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92F0094XPE 186 c.1 „..*.„*—:—r;—:—tea—s—- ^^.J—r~ AutomatedCoding Wemayconcludethattrigramcodingcanbea REFERENCE vwmaoolrrukeasbrleiesneotatorohclehrmfsoair^ty.uca_tot.edi.oi.nn_nes.gc.evsesrabrayltro-esC^pAonNjsAe^Ds.A-Hoowe"'veCrA,~iXc''A' NTehteheNreltaMhne.drslaCBneldnasti,rsae1l9B92u3.r.5ea7uofISnttaetriastcitcisv,eVoCorobduirngg. ;fr:~n 1997 B CLLiIZOPTAHReYOUE ! THE7997CANADIANCENSUSOFPOPULATIONEXPERIENCE WITHAUTOMATEDCODING ByJocelynY.TourignyandJoanneMoloney,StatisticsCanada ABSTRACT tobemoreobjectivebyreducingoreliminatingthe artificialstructureofthemultiplechoicesproposed Automationcanimprovethequalityofcodingand (andtheorderofthechoices)therebycountering saveresources.Thepaperdetailsthe1991Canadian therespondents'tendencytocheckonlythefirst CensusofPopulationexperiencewithacodingsoftware relevantchoice; aedxueptvloeolmroaeptdee.ddbcyodSitnatgisitsicjsuCstainfaieddaa(nAdCTtRh)e.bTenheefictesnsaurse twroeh-eoebnxtaanimencienasastvaiaroryni,eotfiytstohmfeodrcielfasispcsoianftsiiecosant;tihoaanntsdctarunctlueraedatnod,a Keywords: automated coding; coding software; - to simplifytherespondents'taskbecausetheir computerassistedmanualcoding;parsing;matching responsesareinthesamemediumasthequestion. census. In ordertofacilitatestatisticaltabulationsand analysis,itisnecessarytogroupthewrittenresponses 1. INTRODUCTION semanticallyusingastructuredclassificationsystem. Thisoperationiscalledcoding. The 1991 Canadian Census of Population completedtheautomatedcodingof1 questionswith Traditionally,codingisamanualoperation.Using write-in responsesusinga softwarecalledACTR thewrittenresponse(andpossiblyotherinformation (AutomatedCodingbyTextRecognition).Inthispaper providedbytherespondent),andcodinginstructions,a we discuss the problems ofcoding in a census codersearchesfortheresponseoranapproximate environmentandtheadvantagesofanautomatedcoding alternativeinthecorrespondingclassificationmanualor system.WereviewthedevelopmentoftheCensus referencematerial.Theassociatedcodeisenteredonthe codingapplicationandACTR. questionnaire.Thiscodeisthencapturedandusedfor subsequenttabulationandanalysis. 2. JUSTIFICATIONOFAUTOMATED Organizingmanualcodingofcensusresultsalways CODING risesmanyproblemsrelatedtothespecificrequirements for personnel, difficulties to ensure quality and Inthecontextofasurvey,questionsrequiring timeliness,andtointegratethecodingoperationinto written responses are useful when the studied censusprocess. characteristichasa largesetofpossibleresponse categoriesorwhensomeoftheoutcomescannotbe Becauseofthat,alternativestomanualcodingwere predicted.Writtenresponsesallowthesurveytaker: sought.Automatedcodingwasselectedbecauseofits potentialtoreducethedependencyoncodingstaffand tosimplifytheformulationofthequestionby reduceoverallcosttosomeextent.Improvementsinthe offeringthe respondentfewermultiplechoice qualityofresultsarisefromthe