljointhepricecolumnfromthepricestableontothetransactionstable,allowingyouto
multiplythequantityofeachitemwithitspriceandthentosumupthatmultiplication.Thiswill
yieldananswerof$37forourtwoexampletables.
2. SELECTDAYOFWEEK(purchase_date),
sum(quantity),
avg(quantity),
std(quantity)
FROMtransactions
WHEREDAYOFWEEK(purchase_date)BETWEEN2AND6
GROUPBYDAYOFWEEK(purchase_date)
ORDERBY2DESC
ThisquerywillusetheDAYOFWEEKfunctioninMySQL,whichreturnsanumberindexofwhich
dayacalendardayis,andreturnsavaluefrom1and7,with1correspondingtoSunday,and7
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correspondingtoSaturday.Filtering,selecting,andthenorderingbydescendingquantities
satisfiesthequestionoftable2.
Ifyouranthequeryonthesampletable,you’dgetthefollowingoutput,with2correspondingto
Monday(June27th,2016):
3. Twoapproaches(usingLeftJoinvs.GroupBy):
a. SELECTCOUNT(DISTINCTA.item_ID)
FROMtransactionsA
LEFTJOIN
(SELECTpurchase_date
FROMtransactions
WHEREday_of_week(purchase_date)IN(Monday,
Tuesday,
Wednesday,
Thursday,
Friday))ASBON
A.Transaction_ID=B.Transaction_ID
WHEREB.purchase_date=NULL
b. SELECTCOUNT*
FROM
(SELECTitem_ID
FROMtransactions
WHEREIsWeekDay(purchase_date)!=TRUEgroupby
item_ID)
Eitherapproachwillnarrowdownatableofitemsthatwerenotpurchasedontheweekend,then
applyaspecialcounttoit.
TipsforSQLQuestions:
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1. Dosmallqueriesfirstinsteadofgoingtothesubqueries.Breaktheproblemdownto
specificintermediatetables,anddothequeriesforthoseintermediatetablesfirst.
2. Becarefulofthecolumnyoudothejoinon.Askwhetheryouwanttokeeprowswhere
therewasn’tamatch(i.e.leftjoinifneeded).
3. Ifyoudon’tknowtheexacttransformationfunction,assumetheexistenceofone,statethe
input/outputtotheinterviewer,andmoveon.
2DevelopaKNearestNeighborsalgorithmfromscratch
(algorithmcoding)
Rationale:Showingyoucanwriteoutthethinkingbehindanalgorithmanddeployitefficiently
inagiventimeconstraintwillbeacriticalwaytoevaluatedataengineeringskills.Thiskindof
questionwillbeaskedofdatascientistswhohaveknowledgeofbothalgorithmsandtheir
technicalimplementation,ordataengineerswhoaregivencontextonwhatisthealgorithm.This
questionscanbeaskedofanyalgorithm,butmostofthetimeinterviewerswilluserKnearest
neighbours,asit’srelativelyeasytocomeupwithcodethatcanwork.
HowtoAnswertheQuestion:First,clarifythequestion.Givenafeaturevector,findthe
euclideandistancefromthatvectortoeveryotherknownvector,andtaketheclassthatisthe
majoritywithintheclosestKvectors.Thisparticularquestiontestsyourunderstandingofmatrix
computationandhowtodealwithvectorsandmatrices.Startbygoingthroughasamplesetof
inputsandoutputs,andmanuallyderivetheanswer.Also,keepaneyeonthetime/space
complexity.Inthesolutionbelow,eachpredictionisofO(2N+NlogN)timecomplexitywhereN
isthenumberofrowsoftrainingdata.
Youwillwanttowritedownyoursolution.Syntaxcounts,andsodovariousfaultsthatwillstop
yourcodefromcompilingproperly,butitdoesn’tcountasmuchasexpressingthelogicbehindthe
algorithm,andshowinghowyoucanapplyalgorithmicthinkingtotheplaneofcomputerscience.
Solution:
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Othercodingquestionscanbemorebigdataspecific.Forexample,askingaboutmapreduceisa
typicalquestioninthecasethatthepositionrequiresanalysisofverylargedatasets.Questions
hereaskhowtotaketheaverageofalargedatasetorfindthemostfrequenteventinanevent
stream.
3HowdoeswordcountmapreduceworkonHadoop?
Rationale:YouwillgetquestionsaboutHadoopandbigdatatoolsifyouindicateonyourCV
thatyouhaveexperiencewiththem,orifthecompanyinquestiondealswithmassivedatasets.
LargerFortune500companiesandtechstartupsthathavescaledbeyondmillionsofusersare
likelytochallengeyouonyouruseofbigdata.Youshoulddemonstrateaknowledgeof
mapreduce,whichcancomefromworkexperienceorplayingaroundwithmassivedatasetson
yourown.HortonhasresourcesdedicatedtohelpingpeoplelearnMapReduceifyouneedto
brushup.
HowtoApproachtheAnswer:Thisquestionseeshowdeeplyyouunderstandthemapreduce
frameworkonHadoop.ThisistypicallydoneusingJava.Althoughthewordcountproblemisan
extremelycommonlyunderstoodone,knowinghowit'simplementedwithintheJavaHadoop
frameworkistheimportantpiecehere.
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Answer:Thedrivercodewouldsetupthejobandconfiguration.IfthedatacomesfromHDFS
andoutputiswrittentoHDFS,addtheinput/outputpathtothejobtothosedirectories.Thenthe
mapperjobwouldtakeeachlineinthefileandemitavalueof1foreachwordasthekey.Notethat
thedatapassedbetweenmapperandreducermustusetheHadoopdatastructuressuchasText
andIntWritablessincethesearemoreefficientforbytearrayserializationvs.primitivetypessuch
asStringsandInts.Themapperoutputwouldthenbecollectedineachexecutor,andthenthe
combinertaskwouldbeexecuted.Thecombinerisalocalaggregatorthatisoptionallysetto
reducetheamountofdatasentbetweenthemappersandreducers.
Onceallthemappersarecomplete,onlythencantheshufflephasebegin.Youmightobserveyour
jobsstuckat33%reducer,whichimpliesthattheshufflephaseiswaitingonthemappersto
complete.Onceallthekeysaresenttothereducersbasedonthisshuffle,thesortphasebeginson
eachreducer.Afterthat,thereducelogicisexecuted,andtheoutputcanbewrittentoanother
HDFSfile.
Commonfollowupquestionsininterviewswouldbetoestimatethetimecomplexityofthis
algorithm,andtheamountofdatathesystemwritesorcommunicatesbetweenmachines.Don’t
forgettotakeredundancyintoaccount,i.e.aHadoopsystemusuallymakesmultiplecopiesofdata
incaseamachinegoesdown.
ScenarioQuestions
1Ifyouwereadatascientistatawebcompanythatsellsshoes,howwouldyoubuildasystem
thatrecommendsshoestoavisitor?(QuestionaskedinVerizonDataScientistInterview)
Rationale:Thisquestiontestshowyouthinkaboutyourworkintermsofdeliveringproducts
fromendtoend.Scenarioquestionsdon’ttestforknowledgeineveryfield;theyaresettoexplore
aproductfrombeginningtodeliveryandseewhatlimitsthecandidatewouldhave.Whilealso
evaluatingforholisticknowledgeofwhatittakestomanageateamtodeliverafinalproduct,this
questionistoseehowthecandidatewouldfitintoateamsituation.
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Typically,datascientistswillbeaskedthisquestion,whiledataengineersoranalystsmightbe
askedforspecificpartsofthescenariorelevanttothem.Dataengineersmightbeaskedtothinkof
howtoimplementacertainalgorithmatscalewithouthavingtothinkofthealgorithmitself,while
dataanalystsmightbeaskedwhatdatathey’dquerytodetermineusers’historicalpreferencesfor
shoes.
HowtoAnswerthisQuestion:Beveryhonestastowhereyoucanaddalotofvalue
(emphasizewhatpartsyou’vehadexperiencein),butdon’tbeshyaboutwhereyouexpecttogeta
littlebitofhelp.Trytorelatehowyourtechnicalknowledgecanhelpwithbusinessoutcomes,and
alwaysenumeratethethoughtprocessbehindyourchoicesandtheassumptionsthatguidethem.
Don’thesitatetoaskquestionsthatcanbettertailorfityouranswer.
