北大教授易君健論文：大城市女多男少竟是因為想“高嫁”？Young Women in Cities Urbanization and Gender-biased Migration

YoungWomeninCities:UrbanizationandGender-biasedMigration*YumiKohtJingLi?YifanWu§JunjianYi?HanzheZhangⅡAbstractYoungwomenoutnumberyoungmenincitiesinmanycountriesduringperiodsofeconomicgrowthandurbanization.Thisgenderimbalanceamongyoungurbanitesismorepronouncedinlargercities.WeusethegradualrolloutofSpecialEconomicZonesacrossChinaasaquasi-experimenttoestablishthecausalimpactofurban-izationongender-di?erentiatedincentivestomigrate.Wehighlighttheroleofthemarriagemarketinincreasingruralwomen’schanceofmarryingandmarryingupinurbanareasduringrapidurbanization.Keywords:urbanization,migration,genderimbalance,marriagemarketJELclassi?cations:O15,J12*WethankKristianBehrens,JanetCurrie,JorgeDelaRoca,CesarGarro-Marin,ScottHegerty,ZhiWang,BenZou,andtheaudienceatvariousseminarsandconferences.Kohacknowledgesthe2023ResearchFundoftheUniversityofSeoul.ZhangacknowledgestheNationalScienceFoundationandMichiganStateUniversityAsianStudiesCenterDelioKooEndowmentFund.tSchoolofEconomics,UniversityofSeoul.E-mailaddress:ymkoh@uos.ac.kr?SchoolofEconomics,SingaporeManagementUniversity.E-mailaddress:lijing@.sg§StrategicDevelopmentDepartment,ShanghaiTrust.E-mailaddress:wuyf@?ChinaCenterofEconomicResearch,NationalSchoolofDevelopment;InstituteforGlobalHealthandDevel-opment,PekingUniversity.E-mailaddress:junjian.yi@ⅡDepartmentofEconomics,MichiganStateUniversity.E-mailaddress:hanzhe@11IntroductionWomenoutnumbermeninurbanareasinmostcountries(WorldBank2023).1Figure1depictsthenetfemaleshare(femaleminusmaleshare)byageforlocalsandinternalmigrants,basedontheChinesePopulationCensus2000.Asthe?gureshows,thenetfemaleshareisclosetozeroacrossallagesforlocals,suggestingabalancedgenderdistributionamongthem.Incontrast,thenetfemaleshareispositiveforyoungmigrants,suggestinganexcessofyoungfemalemigrants.Overall,itshowsthatthisgenderimbalanceislargelyin?uencedbymigration,ratherthanbyfactorspresentatbirth.Moreover,thisgenderimbalanceismorepronouncedinlargercities.Figure2showsthatyoungfemalemigrantsarepredominantlymovingtolargercities.Figures2aand2bshowthatthesurplusofyoungfemalesamongmigrantsismoreprominentindestinationswithalargersize,measuredbypopulationsizeasreportedintheChinesePopulationCensus1982.Consequently,theoverallgenderimbalanceamongyoungindividualstendstoincreasewithcitysize(Figure2c).Thistrendpersistsevenwhenaccountingforheterogeneityinindustrialcompositionacrosscitiesbycontrollingforindustry?xede?ects(Figure2d).Inthispaper,weaimto(i)identifygender-di?erentiatedmigrationpatternsamongyoungcohortswithinadevelopingcountryduringperiodsofrapidurbanizationand(ii)investigatevariousmigrationincentivesthatmaycontributetogender-speci?cmigrationpatterns.OurempiricalanalysiscentersoninternalmigrationinChinabetween1996and2000.Thisprovidesanidealsettingbecauseitwasatimemarkedbyrapidurbanization,activeinternalmigration,andagrowinggenderimbalanceacrossregions.Althoughouranalysisisgroundedinthespeci?ccontextofChina,theimplicationsdiscussedlaterarebroadlyapplicabletootherdevelopingcountriesthatexperiencesimilarrapidurbanization.Tocausallyidentifytheimpactofurbanizationongender-di?erentiatedmigrationincentives,weexploitthegradualrolloutofSpecialEconomicZones(hereinafterSEZs)acrossChina.The1Urbanareasinmanycountriesexhibitanotablesurplusofyoungwomen,suchasallCentralandSouthAmericancountries(Tacoli2012);GermanyandRussia(Wiestetal.2013);India(PTI2017);Scandinaviancountries(Pettayetal.2021);Vietnam(Nguyen2022);andChina,aswewilldocumentinthispaper.2SEZscreatelocation-time-speci?cvariationsintheextentofurbanization,in?uencingeconomicattractivenessacrossdi?erentlocationsandconsequentlyimpactingindividuals’migrationde-cisions.Ouridenti?cationleveragesthenumerousSEZsestablishedacrossChinainasporadicmannerduringoursampleperiodandthequasi-randomestablishmenttimingdrivenbythebu-reaucraticprocess.Thesefeaturesareparticularlyimportantbecauseidentifyingthecausallinkbetweenurbanizationandmigrationissubjecttoendogeneityconcerns:Thebirthandgrowthofacitydependonacomprehensivesetoflocation-speci?cfactorssuchasculture,geography,transportation,naturalresources,climate,andhistory(Mumford1961),whichareoftendi?culttoobserveandmeasure.Totheextentthatthesefactorscorrelatewithgender-di?erentiatedpreferencesforlivinginurbanareas,itcouldgiverisetoanendogeneityproblem.OurempiricalstrategythatexploitstherolloutofSEZshelpsaddresssuchendogeneityconcerns.Weusetwosetsofdata:(i)theChinesePopulationCensus2000and(ii)thelistofSEZspublishedbyNationalDevelopmentandReformCommissionofChina.Byaligningthemigra-tiontimingofindividualsinthecensuswiththeestablishmenttimingofSEZs,weestimatetheimpactofSEZopeningsonmigrationvolumesandthegenderratioamongmigrantsforeachyearduringoursample.Ourestimatesfromthestaggereddi?erence-in-di?erences(hereinafterDiD)modelatthecountylevelrevealthattheopeningofanSEZincreasesthein?owofyoungmigrants,withaparticularlynotablee?ectontheratioofyoungfemalemigrants.Tofurtheraccountforindividualheterogeneity,weemploya?rst-di?erence(hereinafterFD)estimatorattheindividuallevel.WeconstructaBartik-likecompositeexplanatoryvariablethatcapturesthechangesintheexternalattractionforceinotherlocationsbetween1996and2000.Thisvariableactsasa“pullforce”thatmotivatespeopletorelocatewhenotherlocationstreatedwithSEZopeningsbecomemoreattractiveduetoincreasedopportunitiesfromurbanization.Itsimpactisweightedbythepre-existingmigrationnetworkin1995.We?ndthatonestandarddeviationincreaseintheconstructedpullfactorleadstoa1.90percentagepointincreaseintheprobabilityofemigratingtoothercountiesforyoungmales.Thee?ectis0.19percentagepointslargerforyoungfemales.Theseestimatesnotonlyexhibitstatisticaldi?erencesbetweenmales3andfemalesbutalsodemonstrateasubstantialmagnitudeofdi?erence,particularlynotableconsideringthatapproximately10%ofthepopulationmigratedduringoursampleperiod.Theseresultsremainrobustevenafteraddressingpotentialbiasesthatarisefromtheendogeneityofthepre-existingmigrationnetworkinconstructingthepullfactor,usingthemethodproposedbyBorusyakandHull(2023).Tofurtherinvestigatepotentialmechanismsdrivinggender-di?erentiatedmigrationamongyoungindividuals,weinvestigatemaritalandnonmaritalincentivestomigrate.Onthemari-talfront,giventhepatrilocalityandhypergamycontextinChina,moreruralwomenmaybeattractedtomigrateinsearchofmorecompetentandwealthierhusbands.Onthenonmari-talaspect,betterlabormarketopportunities,educationalopportunities,andincreasedbene?tsfromamenitiesmayalsoattractwomen.OurestimatesfromtheFDmodel,basedonvarioussubsamplesandadditionalmaritalmarketoutcomes,alignwithexplanationscenteredonmar-italincentives.We?ndthatastrongerpullforcenotonlyincreasesthelikelihoodofmarriagebutalsothelikelihoodofmarryingupforyoungfemales,incomparisontotheiryoungmalecounterparts.Falsi?cationtestsinvolvingtwosubsamples—olderindividualswhowerealreadymarriedbeforeoursampleperiodandyoungerindividualswhowerealreadymarried—supportourclaims.Thesetestsshowthatthesefemalesexhibitastatisticallyandeconomicallysignif-icantlylowermagnitudeofemigrationinresponsetoalargerpullfactor.Moreover,anotherfalsi?cationtestusinganethnicminoritygroupwithahightendencyforendogamousmarriageshowsthatfemalesarenotmoreresponsivetothepullfactor.Thisevidenceisagaininlinewiththemarriagemarketmechanismsincelargeurbanareasdonotnecessarilydisproportion-atelyattractfemalesinthisminoritygroupformaritalreasonsand,hence,thegenderdi?erenceinmigrationincentivesismuchreduced.Asfornonmaritalincentives,weexplorealternativepotentialmechanismsrelatedtotheindustrialshiftsinthelabormarket,educationalopportuni-ties,andamenities.Whilethesenonmaritalfactorsmaypartiallyaccountforourobservations,theydonotseemtoprovideacompleteexplanationforour?ndings.Ourstudycarriesweightforbothscholarsandpolicymakers.Thedisparitiesthataccompany4rapidurbanizationarenotablebetweenurbanandruralareasandbetweenmalesandfemales.Fromtheperspectiveofthemarriagemarket,thepresenceofrelativelymoreyoungfemalesinurbanareasbene?tsmalesanddisadvantagesfemalesincities;thereverseistrueinruralareas.Oneimplicationofourstudyisthatsuchwideningspatialinequalityandgenderdividemayhavefar-reachingsocialimplicationsonmarriageandbirthoutcomes.Spatialmismatchingendermayfurthercauseadeclineinoverallsocialandfamilystability.Anotherimplicationofourstudyisthatthegenderimbalanceinmigrationdrivenbymaritalincentivescanfurtherhaveareciprocale?ectonthelabormarket.Speci?cally,thepresenceofmorewomeninurbanareascanpotentiallya?ectthetypesofjobsavailable,competitionforjobsearch,andthegenderwagegapincities.Thisstudycontributestotwostrandsofliterature.First,itaddstotheliteratureongenderdi?erencesinurbanization.StartingfromMarshall(1890),researchershavedocumentedcities’advantagesinhigherproductivity,higherwages,andbetteramenities,whichprovideincentivestomigrateandsettle(RosenthalandStrange2004;CombesandGobillon2015;Diamond2016;CoutureandHandbury2017;FanandZou2021).Afewstudieshighlightgenderdi?erencesinresponsetosuchurbanadvantages,leadingtovariationsbetweenurbanandruralareasintermsofgendergapsinlaborparticipation,wages,andentrepreneurship(Phimister2005;RosenthalandStrange2012;Bacolod2017).Inthispaper,weconcludethatthegenderdi?erenceinmigrationincentivesofruralyouthsisalsolikelydrivenbygender-di?erentiatedreturnsfromthemarriagemarketincities—animportantperspectivethathasnotbeenfullystudiedintheliterature.Second,thispapercontributestotheliteratureongenderdi?erencesinpremaritalinvest-mentandconsequentmarriageandlabormarketoutcomes.Previousstudiesmainlyfocusonpremaritalinvestmentintheformofwealth,education,ortheirinteractions(Zhang1994;PetersandSiow2002;Chiapporietal.2009;Zhang2021;Bhaskaretal.2023;ZhangandZou2023).SimilartoDupuy(2021)andAhnetal.