predictabilityand questions; consistencyofcomputersystems. The1991CanadianCensusofPopulationExperiencewithAutomatedCodings 187 StatisticsCanadahas developedan automated surveyconductedpreviously,oracombinationofthese codingsystemthatcan meettheneedsofvarious two sourcesasinthecaseofthe 1991 Censusof surveys.Thisgeneralizedsystem,knownasACTR,is Population. CuseendsuinssoefveProaplulsautrivoeyns.,thelargestofwhichisthe1991 Figure1.ACTRsystem 3. AUTOMATEDCODINGMETHODOLOGY PhrRaesfeesraenncdecfoidles ResSpuornvseeypfhilreases (ACTRVERSION1.06) 3.1 General Parsing ThemethodsusedbytheACTRsystemarebased inpartonmethodsthatwereoriginallydevelopedatthe Direct US BureauoftheCensus [4] and in parton the match experienceofStatisticsCanadaindevelopingmatching algorithms and systems for administrative files processing.Theresponsetobecodediscomparedtoa saemriaetscohfipsrdee-tceocdteeddrtehsepcoonsrerse,spcaolnldeidngacroefdeereisncreecfoilred.eIdf Imndaitrcehct and the operation is complete. Ifnot, the search continues,andanalgorithmisintroducedtolocatethe most comparableresponse.Once this operation is Results: Results: completed,the systemattributesthe corresponding -Multiplewinners -Winner code. -Possibles -Nocode Thissearchismademorecomplexbecauseofthe factthatthehuman languagehasseveralwaysto erixgphrtesosrdtehre,saanmeimnpootritona.ntWowrorddsamraeynobtealmwiasysisnign,tahne 3.3 Parsing eosAxfyCtpnrTuoanRnncyetoumuaaotsdridowraneobsrbasrdneedsvmsiayatntyhtieaobsxneeomfpaprayernsoneeobnxtltp,ehrmeaassvsewiobotnehr,erdnoourmrgetahshypeecrpbtrueeildoe.ars ciindoednoetTrdidchaaeelrr,epctrhooernsavpeseonernsatsbieelnsdetithnthehasettraeacnfrodeeamrrespndeucimtezaeenrfdtiilfetcooaralmnlr,dyeocterohqgo"unspiieavzraetsl,oeednba,tes" processing(calledparsing)ofresponsesaswellas ACTRprovidestheuserwithahighlyflexibleparsing throughitstwomatchingtechniques. module.First,thephraseisconsideredasacontinuous Figure1depictsthevariousmodulesoftheACTR stringofcharacters;itisnotrecognizedascontaining systemthatweshalldescribe. words,spacesandpunctuationmarks.Thisstringof charactersisanalysedbythesystemtoidentifyseparate 3.2Referencefile words.Theseparatewordsarethenscrutinizedand parsed; the latter stage reduces the problem of Foreachquestiontobecoded,itisnecessaryto synonyms, double words, trivial words, different createareferencefileconsistingoftypicalwritten suffixes,etc. Annex1providesalistoftheparsing responses(calledphrases)forthatquestionandthe functionsofferedbyACTR. associatednumericcode.Ideallythephraseschosenare representativeofthephrasesmostfrequentlyobserved 3.4Directmatching inamatchingoperation.Itisrecommendedthatthe phrasesberetainedintheiroriginalform,witherrorsin Theparsedwordsoftheresponsephraseareputin spelling,grammarandsyntax.Thisfileofphrasesand alphabeticalorderandthephraseiscondensedtoa nfaucmielirtiactecmoadtecshiisnigntoepgerraatteidoinnst.oTahdeatarebfaesreensceervfiinlegtios plhernagsteh;wthhiecrhesualvterisacgaelsle3d5t%heoCfPtKhe(iCnoitmipalrelsesngetdhPohfratshee constructedusingentriesfromstandardclassification Key).Thiskeyisconstructedbyeliminatingspaces manuals, phrasescoded byexpertsfrom a similar betweentheparsedwordsandbyconvertingindividual . 