Answer:Breaktheanswertotwocomponents:DatascienceandDataengineering
Let'sdiscussthedatascienceelementfirst.Ifitisanewcompanythatdoesnothavemuch
historicaluserdata,gowithitemitemsimilarity.Ifthenumberofdifferentitems/shoesis
extremelylarge,considerusingmatrixfactorizationtechniquestoreducethedimensions.
Ifyouhavehistoricaldataarounduserpreferences(e.g.ratingsofshoes),youcanusea
collaborativefiltertypeapproach.Mentionspecificallytherowsandcolumnsofthematrixyou
generatewitheitherapproach.Thendiscusswhatkindofsimilaritymetricsyouwouldtry.E.g.
euclideandistance,Jaccardsimilarity,cosinedistance.
Afterexplainingthealgorithmicaspect,youwoulddiscussthedataengineeringside.Proposean
engineeringinfrastructurethatscalestomillionsofusers/shoeswhererecommendationsare
generatedinrealtime.Asanexample,youcanstreamtheuserdatatoaS3bucket.Youcan
performthematrixanalysisonanightlybasis,precomputetheentiresetofrecommendationson
aperuserbasis,andstorethisinainmemorydatabasesuchasRedis.Thenyoucouldbuilda
RESTAPIthatwouldquerythedatabaseandrespondwiththerecommendationsgivenauserid.
Question2.HowmuchisthemonetaryvalueofashareofaChange.orgpetitiononfacebook?
(Change.orginterviewquestion)
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Rationale:Theintentofthisquestionistoseehowmuchyouunderstandaboutthebusinessand
howwellyoucanbreakafairlycomplexproblemdowntobasicconceptsandthenconvertthese
conceptstoanalyzablechunksbasedontheavailabledata.Thisisagoodtesttoseehowwellyou
canabsorbacompany’sframeworkforthedataandhowwellyoucancommunicatebusiness
insightsderivedfromyourdataanalysis.
HowtoAnswertheQuestion:Makesureyouresearchthecompaniesyouinterviewfor
thoroughly,especiallytheirrevenuemodel.Getasenseforwhatimportantmetricsthecompany
wouldusetotrackitsperformance,andgetusedtothinkingaboutwhatactionsacompanymust
drivetomakerevenue.Askquestionsandstateanyassumptionsyoumighthave,whichsketchout
howyou’rethinkingaboutthisproblem,thenanswerwithforceandconvictionasifyou’re
presentingtoyoursupervisor.
TheAnswer:ThisquestionrequiressomebasicunderstandingoftheChange.orgbusiness.A
shareofapetitioncanresultinrevenuegenerationintwodifferentways
1. Anotheruserclickingonanadvertisement(i.e.signingapaidpetition)
2. Anewusersigninguponthesystemwhothengoesontoclickonasetofadvertisements
duringthatuser’slifetime
Thefirststepisfiguringoutamethodologythatwouldallowyoutoderiveavalueofbothofthese
ways.Thetrickistostartsimple.Youcansimplifythevalueequationtothefollowing:
Valueofashare=Expectedrevenuefromclickinganad+Averagenumberofnewsignupsper
shareevent*LifetimeValueofanewsignup
Expectedrevenuefromclickinganad=Likelihoodofanadvertisementclick*Averagecostper
clickchargedtopublishers
Likelihoodofanadvertisementclickcanbederivedbyjustlookingatthehistoricaldataand
findingtheaverageconversionrateoverthecourseofatimewindowsuchasamonthoryear.A
similarvaluecanbederivedforthecostperclick.
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FortheLTV,it'salittletricky.Youneedtolookatusersoverthecourseofsimilarlifetimesand
derivetheirtotalrevenuegenerated.Onecommonmethodofdoingthisiscalledthecohort
analysisorretentionanalysis.Youcangroupusersthatsigneduponaspecificmonthandlookat
howmanyofthemclickedhowmanyadsoverthecourseofthenexttwelvemonths.Dothisover
twelvedifferentcohortmonths,andthentaketheaveragerevenueoverthelifetime.Now,the
lifetimetoanalyzecanbesettobehoweverlongittakesthatcauseandeffectrelationshiptobe
considerednegligible,i.e.theuserthatsignedupduetotheinitialsharewouldhavesignedup
anywaybeyondthattimewindow,hencetherevenuegeneratedcannotbesolelyattributedtothe
share.
OnceyouhavetheLTV,plugitintotheoriginalequation,andyouhavethevalueofapetition
share.Therearedeeperelementsyoucangointo,suchastherevenuegeneratedbythenewly
joininguserssharingthemselveswhichcausesotheruserstojoin.Makesurethatifyouaregoing
toincludeadditionalelementstoyouranswerthatitdoesn’tdiluteyourmainmessage.Stay
laserfocusedonansweringtheoriginalquestion.Ifyouhaveassortedthoughtsonthesituation,
leavethemtotheend.
3Givenasetofhistoricalnewsarticlesthathavebeenclassifiedasspecificcategoriessuchas
Sports,Politics,World,howwouldyouclassifyanewarticle?
Rationale:Thisquestionlooksathowdeeplyyouunderstandthedatasciencemethodologyand
yourexperiencewithdealingwithunstructuredtextdata,animportanttestforhowcomfortable
youarewithdataformatsthatmightbedifficulttodealwith.
HowtoAnswertheQuestion:Specifyhowyouwouldorganizethetextandhowyouthinkof
classificationsystems.
Samplesolution:
1. Explorethedataandunderstandkeyelementsofthedata.
a. Plotthedistributionofvariouscategoriesinyourtrainingsettodetermineifthereis
labelimbalance.
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b. Lookatthetexttoidentifyanythingstrange,suchasnonenglishtext,heavy
abbreviations,ormisspellings.
c. Dotopicextractiontoidentifykeywordsforspecificlatenttopicsandfindcorrelation
tothelabelledcategories.Thismaygiveyouahintastowhethertherearelatent
topics(keywords)thatmaycorrelatebetterthanjustusingallthewords.
2. Derivethetrainingsetbycleaningupthetext.Removelesserinformativeelementssuchas
punctuation,abbreviations,andunicodecharacters.Dofurthercleaningbytakingthelower
caseofwordsandlemmatization/stemming.
3. UseaTFIDFvectorizertoconvertthedatatoabagofwordsmodelwithTFIDFmetric.et
lowerandupperboundstoTFIDFtoreducethevocabularysize.
4. Buildapipelinewhereyoucantrainvariousmodelsandcomparetheirperformance
relativetometricssuchasAUC,F1score,precision,andrecall.Youcandogridsearchto
automatethecrossvalidationaspectaswell.
5. Onceyougettheoptimalmodel,youcanpublishthismodeltoproductionusingapickled
model(inpython)orPOJO(injava).Thismodelcanthenbequeriedbyusingtheexact
sameprocessofcleaningasdonein#2and#3forthenewarticles.
4Designanexperimenttofigureoutwhichwebdesignalternativetouse.Assumetherehave
beennootherexperimentsdoneandthereisnoknowledgeoftheuserbehavior.Discusspotential
issuesthatcanoccurwiththeconclusionsandhowtoavoidthem.
Rationale:Manywebcompaniesaskthisquestionbecauseitistheirbreadandbutterto
optimizetheirwebsiteforbetterbusinessresults.ThinkofFacebookconstantlychangingtheir
homepagetogetyoutopostmore.Thedatascientist’sroleisofteninhelpingtheproductmanager
setuptheexperimentorinterprettheexperimentresults.Thegoalofthequestionistoseethe
depthoftheknowledgeoftheintervieweeinthistopic.
Solution:Identifythenatureofthechangeandthemetrictoconsidertodecidewhichversionof
thesitetochoose.Forexample,clickthroughrateandaveragenumberofFacebookshares.
Next,decidethenumberofsamples/visitsnecessarytohitthenecessarystatisticalsignificance
(e.g.95%).Thiscanbedonebyusingachisquaredtest(ifweareusingabinomialrandom
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variableofclickingvs.notclicking)oraztest(ifweareusinganormallydistributedrandom
variable).YoucanthenevaluatethepvaluetoidentifywhetherthemetricoftheBtestis
statisticallysignificantlydifferentthanthemetricofthebaselineAtest.Ifitisandthemetricis
betterthanthebaseline,thenthealternativesiteisthebetterwaytogo.
Someotherissuesyoushouldconsiderinthisanswer:
1) Identifypotentialbiasesduetointeractionsacrosspages.Talktotheproductmanagerand
seeiftherearewaysthatarandomsamplingmaynotworktotestthenatureofthechange
you’reproposingforawebpage.