(2023),ourpaperconsidersmigrationaspremaritalinvestment.Incontrasttostudiesthatmostlysuggestthetheoreticalimportanceofpremarital5investments,weemploycarefullydesignedempiricalmethodstocausallyidentifytheirimpor-tance.Ourresearchthuscontributestotheclassicquestionofwhomarrieswhom,asexploredbyChooandSiow(2006)andChoo(2015),withaspeci?cfocusonthecontextofeconomicdevelopment,urbanization,andmigration.Therestofthepaperisorganizedasfollows.Section2detailstheinstitutionalbackground.Section3describesthedata.Section4laysouttheempiricaldesign.Section5reportsempiricalresults.Section6discussespotentialmechanisms,andSection7concludes.Theremainingproofsandresultscanbefoundintheappendices.2InstitutionalBackground2.1SEZsinChinaChina’sSEZswere?rstestablishedinthelate1970saspartofChina’seconomicreformandopening-uppolicy(Shirketal.1993).The?rstSEZwasestablishedinShenzhenin1979,andwasfollowedbySEZsinZhuhai,Shantou,andXiamenin1980.ThesefourcitieswerechosenbecauseoftheirproximitytoHongKongandTaiwan,andwereintendedtoserveaspilotprojectsforChina’seconomicreforms(Xu2011).SEZsweredesignedtoattractforeigninvestmentsandpromoteexports.Thesezoneswereequippedwithspecialeconomicpoliciesandincentivesthataimedtofacilitateeconomicgrowth(Alderetal.2016).2TheeconomicperformanceofthefourinitialSEZswasremarkable.Forexample,between1980and1990,Shenzhen’sgrossdomesticproductgrewatanaveragerateofapproximately28%peryear(NationalBureauofStatisticsofChina2021).ThesuccessofthefourinitialSEZsledtotheirproliferationinotherregions.Inthe1990s,thecentralgovernmentembracedSEZdevelopmentasanationalstrategy,withtheintentionof2Suchincentivesincludedpreferentialtaxpoliciesthatlowerorexemptcorporatetaxes;simpli?edcustomsprocedurestofacilitatetrade;reducedbureaucraticproceduresthateasebusinessoperations;preferentiallanduse,suchaslowerland-usefeesandpriorityaccesstoland;accesstocreditandother?nancialresources;andopennesstoforeigninvestmentbyallowingforeigninvestorstoowntheirentireenterpriseswithouttheneedforaChinesepartner.6achievinggeographicdiversity.ThenumberandareaofSEZsincreasedsigni?cantlyinthe1990s(seeFigureC.1intheappendixfortheannualnumberofSEZsestablishedandthecumulativeareaofSEZsfrom1984to2000).Morespeci?cally,106SEZswereestablishednationwideduringthe1996-2000timeframe.3Figure3illustratesthetemporalgeographicexpansionofSEZswithfourpanelsrepresentingdi?erentyears(1990,1995,2000,and2005).Between1995and2005,SEZswereestablishedacrossChinainadispersedmannerandplayedasigni?cantroleinpromotingurbanizationinChina.4TheestablishmentofSEZswastypicallyaccompaniedbyaformalannouncementfromthecentralgovernment,whichincludedacomprehensivepackageofpoliciesandincentivesdesignedtoattractforeigndirectinvestment(hereinafterFDI).Thesepolicieswereimplementedimme-diatelyaftertheannouncement.Beforeanareawaso?ciallydesignatedasanSEZ,investmentsmadebylocalgovernmentsinpreparationforthistransitionwereminimalduetothelimiteddomesticinvestmentcapabilitiesatthatstageofChina’seconomicdevelopment.Signi?cantinvestmentsininfrastructure,suchasroads,construction,andbuildings,weremadeaftertheSEZstatuswaso?ciallyannounced.Theselarge-scaleinvestmentswerecrucialforcreatinganenvironmentconducivetoattractingFDIandsupportingrapideconomicdevelopment(Xu2011).Ouridenti?cationstrategyreliesonthequasi-randomvariationinthetimingofSEZestab-lishmentbetween1