188 AutomatedCoding characters (letters and numerals) and frequent cTohmebikneaytiisotnhsenofucsheadratoctseerasrtcohbfiotrcaonde"erxeapcrte"smeanttacthioinn *=£ Pr7-Y,!-iPrl thereferencefile,whereeachphrasealreadyhasitsown key. isthenumberofoccurrencesofthewordin questioninthephrasesthathavecodei. 3.5Indirectmatching isanarbitrarysmallconstanttoavoiddivision Thismethodconsistsofsearchinginthereference byzerointheeventthat EM= (which filefortheclosestmatchtotheresponsephrasewhena correspondstothesituationwhereawordis directmatchcannotbefound.Allphrasesthathaveone specifictoasinglecode). oprhrmasoerearepaerxstreadctweodrfdrsominthceormefmeornencweitfihle.thTeheressypsotnesme c= log2 evaluateseachofthesephrasesandassignsthema "score." This score, combined with certain pre- 3.5.2Calculatingascoreforeachmatchedphrase te"ihspneotsrspaseibirlbeiildssehb"eaydmatp"htawecrihawnemonseretrkien"srtsoh,mfeaiHtrsecelufhes,lreeedr"nmmctaueolnftdi[ile4ept].leeaTrhnmidwisinKnemnneaweutrhshse[o"t5dh]eo.irrs dcpeoavnresslieEoddapecwrehedodrriednafoeiprrnodetnececrnoettmoifiamdlleoemtpnahertrwacmishite.nhetAhttahhtesecccorolnerotsisapneiogsnntsmspeaehttrplhahesoraedsa;tswetohaniisess 3.5.1 Calculationofaweightforeachparsedword scoreisbasedonthenumberofwordscontainedinthe inthereferencefile responsephrasethatare"valid"(ie.present)inthe referencefile,thenumberofwordsinthereferencefile wordTchoentsayisnteedmincatlhceurleafteerseancweefiilgeh.tThfiosrweeaicghhtpagrisveeds pphhrraassee,s.anTdhethfeowremiuglhatuosfetdheiswaosrfdosllcoowms:montothetwo a—sinntighnladetinciaus,tmieiotrniiocnfdcitochdaeetp.eoswwehretohfedristchreimwionartdiocnaonfltehaedwtoorda P= (numbienrcoofmwomrodns)1 (Sweightisnocfowmomrodns) suchTahweahyeutrhiatstiitcdewceriegahstesofasthtehewnourmdbiesrcoonfsctorduecstewditihn (innuthmeberersopfonvsaelipdhrwaosred)s (renfuemrbeencreoffiwleoprhdrsasien) whichitisassociatedincreases.TheweightHofaword hasthefollowingform: Whenaresponsephrasematchesexactlyaphrase H fromthereferencefile,theformulabecomes: P=(numberofwordsincommon)*(Sweightsofwords incommon) where: 3.5.3 Evaluationofmatchesandselectionofa winner EM is•thtsehpeeecnuitnfriifocoptryomoiaftytshioenfgwaloerdidcs.otdrEeinb,utttrihooenp.yenWitshraeomnpeyaaiswsuonrriled;oiifst totheToforlelsoowlviengintdhirreeectpamraatmcehteesr,st:heuserassignsvalues reaches its maximum when the word is 1 MIN: lowerlimitofscore associatedwithallitems(thatisthencodes)in 2.MAX:upperlimitofscore theclassificationsystem. 