2) PerformaA/Atestwhichimpliestestingtworandomsamplesofvisitors,andcheckifthe
distributionandmetricofchoicedoesnothaveastatisticallysignificantdifference.This
willensurethefairnessoftheA/Btest.AnA/Atestensuresthatyouraudiencedoesn’thave
aparticularskeworbiasandarandomizedselectionforanA/Btestwillbestatistically
relevant.
3) Whatifthemetricthatweareevaluatinghassignificantoutliersthatmaycausetheaverage
tobeapoormetric?Thedistributionmaybehighlyskewed.Weassumetheaverageisa
goodmetricofcomparisonsincecentrallimittheoremholds.Thismaynotbetrue.Hence,
checkthedistributionofthemetrictoensurethattakinganaverage(e.g.conversionrateor
averagenumberofsharesperuser)isareasonablemetricwhencomparingbetween
alternatives.Ifoneuserhasthousandsofsharesattributedtotheiraccount,forexample,
usingsharerateperusermaynotbethebestperformancemetric.
Insummary,casequestionsaredesignedtotestforyourexperienceandyourknowledgein
differentfieldsofdatascience.Theyaredesignedtoseeifyouhaveanylimitstoyourability.
Demonstrateyourknowledgethoroughly,andyou’llcomeoffwellinanycaseanalysis.
TacklingtheInterview
1) Dressedaccordingly.Ifit’saninterviewforastartup,adressshirtwillsuffice.Ifit’san
interviewwithabank,wearsuitandtie.Ifyou’reunsureofwhattowear,ask.
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2) Beforeyoucomeintotheinterview,researchyourinterviewerandthecompany.Comeup
withgoodquestionstoask.
3) Beatthetopofyourgamementally.Eatwell,behydrated,exercisewell,anddowhatever
youcantomakesureyou’repreparedtohandleaninterview.
4) Answerquestionsindetail,andsketchoutyourthoughtprocess.
5) Smile,andbeconfident.Don’tcomeinstressed.Meditate,stretch,orreaddowhateverit
takestogetyoutoyourpeak.
Conclusion
Thedatascienceinterviewprocessisamultifacetedbeast.You’llbechallengedtoprogramand
comeupwithtechnicalalgorithmsonthespot.You’llbechallengedaboutyourstatisticaland
mathematicalknowledge.You’llbechallengedonyourabilitytoleadteams,communicate,
persuade,andinfluence.
Itcanbehardtoseehowtopassthisbeastofaninterviewprocess.Thankfully,wecondensed
actionableinsightsfromsuccessfulapplicantsandthehiringmanagersontheothersideofthe
table.
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What Hiring Managers Are Looking
For
InterviewwithWillKurt(QuickSprout)
Bio:WillKurtisaDataScientistwithQuickSprout.His
maininterestsareprobability,writing,andHaskell.He
blogsatCountBayesie.comandcanbefoundonTwitteras
@willkurt
Whatdoyoulookforwhenyou’rehiring
candidates?
Thebiggestthingformehasalwaysbeenacombinationof
creativityandgenuinecuriosity.Inastartupenvironment,
newproblemscomeupeverydayinawiderangeofareas.
Onemonthyoumaybehelpingtheproductteamaddnewfeatures.Thenextmonth,you’llhelp
salesimprovetheirprocess,andthemonthafter,you’llbehelpingmarketingrestructuretheir
testingsetup.Themostvaluablecandidatesaretheonesinterestedinallofthecompany’sdata
relatedproblemsandalwaysthinkingofnewandinterestingwaystosolvethem.
What’sthebestpieceofadviceyoucangivetopeoplegoingthroughthedatascience
interviewprocess?
Inmyexperience,allsmallcompaniesandstartupsworthworkingforareexcitedabouttheidea
ofaddinganewdatascientisttotheteam.Theyhopeyourskillsandexperiencewillhelpthem
solvearangeofproblemsthey’vebeenstrugglingwith.Showuptotheinterviewreadytolistento
whatthey’retryingtosolveandgetthemexcitedaboutsolvingproblemstogether.Everychance
yougetaskpeoplewhatthey’reworkingonandgetthembrainstormingwithyouaboutwaysyou
couldmaketheirdaybetter.Therearethousandsofcandidatesouttherewithsuperbquantitative
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skills,butcandidateswhocareandareexcitedareveryrare.Leavetheinterviewwitheveryone
wantingtoworkwithyouonaproject,andthey’llbetheoneshopingyousay“yes.”
Whatkindofinterviewquestionsdoyouliketoask?Whatareyoutryingtotest?
AllIcareaboutishowyourmindworksonceit’sfixeditselfonaninterestingproblem.At
Kissmetrics,Igaveoutanopenended“homework”assignment.Therewasanobviousapproach
totheproblem(buildaclassifier),butImentionedthisandcautionedthatpartofthetestwasto
seeifyoucouldcomeupwithsomethinginteresting.Theresultsoftheassignmentdidn’thaveto
belongorcomplicated.Whatmatteredisthattheystartedaconversationandshowedthatthe
candidatehadgenuinecuriosityinfindingsomethingworthtalkingabout.Giventhatacandidate
cancodeandiscomfortablewithlinearalgebra,calculus,andprobability,theyhavethebasicsto
learneverythingelse.Itisveryhardtoteachsomeonetothinkcreativelyorbecomepassionate
aboutproblems.
WhatisdifferentabouthowKissmetricsandQuickSprouthiredatascientists?
Rightnow,Quicksproutisaverysmallteamintheearlystagesofproductdevelopment,sowe’re
nothiringnewdatascientistsatthemoment.Onethingthataspiringdatascientistsshouldknow
isthatmanystartupsandsmallcompaniesarelookingforadatascientistbutmayhavegivenup
onfindingoneasthesearchprocesscanbeexhausting.OneofourbestcandidatesatKissmetrics
showedupatourdoorandsaid,“Iwanttoworkhere!”Peoplecomingfromacademiaorother
largeorganizationsmightnotbeawareofhowflexiblestartupsandsmallcompaniescanbewhen
itcomestohiring.Ifyouthinkacompanyisdoingcoolwork,connectwiththem.It’shardtomake
abetterimpressiononagroupofpeopleexcitedabouttheirworkthantellingthemyoulovewhat
they’redoingandwanttobeapartofit.Evenifthatcompanyisn’thiring,you’llbeatthetopof
thelistif/whentheydostartlooking.
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InterviewwithMattFornito(OpsVisionSolutions)
Bio:MattFornitoisaDataScientistandLeaderwithover
tenyearsofexperienceintheresearch,analytics,and
managementdomains.Apassionforlearninganddevout
workethiccontinuestohelphimgrow.Thisinterviewis
transcribedfromnotestakenonaphonecallwithMatt.
Whatdoesyoulookforwhenyou’rehiring
candidates?
Ifeelmostcomfortablehiringpeoplewithastrong
quantitativebackgroundwhocanlearnprogramming
ratherthantheotherwayaround.AMastersoraPH.Disveryimportanttome,asIfeelthat
undergradisnotastrongsignalofsuccess;it’sarelativebreezeformostpeople.Ipreferhiring
peopleabletopickupprogrammingandeffectivecommunicationknowingandunderstanding
whatthetechnicalproblemsaretoimplementingasolutionandbeingabletocommunicatethose
conceptsiskey.Whatdifferentiatesdatascientistsanddataanalystsistheabilityofdatascientists
todeeplyunderstanddataproblemsandhowtosolveforthem.
IlikerecruitingMastersandPhDsfrommathandstatistics,chemistry,physics,and
bioinformaticsandengineering.ThereareasmallhandfulofpeopleinMBAsthathaveworked
outgreatforme.IamactuallyaPhDinorganizationalpsychology,sothoughItendtotrytohire
peoplewithSTEMbackgrounds,itisn’tastrictlimitation.
What’sthebestpieceofadviceyoucangivetopeoplegoingthroughthedatascience
interviewprocess?
RecruiterslookateducationlevelandthelasttwojobsontheCVandtheirpedigree.HRsonly
takeaveryquickglanceatCVs,soyouhavetostandoutinamatterofseconds.Onepieceof
advice:getyourselfintoabigcompanythathasapedigreelikeFacebook,orgointoastartupand
takeahighpositionsothatyoucanstandouteasilyforadvanceddatascienceroles.