996and2005,giventheirselection,asoutlinedindetailinSection4.Inthe1980s,SEZswereprimarilylocatedinChina’seasterncoastalregionsattheinitialstagesofeco-nomicreform.TheestablishmentandsuccessoftheseSEZshavecontributedtotheprosperity3Whenwemapthese106SEZstocounties,weidentify86countiesthatareincludedintheChinesePopulationCensus2000.Thus,thenumberofcountiestreatedwithSEZsduringoursampleperiodintheanalysisbecomes86.4UnliketheareastreatedwithSEZsintheinitialstageduringthe1970sand1980s,theareastreatedwithSEZsfrom1996to2000thatwestudyinthispaperweremuchmoreruralandlocatedinlessdevelopedregions.Forinstance,Wang(2013)categorizesSEZsintodistinctgroupsbasedontheirestablishmentyears,allowingforcomparisonsoftheirmunicipalcharacteristicsfrom1978.WhiletheearliestSEZsestablishedbetween1978and1985hadapercapitaindustrialoutputof622RMBin1982,thoseestablishedbetween1996and2008hadapercapitaindustrialoutputof280RMBinthesameyear.NotethatareaswithoutSEZshadapercapitaindustrialoutputof271RMBin1982.Therefore,theregionstreatedwithSEZsduringoursampleperiodwerepredominantlylessurbanizedareaswithlowerindustrialoutputpriortobeingtreatedwithSEZs.7ofthecoastalregionsbutalsoexacerbatedeconomicdisparitiesbetweendi?erentregions.Con-sequently,e?ortsweremadeinthe1990stoestablishSEZsinamorebalancedmanneracrossthecountrytoreduceregionaldisparities.Especiallysince1995,theSEZswerescatteredacrossthecountryalmostevenly(Swertsetal.2021).Forexample,SEZsestablishedbetween1996and2005shareverysimilarlongitudes.Duringthisstage,thetimeoftheirestablishmentcanbeconsideredquasi-randomasitvariedprimarilyduetothebureaucraticprocessesinvolvedinapprovingtheSEZs(Craneetal.2018).2.2TheHukouSystemandInternalMigrationinChinaBeforetheeconomicreformin1979,migrationwithinChinawasrareunderthehukousys-tem,whichhasbeeninplacesincethe1950s(Young2013).Thesystemisbasedonhouseholdregistration,whichassignseveryChinesecitizenaplaceoforiginrecordedontheirhukouorhouseholdregistrationdocument.Thehukousystemdividesthepopulationintotwocategories:ruralandurban.Arural(resp.,anurban)hukouisassignedtoindividualswhowerebornandraisedinthecountrysideorsmallertowns(resp.,incities).Thehukousystemservesvariouspurposes,includingdeterminingaccesstopublicservicessuchaseducationandhealthcareandtrackingpopulationmovement.Thesystemrestrictsaccesstopublicservicesandjobopportu-nitiesbasedonanindividual’splaceoforigin,makingitdi?cultforpeopletomovefromruraltourbanareasandreceivethesamelevelofservicesastheywouldintheirplaceoforigin.China’seconomicreformin1979broughtsigni?cantchangestothehukousystem.WiththeestablishmentofSEZsandthetransitiontoamarket-orientedeconomy,therewasgrowingdemandforlaborinurbanareas,andmanyruralresidentsbegantomigratetocitiesinsearchofwork.However,thehukousystemremainedasigni?cantbarriertomigrationandmobilitysinceruralresidentswerenotallowedtoobtainanurbanhukou;thisrestrictedtheiraccesstosocialwelfarebene?tsandpublicservices.Toaddressthisissue,thegovernmentbegantoimplementreformstothehukousysteminthe1980s.Onekeychangewastheintroductionofatemporaryresidencesystem,whichallowedruralresidentstoobtaintemporaryurbanresidencepermits.8Thesepermitsgrantedthemaccesstolimitedsocialwelfarebene?tsandpublicservicesinurbanareas,althoughtheywerenotequivalenttoanurbanhukou.Inthe1990