3.PCNT:percentagedifference Pi istheproportionofoccurrencesofthewordinthe Letusassumethattherearempossiblematchesin filesforthei"1code;thisquantityisthereforea thereferencefile.Thescoresobtainedbythesephrases measureoftheprobabilitythatgiventheword, arearrangedindescendingorder: theappropriatecodeiscode/. P,>P2> ...>Pm flie1991CanadianCensusofPopulationExperiencewithAutomatedCoding. 189 Asa(rie)suIlft,Pf1o>u=rMsiAtXuaatinodns(mPa,y-aPri2)se/:P,>=P'CNT qscuyoesmstptelimeoatntenidaciqruseeastmtopilo2inn0nga%.iroeTfbhyethmeariedlws.eplolnidnegnst,froetlulronwsingthae thenthephrasethatobtainedscoreP,isthewinner The long questionnaire serves to collect anditsnumericcodeisassignedtotheresponse informationonthecharacteristicsofindividuals.The phrase. shortquestionnaireisanabridgedversionofthelong (tcihoie)nnsIifdalePlr,ep>dh=arsaMsbeAesiXnigasmnuudclht(Pi,pthl-aePtw2i)Pn/{nP>e,r=s<.PMCANXTare qhosueroxeut,ssetidninaoagtnnentaa-nioodrfceic;bnuidpriiittvhei,ddiudnlawcelelgsaul(ldleei.msngag.r,,ointrtleayyllpaetsboitaaofstndiuswcsh,eilpqclutoieonmsgPtm,eiooronnsw-sonlneaor1nw-, (iii)IfMIN<=P,<MAX statusandfirstlanguagelearned).Torespondtoa thenallphrasesisuchthatMIN<=Pj<MAXare qnuuemsbtieorn,ortwhreitreesipnoandreesnptomnsues.tmarkacircle,writea consideredaspossiblematches. Somewrite-inresponsesarecodedmanuallyin (iv)IfP,<MlN preparationfordatacapture.Alltheinformationon thennomatchqualifies. short and long questionnaires,exceptfor write-in responses already coded, is captured in a single Allresponsephrasesinsituations(ii),(iii)or(iv), operationoverafour-monthperiod.Foreachvariable afpisrloewdemulcultsaitsonbt,ehocasleoldwesidutchmhannoruepaosltpleoynnt.sieaDluprmhiarntagcshetshienattvehaseitlsraepbfrleieroernacrteoe swotuehblejlrecaotscctauoupxaaiunlttisoarmoyaftvteahdreicadobwdleeilsnlgir,negltahatreienwgtrritatones-tfihenerrrpeeedsrtpsooonansdeaanatdsa studied inorderto improvethereferencefile,the basetofacilitatethecodingoperation. parsingrulesandthematchingevaluationparameters. The1991Censusautomatedcodingapplicationis 3.6 ACTRperformance iilnltuesgtrraatteedd.ItinencFiogmupraesse2.saTuhteomaatpepldiccoadtiionngbiysAhCiTghRl,y dtihreecrOtefwmeiartnecgnhciteonfgiitltseeuicsshevneoirfqytuheleasrcghoeim.gphrleysesfefidcipehntr,aseevekneyw,htehne tcenroewrmcooperusstts.yeaprre-Nysa.ossoifrsetcteouddrinmnagn,tuoaalntdhceordeicantcgit,fuiaqcluaatliqiotunyesoctfoinostnyrnsoaltieormfeattihices extraTcotsmfarkoemintdhierercetfmeartenccheinfgilmeoarlleetfhfeecpthirvae,seAsCtThaRt Figure2. Censuscodingapplicationmodules containthewordintheresponsephrasewiththehighest heuristicweightH,anddeterminestheirscores.Next, Responsephraseand thewordintheresponsephrasewiththesecondhighest auxiliaryvariables weightisidentifiedand,usingthisweight,a"maximum possible"scoreisestimated.Ifthisscoreislowerthan ACTR theMINparameter(thescoreforavalidmatch)the Directmatching processishalted.Otherwiseextractionofreferencefile 1 phrasesandcalculationoftheirscorescontinue. ACTR Qualitycontroltable Indirectmatching ACTRresults 4. 