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“Walkmethroughaproject”questionswhereahiringmanagerwillaskexactlyhowyoubuilt
somethinginthepastarehugeeverythingfromwhatdatawasused,whattoolswereused,what
theoutcomeswereareimportanttorecountclearly.successfulintervieweeshaveacomfortable
grasponwhatthey’veworkedonandarereadytostorytellonthatelementandrelatehowtheir
workimpactedthebusinesstheywereworkingfor.
Whatareyoutestingfor?
QuestionsIaskinvolveworkingaroundaprojecttotestproblemsolvingandcommunication
skillsacrosstheinterview.Iamalsoassessingacandidate’spassionforthecompanyanddata
science.Adriveforcontinuouslearningandloveofproblemsolvingarekeydifferentiators.Then
onthetechnicalside,Iaminterestedinseeingcandidatesworkonhowtooptimizedatawith
HadoopandSparkandworkingonthetradeoffsbetweendifferentdatasciencesolutions.Dothey
thinklikeadatascientist?Havetheydonedatasciencework?TheseareimportantquestionsIam
lookingtouncoverwithmyinterviewprocess.
Iwillthengointomathquestionssuchasaskinghowgradientdescent,statisticaltechniques,and
randomforestwork.Acoupleofsituationalquestionswherethecandidateisputthrougha
hypotheticalclientsituationaredeployedtoseehowthecandidatewouldhandleinterfacingwith
clients.IhaveastrictrequirementofabilitytoprograminPythonorR,butIamflexiblewithC++
andJava.Idon’tbelieveinHackerRankliketestingsituationswhereyouareexpectedtotraceout
asolution;Iwouldrathertestforadaptiontonewprogramminglanguagesandanabilitytolearn
skillsrapidly.Anybodyhiredisgoingtohavetohavethelatentskillofadaptability,andthatis
thekeythingIamtestingfor.
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InterviewwithAndrewMaguire(PMC/Google/Accenture)
Bio:AndrewhasbeenworkinginAnalytics/Data
Sciencefor7yearsinvariousrolesacrossmany
differentindustries.HeisaDataScientistatPenske
MediaCorporationfocusingonbothdata
engineeringinfrastructureaswellasapplied
businessanalytics.Priortothisposition,heworked
atGoogle(marketinganalytics,thenlocaldata
quality),Accenture'sAnalyticsInnovationCentre
(consultancy),andAon'sCenterforInnovationand
Analytics(productdevelopmentteam).
Whatdoyoulookforwhenyou’rehiring
candidates?
Beyondmeetingthebasicrequirementsfromatechnicalandexperiencepointofview,I'dsay
enthusiasm,willingnessandabilitytocontinuallylearnnewthingsarekey..
Agoodattitudeissuperimportant,sosomeonewhoisabletoalsotellmeabouttheirweaknesses
aswellasstrengthsisagoodwaytodrawthisout(sometimessellingtoohardisabitoffputting;
humilityismuchbetter).
Beingapproachable,openandhonestissomethingthat'skeyonthe'teamfit'side.Youdon’thave
toknowtheanswerforeverythingbutbeingabletoworkwithotherstocomeupwithadecent
solutioniscrucial.
What’sthebestpieceofadviceyoucangivetopeoplegoingthroughthedatascience
interviewprocess?
Onthetechnicalstuff,takeyourtime,writestuffdown,andaskclarifyingquestions.Alsodon'tbe
afraidtotellthemifit’sanareayou'venotworkedonbeforeoranalgorithmyou'renotthat
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familiarwith.Beingabletoadmitwhenyourknowledgeislimitedissuperimportantasadata
scientist;continuallylearningisoneofthemostimportantskillsrequired.
Makesureyouhavetwoorthreedatascience'stories'youcanchataboutwithaninterviewerthat
touchonproblemformulation,datawrangling,analysisandinsights,visualizationand
stakeholdercommunication.Trytogetthebalancerightbetweencoolnerdytechnicalstuffand
showingbusinessunderstandingandinsights.These'stories'canbeprojectsfromyourprevious
roles,collegeassignments,orprojectsyoudidonyourowntime.Getgoodatspottingopenings
frominterviewerquestionstouseyourstoriestoshowconcreteexamplesandexperience.Ifind
thatchatting(indetail)aboutprojectsthecandidatehasdoneinthepastisthebestwaytogeta
properfeelforthem(andbestplacetoprobedeeperfrom),somakesureyoumakeiteasyforthe
interviewertobeinterestedandexcitedtoaskyouaboutsomeproject’sorexample’sfromyour
CV.
Whatkindofinterviewquestionsdoyouliketoask?Whatareyoutryingtotest?
What'sthebiggestormostcomplexdatasetyouhaveeverworkedwith?Whatproblemsdidit
create?(Tryingtobeginadiscussionherethatcanleadintojudgingdatawranglingskillsand
experience)
Givemeanexampleofatimewhenyouanalysedadataset,andcommunicateyourfindingsback
tothebusiness.Whatwastheproblemfaced?Whatdidyoufind?Howdidthisaffectthe
business?(Touchontheextractingbusinessinsightsandcommunicatingbacktostakeholders
aspects)
IaskquestionsveryrelatedtowhatisontheCV,soifit'saprojectfromapreviousrolefor
example,Iwantyoutoexplainwhattheproblemwas,whatsortofdatayouused,howyouusedit,
whattheinsightswere,andhowthisallfitsintothewiderbusiness.Choosewhatyouputonyour
CVverydeliberately.Ifyoufindithardtogetallontwopagesthenmaybehavedifferent‘types’
ofcv’syoumightusefordifferenttypesofroles.
Finally,Iaskcandidatestogivemeanexampleofatimewhentheyfailed,thenaddwhatthey
thinkwentwrongandwhattheywoulddodifferentlyinfuture.Thisissomethingthatcomesout
ofHR101,butIliketohearwhattheyhavetosay:)
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WhatisdifferentabouthowGooglehiresdatascientistsfromtherestofthe
industry?
I'mnotsurethereistoomuchofadifferenceanymore.Generallyitdependsonthespecificrole.
Forveryspecializedpositionsthatareoftenmorelikeresearchorfellowshippositions,youwould
getmuchmoredetailedtechnicalquestionsandproblemstodriveintotherelevantareaof
expertiseinveryfinedetail.Formoregeneralistorbusinessrelatedroles,thefocusismoreonthe
rightmixoftechnicalskills,businessunderstanding,workinginteams,andcommunicating
resultstostakeholders.
ThemaindifferenceinGoogleisthatyouhavealotmoreinterviewsandmeetmorepeople,so
behindthescenestherearearound6+peoplewhohaveallmetyouandprobedyoufromtheir
owndifferentangles.Thesepeopleallhaveadifferentviewofyouandyourstrengthsand
weaknessesandmustcometoadecisionandconclusiontogetherthattypicallyinvolvestradeoffs.
Beingabletoshowdecentlevelofcompetenceacrosstheboardasopposedtobeingarockstarin
oneareabutlettingyourselfdowninotherswillgenerallyserveyouwell.Thisiswhereattitude
andbeingeasytogetalongwithcanbemostimportant;evenifyoufallalittleshortononeofthe
competencies,iftheylikeyouandfeelyoucouldeasilygetuptospeedinthatareainafew
months,thenit'slesslikelytobeadealbreaker.
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InterviewwithHristoGyoshev(MasterClass)
Bio:HristoGyoshevistheHeadofBusinessOperations&
StrategyatMasterClass,afastgrowingstartupthatis
democratizingaccesstogeniusandreimaginingonline
education.Hepreviouslyworkedoncorporatestrategy,
businessoperations,andproductstrategyatboth
consumerweb(e.g.Yahoo!)andenterpriseSaaS
companies.MasterClassislookingtohireaDataScientist
&manyotherpositions.Checkoutthedetailsat
careers.masterclass.com/
Whatdoyoulookforwhenyou’rehiring
candidates?
Oneofthemainassetswelookforisadesiretoworkonprojectsacrossaverybroadrangeof
analyticdisciplines–fromquantitativemarketresearchand/ordesigning,conducting,and
analyzingusersurveys,tostatisticalanalysis,tobusinessintelligenceandanalytics.Wealsolook
forcandidateswhoarecomfortablelearningsomethingnewtoremovebottlenecksandkeepa
projectmoving,whennecessary.