s,thegovernmentintroducedfurtherreformstothehukousystemtopromotegreatersocialinclusionandmobility.Oneofthesigni?cantchangeswastheintroductionofthe“?oatingpopulation”concept,whichformallyrecognizedtheexistenceofmigrantworkersandgrantedthemcertainlegalrightsandprotections.Forexample,thegovernmentstartedbuild-ingprimaryandsecondaryschoolsspeci?callyforchildrenofthe?oatingpopulation.However,despitethesereforms,ruralmigrantsstillfacedsigni?cantdisparitiescomparedtourbanresi-dents.Whilethegovernmenthasextendedsomesocialwelfarebene?tsandpublicservicestononlocalmigrants,thesewereoftenlimitedandnotonparwiththoseavailabletourbanhukouholders.Forinstance,ruralmigrantstypicallyhadrestrictedaccesstohigh-qualityeducationandhealthcareinurbanareas.Therelaxationofthehukousystem,coupledwithChina’seconomicgrowth,ledtoanun-precedentedwaveofinternalmigrationinthe1990sand2000s.Theurbanpopulationshareincreasedfrom19.39%in1980to26.22%in2000(NationalBureauofStatisticsofChina2021).BasedonourcalculationsusingtheChinesePopulationCensus2000,thetotalnumberofcross-countymigrantsagedbetween16and25grewabout13-foldfrom1995to2000(seeFigureC.2intheappendix).AccordingtothepopulationcensusconductedbytheNationalBureauofStatis-tics,thenumberofmigrantswasestimatedtobe376millionin2020.Withtherelaxationofthehukousystem,rapidurbanization,andactiveinternalmigration,thisprovidesanimportantempiricalcontextforstudyinghowurbanizationa?ectsgender-speci?cmigrationpatterns.2.3HypergamyandPatrilocalPracticesinChinaTwoenduringmaritaltraditions—statushypergamyandpatrilocalpractices—continuetoprevailinChina.Aswewillelaborateinoursubsequentanalysis,understandingthesepracticesiscrucial,astheyplayapivotalroleingeneratingasymmetriesbetweenmalesandfemalesinmigrationandmaritaldecisions.9Statushypergamydescribesthetendencyofawomantoformarelationshipwithamanofhighersocial,economic,oreducationalstatusandiscommonacrossvariousregionsandcultures.Althoughhypergamyhasenduredasalong-standingtraditioninChina,ithasbeenfurtherfueledbytheincreasingeconomicpressuresresultingfromreforms.5Asoldermentendtopossessgreatereconomicresourcescomparedtoyoungermen,oneindicatorofhypergamycanbeobservedbyexaminingtheagedi?erencesbetweencouples.Analyzingmarriedcouplesunder55fromtheChinesePopulationCensus2000,we?ndthat26.72%ofmigrantfemalesaremarriedtomenfourormoreyearsolder,comparedto21.25%ofnon-migrantfemales(seeTableD.1intheappendixfordetails).Educationlevelservesasanotherproxyformen’shigherstatus,andweexaminemarriagematchingpatternsinTable1,whereeducationlevelsarecategorizedinto?vegroupsforbothhusbandsandwives.Level1(level5)representsthelowest(highest)levelofeducation.Whitecellsindicatemarriageswithwiveshavinghighereducation,thelight-greydiagonalcellsdenoteequaleducationlevels,anddark-greycellsindicatemarriageswherehusbandshavehigheredu-cation.Ninety-onepercentofcouplesinvolvehusbandswhoareequallyormoreeducatedthantheirwives.AnotherimportantmarriagetraditioninChinaisthepatrilocalpractice,whichreferstoaresidencepatterninwhichamarriedcoupleliveswithornearthehusband’sfamilyorthehusband’srelatives.6Itspracticeisstillresilient.Ouranalysisusingthe2010ChinaFamilyPanelStudiesshowsthat,forcoupleswithpartnersbornindi?erentcities,78.1%liveinthehusband’scityaftermarriage,and20.5%liveinthewife’scity.Theshareismoreunbalancedifoneofthespouseswasborninaruralarea:amongthosecouples,92.8%liveinthehusband’sbirthcity,andmerely5.6%liveinthewife’sbirthcity.5Morespeci?cally,“intensi?edlabormarketpressure,risingconsumerism,andskyrocketingcostsoflivingactedtopromotemarriagesofoldermentoyoungerwomenonthebasisofaneedorpreferenceforstatushypergamy”(MuandXie2014,p.151).6Patrilocalityis“acoreaspectofthetraditionalChinesekinshipsystemandisdeeplyrootedinConfucianism”(GruijtersandErmisch2019,p.562).3DataOurempiricalanalysisprimarilyreliesontwodatasets.The?rstistheChinesePopulationCensus2000.Fromthesample,weuseinformationonvariousdemographicandmigration-relatedvariablesfromeachsurveyedindividual:gender,yearofbirth,educationlevel,maritalstatus,marriageyear,migrationstatus,migrationyear,countyofresidence,aswellasthecountyoforiginanddestinationforthosewhomigrated.Wefocusonthe2000censussampleforthreereasons.First,itcontainsoneofthelargestsamples—1%ofthepopulation—comparedwithcensussamplesavailableforanalysisinlateryears.Second,itprovidesinformationonboththeoriginandthedestinationofamigrant,whichisanadvantageoverthecensusdatacollectedinearlieryears.Third,itallowsustoaccuratelyidentifythemigrationyearstartingfrom1995.7Forthisreason,ourfocusisonthechangesthattookplacebetween1995and2000orbetween1996and2000.8Thespeci?ctimeframedependsonwhetherweneedtoexcludetheinitialyear,1995,tousepredeterminedconditions.Fourth,duringthesampleperiod,hukourestrictionsonmigrationweresigni?cantlyrelaxedcomparedwithearlieryears,whichallowsustoobservealargesampleofmigrants.Last,thecountryhasnotyetbeena?ectedbyitsWTOaccessionin2001.TheseconddatasetisthelistofSEZspublishedbytheNationalDevelopmentandReformCommissionofChina.9ThelistprovidesinformationontheSEZID,name,approvaldate,approvalauthority,andtargetedindustriesforeachSEZ.ToidentifycountiesthatweretreatedwithSEZs,wetrackthegeographicboundariesofeachSEZestablishedduringoursampleperiodandmatchthemwiththecorrespondingcounties.7Thecensusaskedrespondentswhethertheyhadalwayslivedintheirbirthtown.Ifnot,theywereaskedtoprovidethedestinationcountyandtheyearoftheirlastmove.Duetothequestionnairedesign,allyearsbefore1995weregroupedas“movedbefore1995,”sowecanonlydeterminetheexactmovingyearstartingfrom1995.8Duetothesurveyquestionnairedesign,whichasksaboutthelastmove,wecaptureonlythemostrecentmovewithouttrackingmultiplemovesthatcouldhaveoccurredbetween1995and2000.However,giventherelativelyshorttimespan,thenumberofpeoplemigratingmultipletimesinourcontextislikelytobequiterare.Forexample,Bernardetal.(2019)?ndthattheaverageageat?rstmigrationforthecohortbornbetween1970and1974inChinais25.2formalesand23.3forfemales.Therefore,multiplemovesarelesslikelytoa?ectour?ndings.9Thelistwas?rstpublishedin2006(NDRC2006)andlaterupdatedin2018(NDRC2018).Toensurethatweusethefullinformation,wecombinebothlistsandtrackSEZestablishmentsduringoursampleperiod.Weconstructourdataattwolevels.First,atthecounty-yearlevel,wetrackthechangesinmigrationsizeandSEZtreatmentstatusforeachcountyacrosseachyearfrom1995to2000.Throughoutthispaper,wede?neindividualsasmigrantsiftheymoveacrosscounties.Wefocusoncross-countymigrantsbecausewetrackSEZshocksatthecountylevel.Inpanel(a)ofTable2,wepresentthesummarystatisticsondemographicsin