1991CENSUSCODINGAPPLICATION 1 1 4.1 General Computer-assisted Qualitycontrol manualcoding tablecoders'results TheCanadianCensusofPopulationandHousing usestwotypesofself-administeredquestionnairesto canvass more than 10 million dwellings. When Codingresults Rectificationof establishing the list of dwellings in his or her systematicerrors enumerationarea,acensusrepresentativedistributesa shortquestionnaireto80%ofthedwellingsandalong 190 AutomatedCoding The1 questionssubjectedtoautomatedcodingare minimumscoreMIN,noinformationfromACTR shown in Appendix B. Ofthese, 12 similar but forwarded. js customizedapplicationswereestablished. 4.2 ACTR-directmatching 4.4 ACTR-notesonexecution Onlytheresponsephrasewithoutitsauxiliary filesAanndumthbeersaomfeapppalircsaitnigonsstrsahtaergieedst.hTehseasmeefrileefserweenrcee prpviheahderrsrniapatassoibeenflssieeetsishnapituthshnreiiausqssreueepsedfaercrrfsoeeoerrnsdrcpeaeoasunfnptsidlooeenm.dmpaIihatfrntetagcdhshetecroesoe.dtdihiIswetniaguti.mshnaiTttqthhchuiehsee,suppaynhallsirrtqastesuehemdee ccrcsoaeoanunsmtssppateolirnednuseecetdtsoeebrffdioroturrohseamiEstnnpioggoonlnngeisoonseftihsrrnaie.gensfsudrhlootiFsunmr.secenlthcahoshelsdei^nf1tis9rcui8aret6vsieowynChseim.nacTsnhhuudaseildsfai,nlnoedtas receivethesamecodeandtheresultisenteredinthe qualitycontroltableforACTRresults. possiSbilnecteotahnealcyosdeinAgCaTppRlirceastuilotsnawnadsurnucnoddaeildy,phirtawsaess (qmwueretishttoFeido-or.inntsOhCewnalaCneysandstdiuhoasenn,ePtclhisaetoiclaeeesul,tyootfmobawRytneeswsdiaacdynoeddnoicfmneugtnh5oiifcsyi9epmoaaaflrtistcthhieaiegn1sog) Nawreueogtruoeilmamarpultrpye.oddavDtmeueamrdteicnnhftgiivonaefgfprtoaaiutrmreseimasnongdnitnstthhroeaprtqedeuregaiirloeidst,toywraoeisffnetcprhreeeenrarcmseeiestufltittlehsede.s aquuetsotmiaotnedalcsoodiunsgedmaitncdhiirencgtramtaet.chingtoincreaseits ubnefcoaruesseeetahbelei.mpactonthequalityoftheresultswas 4.3 ACTR-indirectmatching 4.5 Computer-assistedmanualcoding matcAhlilngunairqeutehepnhrsausbejsectthaetdatorethneotincdoidreecdtvmiaatcdihriencgt compuFtorerphsreaasrecshefsaitlhiengoaruigtionmaaltfeidlecoofdereasspsoingsnemepnhtr,astehes method.Informationconcerningthe"multiplewinners" (orderedalphabetically)andpreparesbatchesof200 aconrdr"epsopsosnidbilnegs"c(otdheeamnadtcthheedscroerfee)reinscfeofriwlearpdhreadsteo,tthhee ournicgoindaeldqpuhersatsieosn.naCiroed,erbsutdtohenoftolhlaovwiengacicnefsosrmtaotitohne corompifuttehre-raessairseteodnlmyanmuaatlcchoedsinwgi.thIftshceorreesisbneolmoawtcthhe, afiprpsteasrcsreoennttwhoesccordeeenrss(eseeseFthiegurpehsra3seantdo4)b.eOcondetdh,e Figure3. FIRST.SCREEN MANUALCODING-MAJORFIELDOFSTUDY RESPONSF.PHRASF Type Code RENAISSANCEARCHITECHTURE PhrasesprovidedbvACTR Codes Choice ARCHITECHTURE 267 ABROCAHTIATRECCHTIUTREECDH'TAURRTE 048 308 Dataofeachhouseholdmemberforthe'samequestion Checkboxes: Write-inphrases: PF1=Help PF9= Referral LMMllllli"'nn.nwiirmnim^^^^^auiUMIM\ttmmmvim.mnmwiM.m^um,mimvj.i^w