Intermsofeducationalbackgroundandexperience,we’relookingforananalyticalbackground
thatcombines1.sufficientknowledgeofstatisticstodeterminewhatisorisn’tavalidstatistical
inference,recognize&preventbiases,etc.;and2.thedesireandabilitytoobtainandworkwith
realworlddata(whichisalwaysimperfect)andderiveactionableinsights.
Someonewhohasaverystrongquantitativebackgroundandabilitytoprocessandanalyzedata
usingExcel,SQL,andPythonorR;whoalsohasexperienceinsocialscienceresearchor
market/userresearch(througheitheracademicorindustrywork);andwhohasexperiencewith
businessreporting/analytics,couldbeanidealcandidateforus.
What’sthebestpieceofadviceyoucangivetopeoplegoingthroughthedatascience
interviewprocess?
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Strivetounderstandandkeepinmindthebroadercontextoftheproblemyouarebeingaskedto
solveortheproblembehindthequestionyouarebeingasked.Wheneveryouareaskedto
performacertainanalysis,orbuildamodel,someoneatthecompanybelievesthatthiswouldhelp
themsolveaparticularproblem.Sometimesyoucantellinadvancethatitwon’t,andsometimes
youcansuggestabetterapproach.Youranalysis/model/otherworkproductwillalwaysbebetter
ifyoustartfromagoodunderstandingofthecoreobjectivesofthe‘clients’ofyouranalysis.(This
appliesasmuchtoquestionsyouareaskedduringtheinterviewasitdoestoprojectsyouare
askedtoworkononceyougetthejob.)
Whatkindofinterviewquestionsdoyouliketoask?Whatareyoutryingtotest?
Weliketounderstandacandidate’spreviousexperiencewithvarioustypesofworkthatweexpect
willberelevanttotheirrole.Thus,wemayaskforexamplesofspecifictypesofprojectstheyhave
workedon,andthenaskthemtowalkusthroughtheirapproachandthinking,thetoolstheyused,
themajorchallengestheyencountered,andhowtheyresolvedthem.
Wemayalsoaskcandidatestocompleteashortprojecttoseehowtheyapproachsomespecific
problem–andyes,tobeabletoseethequalityofadeliverabletheyproduce.
WhatisdifferentabouthowMasterClasshiresdatascientists?
ComparedtomostDataScienceroles,thejobwithusinvolvesverylittlemachinelearningor
algorithms,andonlyminimaldatawrangling,butaverywidevarietyofanalysesthatwould
informabroadrangeofdecisionsabouttheproducts,business,andoperationsofthecompany.
Theworkwould,ofcourse,involvesomeexporting,processing,andanalyzingdatafromvarious
systems,butwouldalsoinvolvebuildingvariouspredictivemodels;designing,conducting,and
analyzingsurveysorexperiments;helpingtodefineandsetupreporting&metrics;and
conductingoneoffanalysesrelatedtovariousaspectsofourbusinessoperations.
Correspondingly,wedon’tneedcandidatestobeproficientinmachinelearningoralgorithms,but
wedoneedthemtobehighlyversatileandfamiliarwithanumberofotheraspectsofdata
analysis.Wealsoneedthemtobewillingandabletolearntoolsormethodstheymaynothave
previouslyused.
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Conclusion
Hiringmanagersacrosstheboardloveitwhenyoudemonstrate:
1) Passionforthecompanyanddatascienceingeneral
2) Anabilitytogetalongwellwitheverybody,whichmayevenhelpyouwithweaknessesin
yourtechnicalability
3) Strongwillingnesstolearnanddemonstratedabilitytorapidlydoso
4) Astrongrecordofpreviousprojectsandtheabilitytorelatepreviousprojectswithimpact
driven
5) Stronganalyticalability
Nowlet’stalkabouttheothersideofthetable:successfulapplicantswhonowworkasdata
scientists.
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How Successful Interviewees Made It
SaraWeinstein
DataScientistatBoeingCanadaAeroInfo,
Springboardgraduate
What is advice you’d have for how to ace
thedatascienceinterviewprocess?
In terms of preparation, I wish I spent more time
thinking about analytics strategy. I prepped hard
on stats, probability, ML, python/R...all the
technical stuff, but was nearly caught off guard
by a straightforward question about how I'd
approach a particular problem given a specified
data set. My answer wasn't as confident as I
would have liked. I'd been so focused on the
"hard" stuff that I hadn't thought that much
about higherlevel analytics methods &
strategies.
What surprised me and what I found
difficult:
How long the process took. I knew to
expect several interviews, and in fact had
three. With nearly a week between each,
plus waiting for my background check to
clear, the process from first contact to firm
offer took a month. It was stressful to say
the least. Staying positive, confident, and
prepared for a whole month was
challenging. It would have been much
easier to bear if I'd known in advance that
it would take that long. For others facing a
lengthy multiinterview hiring process:
meditation is your friend. It helped me
sleep at night, and I used the techniques
right before interviews to channel calm and
confidence.◼
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NirajSheth
DataAnalystatReddit,Springboardgraduate
What is advice you’d have for how to ace
thedatascienceinterviewprocess?
I wish I had studied more fundamental statistics
before interviewing. It's silly, but people often
look for whether you are familiar with terms like
Type I and Type II errors. Depending on the time
you have, I suggest getting a statistics textbook
and at least becoming familiar with the terms out
there.
I should have probably expected this, but I was
surprised how poor we are as an industry in
evaluating projects. When I talked about past
projects, everyone just cared about interest value
(does the analysis say something interesting?)
nobodyquestioneddeeplythemethodsIused.
You didn't ask this, but there were also
some things I did that I think worked out
well. One is to have a live project up
somewhere with a neat visualization (i.e.
more than a github repo with a readme). It
doesn't have to be fancyjust prove you can
build something that works (mine was a fog
prediction map, for example). It definitely
helpsgetyourfootinthedoor.
The other thing is to ask for a takehome
data set. I don't know about you, but I've
found that for myself and other people who
don't have a formal data background, it can
be intimidating to work on a data set on the
spot; I just hadn't developed the muscle
memory for it yet. However, I knew the
right questions to ask, and I could figure
out how to answer them if I had a little
time, so getting a takehome set let me
showwhatIcoulddothatway.◼
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SdrjanSantic
DataScientistatFeedzai|DataScienceMentor
atSpringboard
What is some advice you’d have for how
people can ace the data science interview
process? What were some of the toughest
questions?
The most important thing, in my opinion, is
understanding how the major supervised and
unsupervised algorithms work and being able to
explain them in an intuitive way. A good
command of Data Science terminology is crucial.
Candidates should also have a thorough
knowledge of relevant accuracy metrics, as well
as the various approaches to evaluation
(train/test, ROC curves, crossvalidation). The
tougherquestionswould
relate to these same affairs, but with having
tobreakoutthemathonawhiteboard.
Howdidyourinterviewprocessgo?
Luckily, very smoothly! Most of my
interviews had a feeling of being a
conversation between peers, so I didn't find
them very stressful. The companies I
interviewed with moved very quickly (one
round a week), which helped streamlined
the process. I was also very impressed as to
how most companies that turned me down
gavemeveryhonestfeedbackastowhy!
What were some of the factors for
youinchoosingyourcurrentjob?
Primarily, it was the opportunity to use a
technical toolset and solve problems I
hadn't solved before. My previous role was
very focused on just building models. The
data was already completely cleaned and
preprocessed, and the exploratory work
was done using a commercial GUIbased
tool. I felt that my datawrangling and
command line edge was being dulled slowly
and jumped at the opportunity to work in
an environment where I'll be able to "get
myhandsdirty"oncemore!◼
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Conclusion
Thecommonpointsforsuccessthesedatascientistsbringtotheforefrontareasfollows:
1) Don’tthinkquestionsaboutbasicmaterialwon’tbecovered.Readuponstatistical
fundamentalsbeforeyougothroughtheinterviewprocess.
2) Bepreparedtodowellonnontechnicaldimensions.Companiesaretestingyouonyour
communicationskillsandyourabilitytogetalongwithfuturecoworkersasmuchasthey
aretestingyouonyourstatisticalandprogrammingknowledge.
3) Bepreparedtostorytellaboutwhoyouareandwhyyourpassionsandskillsareuniquely
valuableforthecompanyathand.Havingrelevantprojectsandbeingveryclearaboutwhat
youcontributedtothoseworkswillmarkyouasacandidateworthyofpassingtothenext
round.
4) Bepatient.Aninterviewprocesscantakealongtime.You’llwanttobepreparedtowait.
We’veprovidedyouallthatwehaveontheactualdatascienceinterviewprocess.Nowwehaveto
lookatwhathappensafteryou’vefinishedinterviewing.
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7 Things to Do After The Interview
Afteryou’vefinishedyourdatascienceinterview,youmightthinkyourworkisfinished.That’snot
necessarilythecase.Herearealistofthingsyoucandoaftertheinterviewtoensure,asbestas
possible,thatyoumaximizeyourchancesofmakingthebestlastingimpressiononyourpotential
employers.
1- Send a follow-up thank you note
Itisnowcustomarytosendafollowupthankyounote.Mostrecruitersnowagreethatitis
mandatorytodoso.Witheachofficeworkerreceivinganaverageof110emailsaday,youwon’t
wanttojuststickwithaboilerplate“Thankyoufortheopportunity”email.Howyoufollowupon
aninterviewcanmakethedifferencebetweeninternaladvocatesfightingtogetyouin,and
apathy.
Makesureyou’reremembered.You’llwanttosendanemailattheveryleast.Candidateswhotake
theextrastepofsendinghandwrittennotesoralistofthoughtsaftertheinterviewwillstandout
fromtherestoftheaverage109emails.
2- Send them thoughts on something they brought up in the interview
Oneeasywaytodifferentiateyourselfistogobeyondsayingthanks.Rememberwhathas
happenedintheinterviewandmakeaconsciousefforttoteaseoutexactlywhatpainpointsthe
employeristryingtosolve.Ifsampleproblemswithintheinterviewareorientedtowardsa
technicaldirection,oraquestionnotesadisconnectbetweendifferentteams,you’llwanttomake
anoteofitandsendindepththoughtsonanycompanyproblemsthatmayhavesurfacedduring
yourdiscussion.
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Afterall,aninterviewisn’tjustatest;it’sadiscussion.Ifyoulistencarefullytothequestions
presentedandasktherightquestionsyourself,youwillknowexactlywhatproblemsthecompany
isfacing.Makesureyousendthemthoughtsonwhatsolutionsyou’dpursue.
3- Send relevant work/homework to the employer
Itcanbedifficultseeinghowyourdifferentskillsapplytotheoffice,especiallyforsomebodywho
hasjustmetyou.Thesharpesthiringorganizationswilloftengiveyouasampleproblemtosolve
thatissourcedfromsomerealissuetheyarefacingrightnow.Thisgivesyouthechanceto
demonstratehowyoureffortscanimpactthebusinessinapositivemanner.
Organizationsthatdon’tdothatwillhesitatetohiretherightcandidatebecausetheyhaven’t
sufficientlydemonstratedhowthey’ddriveimpactforthecompanyinquestion.However,youcan
beproactiveandusewhatyoulearnedintheinterviewtofollowup.Youdon’thavetostopat
sendingthemthoughtsthatshowyoulistenedcarefully;youcangivethemactual,tangible
solutions
TheauthorofthispostonForbeswastoldthattheydidn’thaveenoughofaportfoliotogetajob
asafreelancecopywriter.Aftertheinterview,thehiringmanagertoldthemthattheylikedthe
spiritthecandidatehad,butwerehesitantduetoalackofaportfolio.Havinglistenedcarefully
throughouttheinterview,thecandidateknewthatamajorproject(theredesignofawebsite)was
justoverthehorizon.
Insteadofacceptingdefeat,thecandidatesenttenproposedheadlinesforthewebsitebanner,free
ofcharge.Thisburstofinitiativegotherthejobofdoingtherestofthewritingforthe
websiteandtheattentionofaverybusyemployer.
Youneedtohaveaportfoliothatshowstheimpactyoucanmake,butsometimesthatisn’t
enough.Ifyou’reastuteandyouasktherightquestions,youcanfindamajordataproblemforthe
company.Therealwaysissomethingthat’swhythey’rehiringforthefirstplace!There’sadata
projectouttherethateverybodywouldlovetoseedoneorathornyproblemthatnoonecanfigure
out.
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Sendthemaplanforwhatyou’ddoorplaywithsomeofthedatathey’vedivulged,andgivesome
solidinsightsintohowyouwork.Proactiveinitiativewillgoalongwaytogettingyouanoffer.
4- Keep in touch, the right way
Oneofthemostawkwardpartsofthepostinterviewprocessiswaitingforaresponse.Youdon’t
wanttocomeoffasdesperatebyfollowinguptoomanytimes,butcompaniestaketheirtimeif
youdon’tengagewiththemproactively.
Itispossibletoeffectthepostinterviewdecisionfromoutsideofthecompany,butyoushould
keepinmindtheappropriatechanneltoreachsomebody.Makesuretoaskbeforetheinterview
endshowbesttoreachyourinterviewer.Everybodyhasapreferredmodeofcommunication;if
theyspecifyshortemailsortocheckinonceinawhileinperson,followthatruleanddispelsome
ofthepostinterviewawkwardness.
5- Leverage connections
Youshouldhavecomeinwithstrongreferencesbothfromexternalandinternalsources.Ifyou
hadbeenbuildingyournetworkandprovidingvaluetothem,youshouldhavestrongadvocates
thatcansupportyourcandidacy.Checkinwithpeoplewhohavereferredyouinternallyeveryonce
inawhile,andifneeded,getthemtoadvancehowexcitedyouwouldbetoworkatthecompany
andhowluckythecompanywouldbetohireyou.
Hiringisoftennetworkdriven,andthestrongestsignalyoucansendtoapotentialemployerisa
strongnetworkofpeoplewhoarewillingtogotobatforyou.
6- Accept any rejection with professionalism
Nomatterwhat,you’reoftengoingtogetrejected.Sometimes,you’renotrightfortherole,orthey
mighthavefoundsomebodywhoisabetterfit.It’simportantatthispointtomaintainyour
composure,thanktheemployerfortheirtime,andmoveon.
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Peopleintheindustrytalkamongsteachother,andbeingunprofessionalatthispointwillonlybe
badkarmaandmightgetyouignoredatothercompanies.Beingprofessionalensuresthehealthof
yournetwork.Moreimportantly,anoisn’talwaysano.Sometimes,companiesdokeepyour
profileonfileandtheywillreachoutforajobthatistheperfectfitforyou.
PerhapsWinstonChurchillputitbestwhenhesaid“Successistheabilitytogofromonefailureto
anotherwithnolossofenthusiasm.”
J.KRowling,theauthorofthepopularHarryPotterseries,sharedherrejectionlettersfrom
publishers.BrianChesky,thefounderofAirBnB(nowvaluedatmorethan10billiondollars)
publishedsevenrejectionlettersfrompotentialinvestors.Inordertoachievegreatness,youwill
havetoendurerejection.Everybodysuccessfulalreadyhas.
7- Keep up hope
Theinterviewprocesscanbeoneofgreatanxiety.Yourfuturecanbemappedoutbydeciding
whatcompanyyoucanworkfor.Aninterviewcanmeanthebeginningofacareerchange.Itcan
meanmovingcities.Itisaperiodinourliveswhereotherpeoplehaveadisproportionatecontrol
overourdestinies.
Nevertheless,asseenintheprevioussteps,youcontrolalotmorethanyouthink.It’simportantto
keepyourheadupanddowhatyoucan.Themostimportantthingyoucandoduringthe
interviewprocessistokeepuphope.Interviewsarelengthy.Companiestaketimetogetbackto
you.Therearelengthyinternalchecksandprocessesbeforeacandidategetsaccepted.Youmaygo
throughmultipleroundsofinterviewswiththesamecompanyandnotseemanyclosertoafinal
offer.
Youhavetosetexpectations.DJPatil,theChiefDataScientistoftheUnitedStates(aposition
createdforhimbyPresidentObama)tooksixmonthstotransitionoutofacademiatoajobinthe
industry.Youshouldneverbedisheartenedduringyourownjourney.
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The Offer Process
Yourgoalistogetasmanyinterestingoffersaspossiblethatyoucanevaluateandnegotiate.
Whiletheprocessitselfisdifficult,andmaytakelongerthanyoucouldexpect,onceyoustart
gettingoffers,you’llhaveearnedthem.
It’skeytoemphasizehowimportantitistomanageyourexpectationsandkeepyourhopeup.
Severalofthedatascientistsweinterviewedtalkedaboutmonthstohalfayearofwaitingto
transferfromanadvanceddegreefromaprestigiousschooltoasecurejob.Alotofthemhadto
takeentrylevelpositionstogettheirfootinthedoor.
Youmighthaveheardalotofgreatthingsaboutdatascience,butyou’llonlyexperiencethatwith
alotofhardworkandwaiting.
Makesureyouweighwhatispresentedtoyouandchoosethefutureyoudeserveonceyou’ve
spentallthehardworkearningit.
HandlingOffers
Ifyoufinishaprocesssuccessfully,youmighthaveoneofferormultipleoffers.Congratulations!
Acceptinganofferisacommitmentofsignificantamountsofyourtimetothecompanyin
question.Alwayskeepthatinconsideration.Thereareseveralfactorsyoucanusetoascertain
whetherornotanofferistherightoneforyou.
Company Culture
Thismightbeoneofthemostimportantfactorsindeterminingwhenanofferisoneyoushould
accept.Makesureyouaskaboutthekindofcompanycultureyou’regoingtobeapartof.Lookfor
signsthatthecompanyhasindividualsthatgenuinelyenjoyspendingtimewithoneanother,and
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runawayfromgenericdescriptorsandcompaniesthatstruggletodefinetheircultureorwavethat
questionaway.Greatcompaniesinvesttonsoftimeandeffortintomakingsuretheyhave
awesomepeoplewholovewhattheydo.That’llcomeoffinyourquestioning.
YoushouldalsocheckexternalandobjectivesourcessuchascompanyreviewsonGlassdoor.
ApproachcurrentemployeesaswellasformeronesthatyoucanfindonLinkedIntogettheirside
ofthestory.You’lloftenfindcandidtalesthatcangiveyouagoodpreviewofworkingatyournew
jobwouldbelike.
Team
Companycultureisanextensionoftheteamthatinhabitsit,butyoushouldbeexcitedabout
comingtoworkeverydayandworkingwitheverybodyelse.Makesurethatyou’reworkingwitha
teamthatyoucanlearnfrom.Youarethecombinationofthefivepeopleyouspendthemosttime
with,andyou’regoingtobespendingalotoftimewithyourofficeteam.
Location
Makesurethatyou’recomfortablewherethecompanyislocated,especiallyifyou’removing
significantdistances.Youcan’tmovewithoutgreatdifficulty,andit’simportantthatyoufeelat
easewithwhereyoulive.Mattersliketheweatherandthetransitsystemmattertoacertain
degree,especiallyifyou’regoingtolivewiththoseconditionsforyears.
Negotiating Your Salary
Anastonishing18%ofpeoplenevernegotiatetheirsalary,despitethefactthatthosewhodo
typicallyseetheirsalaryraisedby7%.
Whenyoufirstgetyouroffer,you’reatanuniqueleveragepointthatyoumightnotseeagainfor
severalyears.Thisisthetimetotestwhatyou’reworth.Reachoutwithanofferacompanywon’t
fireyouorcancelacontractofferbecauseyouwereassertingyourworth.Initialoffersaresent
withabufferforslightnegotiation.Takeadvantage.
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Duringasalarynegotiation,
1) Comewithawellresearchednumberforwhatyouwant.Looktoindustryaverages,andget
asensefrompeopleworkinginthefieldwhatyoushouldexpect.Nevercomeintoa
negotiationwithoutk
2) Knowingwhatyouwantoutofit.
3) Staypositiveanddon’tpushhardforwhatyou“deserve.”Instead,usethisasapositive
experiencetoassertyourworthandthevalueyoucancreate.
4) Negotiatealittlebithigherthanwhatyouthinkyou’llactuallyget.Anybodyexperiencedat
negotiationwillcomebacktoyouwithacounteroffer,andyou’dbestbepreparedforit.
5) Mostimportantly,don’tfearrejection!Solongasyoukeeptheprocessmovingforward
civillyandprofessionally,acompanywillappreciateyoubeingfrankandpositiveatwhatis
oftenthemostdifficultpartoftherecruitmentprocessforthem.
Beforeyouaccepttheoffer,makesureyouknowhowcommittedyouaretothecompany,team,
andmoney.
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Facts and Figures
Negotiationisalwayseasierifyouhavesomeaveragesalariestogroundyou.Ifyouhavespecific
offerstopropose,you’llbestrongeratthenegotiationtable.
Herearesomefactsandfiguresthatcanstartyourresearch.
Indeed.comcitesanaveragesalaryof$65,000fordataanalysts,anaveragesalaryof$100,000for
dataengineers,andanaveragesalaryof$115,000fordatascientists.Thisvariesfromregionto
region,withthehighestsalariestendingtoclusterinthetechheavyBayArea.Californiahasthe
highestrangeandmedianofallregionswhenitcomesdatascienceaccordingtoO’ReillyMedia.
Globally,theUnitedStateshasthehighestmedianandrangeofdatasciencesalaries,whilethe
UK,NewZealand,Australia,andCanadaaren’tfarbehind.AsiaandAfricatendtohavethelowest
medians.
Thehighestpayingindustriestendtobetechnologyandsocialnetworkingcompanies,whilethe
lowestpayingonestendtobeeducationandnonforprofitsectors.
Thissalaryalsovariesbasedonskillsandtoolsused.O’Reillyhasadefinitivesurveyofhundreds
ofrespondentsintheindustry.Anopenstudy,theresultsindicateavarietyofdifferentfactors
thatleadtodifferentaveragesalaries.Justasanexample,peoplewhousetheScalalanguage
extensively,aspecializedtypeofprogramming,receiveabove$100,000inmediansalary,while
thosewhouseSPSS,aproprietarytool,earnsignificantlyless.
TakingtheOffertotheBestFirstDay
Ifyou’veacceptedanoffer,congratulations!You’veaccomplishedthegoalofthiswholeprocess
andbrokenintothejobyou’vesought,ajobthatpromisesgoodcompensationandtheabilityto
drivesignificantsocialimpact.
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You’llhavetokeepthatmomentumgoingforwardifyouwanttolearnasmuchasyoucan.Be
awarethatcompanieswillworktomakeyouascomfortableaspossible.Youshouldreachoutto
futureteammatesandfigureoutwhotheyareandhowyoucanhelpwiththeirproblemsatwork.
Takethetimetosocializeandmeetasmanypeopleasyoucan.
Moreimportantly,ifyouhavetimebetweenwhenyouacceptedtheofferandwhenyoustart,relax
andenjoy!Makesureyoucatchupwithasmanypeopleasyoucaninyourlife,takethechanceto
rest,andbecompletelyrefreshedforyourfirstdayatwork.
Conclusion
Thedatascienceinterviewprocessisoneofthehardestrecruitmentprocessestocrack,andit’s
oneofthemostcompetitive.Yourfellowintervieweeswillbeadvanceddegreeholders,andsome
ofthemwillhaveextensiveexperienceindatascience.
Whilethefieldisattractingmanytalentedpeople,rememberthatithasaslewofdifferent
industries,challenges,andteamstoworkwith.Ifyouthinkoutsideoftheboxandapplyafew
battletestedtactics,you’llbeabletogetaninterviewandtakeitallthewaytoanofferyoulove.
Splittheprocessintoitscompositesteps,andrememberwhatittakestosucceed.Don’tsearchfor
jobslikeeverybodyelsebyapplyingtothestandardjobpostsandsendingoutforlorncoverletters.
Beinnovativeandsolvecompanyproblemsproactively.Reachouttopeoplewithinthe
organizationforinformationinterviews.Dosomethingdifferentfromthehundredsofother
candidates,andstandoutasagreattechnicalthinkerand,aboveallelse,aproficient
communicator.
Gothroughthetechnicalandnontechnicalpartsofthedatascienceinterview.Onceyou’ve
masteredthethinkingbehindthequestionsandwhathiringmanagersarelookingfor,you’llhave
agoodsenseofhowtoexcelthroughouttheprocess.
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Finally,whenyouhaveanoffer(orseveral)onthetable,takethetimetoevaluatethemwithgood
judgement.Takethetimeafteryouacceptanoffertorelax,skillup,andbringthemomentum
forwardtoyourfirstdayatadatasciencejob.
FinalThoughts
“Most of the world will make decisions by either guessing or using their gut. They will be
either lucky or wrong.”- Suhail Doshi
, CEO,
Mixpanel
“The whole enterprise of teaching managers is steeped in the ethic of data-driven analytical
support. The problem is, the data is only available about the past. So the way we’ve taught
managers to make decisions and consultants to analyze problems condemns them to taking
action when it’s too late.”- Clayton M. Christensen
, management professor at Harvard
“We’re entering a new world in which data may be more important than software.”- Tim
O’Reilly
, Founder,
O’Reilly Media
“Web users ultimately want to get at data quickly and easily. They don’t care as much about
attractive sites and pretty design.”- Tim Berners-Lee
“Data scientists are involved with gathering data, massaging it into a tractable form, making it
tell its story, and presenting that story to others.” – Mike Loukides
, VP, O’Reilly Media
Checklist
1) Mapouttheroleyourskillsfit
2) Mapouttheindustriesandtypesofcompaniesyouwanttoworkfor
3) PrepareyourLinkedIn,CV,andemailtemplates
4) Researcheachcompanyandroleyouwanttoaimforthoroughly
5) Reachoutproactivelytoindividualswithincompanieswithinformationalinterviews
6) Buildstrongnetworksandreferrals
7) Tacklethedatascienceinterview
8) Keepuphope
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9) Negotiateyouroffer
Templates
Gettinganinformationalinterview
Hi[firstname],
IwassuperinterestedintheproblemsAirBnBisfacingindatascience.I’vebeenaspiringto
breakintothefield,andbeingapassionatefollowerofthe
AirBnBNerds
blog,Inoticedthat
buildingtrustwithdata
isanimportantpartofwhatdrivesAirBnB.Basedonmybackgroundin
psychologyandstatistics,Imightbeabletohelpcomeupwithsomecreativeideasonhowto
fostertrust.I’dlovetotakeyououttocoffeeandgetagreatersenseofwhatproblemsAirBnB
hasperhapsIcanhelp!
Cheers,
[yourname]
[Greeting],
[Whyareyouinterestedinthecompany],[somethingthecompanyhasdonethatyoulove],[how
youcanhelp].
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Reachingouttogetareferral
Hi[firstname],
Itwasgreatseeingyouatthepotluck!I’vebeenlookingaround,andI’minterestedinthe
problemsUberisfacing,specificallytheonesfacedbydatascientistsonthegrowthteam.Would
youmindintroducingmetothehiringmanagerorsomebodyontheteamsoIcouldseeifIcould
help?
Cheers,
[yourname]
[Greeting],
[Talkaboutlastpointofcontact],[talkaboutinterestincompanyandproblemsfacedbya
specificrole],[asktobeintroducedtohiringmanagertohelpsolvethoseproblems]
Followingupafteraninterview
Hi[askhowyourinterviewerpreferstobeaddressed],
ItwasapleasuretalkingwithyouaboutGoogle’sdatascienceproblems.IthinkIcanhelpwith
someoftheproblemsyou’veenumerated,andIlookforwardtothenextstepsintheprocess!
Hello[Askyourinterviewerhowtheyprefertobeaddressedduringtheinterview],
[Talkaboutproblemsyoucanhelpsolve],[Statethatyou’relookingforwardtonextsteps]
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Glossary
A/BsplittestAnA/Bsplittestisthegoldenstandardofexperimentdesignforwebcompanies,
wheretwogroupsofusersaresubjectedtodifferenttreatmentsandmeasuredtoseetheir
conversionratetoacertaingoal.Optimizely,awebcompanydedicatedtohelpingrunA/Bsplit
testshasagoodguideontheconcept.
FeatureAnuggetofinformationaboutanobject,usuallystoredasacolumnintabulardata.If
youmeasureandstoretheheight,weight,andgenderofanindividual,youarestoringthree
featuresaboutthem.
LifetimeValueTheexpectedamountofrevenueacustomerisexpectedtogenerateoverthe
timetheyspendwithacompany.Asoftwareasaservicestartupthatsellssoftwarebythemonth
canexpecttocalculatethisbymultiplyingthemonthlypricewiththenumberofmonthsspent.
MapReduceAsetofalgorithmsthatacttoabstractawaythedifficultyofstoringmassivedata
setsbytreatingdatasplitintomultipleserversinawayasintuitiveashandlingitfromone.
MapReduceusesparallel,distributedlogictodealwithmassivedatasets.
OverfittingThetendencyofamodeltofitontopastdata,overgeneralizingfromthoseinsights
tomakeinaccuratepredictionsinthefuture,draggeddownbytheweightofthepast.
TypeIErrorAfalsepositiveistheincorrectacceptancethatsomethingishappeningakinto
tellingamanthatheispregnant.Intechnicalterms,itistheincorrectrejectionofthenull
hypothesis.
TypeIIErrorAfalsenegativeistheincorrectacceptancethatsomethingisn’thappening.Itis
akintotellingapregnantwomansheisn’tpregnant.Intechnicalterms,itistheincorrect
acceptanceofthenullhypothesis.
Formoreglossaryterms,consultthisdatascienceglossary.
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Resources
AparodyoftheinterviewprocessthatexaminessomehardtruthsfromKDNuggets.
Thisbook,calledDataScienceInterviewsExposed,offersmoresamplequestionsthatyoucan
tacklewithyourinterviewpractice.
TheDataScienceHandbookoffersreallifeadvicefromdatascientists,includingsomesmart
analysisonwhatmakesforagreatdatascientistandwhathappensduringtheinterviewprocessto
findthoseindividuals.Itscompanion,theDataScienceInterviewGuide,offers120questionsyou
mightseeinadatascienceinterview.
CrackingtheCodingInterviewisadefinitiveresourceforgoingthroughsoftwareengineering
interviewsandwillhelpwiththeprogrammingpartsofthedatascienceinterview.
ThisQuorathreadgoesintohowAirBnBhiresfordatascientists,aninsightfullookatthedata
scienceinterviewprocessfromanestablisheddatascienceleader.
ThisexposebyTreyCauseyexplainshowtoacethedatascienceinterviewprocessandoffersa
criticalandunvarnishedlookonhowoneshouldapproachthedatascienceinterview.Erin
Shellmanalsotalksaboutherexperiencegettingajobindatascience.
“AsI'vegottenolderandmoreexperienced,Ipushbackininterviews.Iaskquestionsaboutwhat
thepurposeofaproblemisorstatethatIdon'tthinkthisisagoodevaluationofmyskillsor
abilities.SomepeopleprobablyseethisasmethinkingI’m"toogood"toanswerthequestions
everyoneelsehastoanswer,butIseeitasdoingmyparttobeacriticalthinkerabout
evaluation,prediction,andhiring.Hopefullyyou'lldothistooandasmoreofusareinaposition
wherewearebuildingteamsandhiring,we'llthinkmorecarefullyaboutwhatwe'retryingto
accomplishandhowwecangetthereinsteadofcopyingthesamepatternsthathavebeen
aroundforyears.
”
ThisarticleisaninsightfulreadabouthowdatascienceatTwitterworksandofferstheinside
perspectiveofsomebodywhoisadatascientistintheindustry.
Ifyoufindyourselfthinkingaboutprobability,refertothischeatsheettomakesureyou’reontop
ofanyproblem.ThisQuorathreadwillhelpaswell.
EllenChisawritesaboutthingsshehasscreweduponwhenitcomestotechnicalinterviews;you
shouldmakesuretoavoidthosemistakes!
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Finally,FirstRoundReviewhasaprimeronhowtohireexceptionaldatascientists;readitto
knowhowthepeopleontheothersideofthetablethink.
AbouttheCoAuthors
Rogerhasalwaysbeeninspiredtolearnmore.Hebrokeintoacareerindatabyanalyzing$700m
worthofsalesforamajorpharmaceuticalcompany.HehaswrittenforEntrepreneur,
TechCrunch,TheNextWeb,VentureBeat,andTechvibes.
Forthisguide,hecompiledinsightfromSpringboard'snetworkofhundredsofdatascience
experts,includingSriKanajan,hiscoauthor.
SriKanajaniscurrentlyaseniordatascientistinNewYorkCityatamajorinvestmentbank.He
has14yearsofexperienceinvariousengineeringandmanagementcapacitiesandmadeacareer
transitiontobeadatascientistin2013.HecompletedafulltimedatasciencebootcampinSan
Franciscoandprogressedtobecomeadatascientistattwostartupsandeventuallyadatascience
manageratChange.orgbeforetakingonhiscurrentrole.Srialsoteachesparttimeasalead
instructorinGeneralAssembly'sDataSciencecourse.Heispassionateabouthelpingothersmake
thetransitionintodatascience.
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