Measuring Migration: Measuring Migration: Best Practices in Censuses Best Practices in Censuses

and Household Surveysand Household Surveys

Gero CarlettoGero Carletto

Carlo AzzarriCarlo Azzarri

BackgroundBackground Migration policy research hampered Migration policy research hampered

by availability of databy availability of data Definitions and measurements of Definitions and measurements of

migration varies migration varies acrossacross and and withinwithin countries (from ≠ sources), and countries (from ≠ sources), and overtimeovertime

Best practices?Best practices?• Lack of consensusLack of consensus• Who is an international migrant?Who is an international migrant?• What type of migration?What type of migration?

What type of migration?What type of migration?

Flow vs. StockFlow vs. Stock Immigrant vs emigrant (net migration)Immigrant vs emigrant (net migration) Permanent/L-T vs. temporary/S-TPermanent/L-T vs. temporary/S-T Circular, returneesCircular, returnees InternalInternal Undocumented/irregularUndocumented/irregular International migrants vs. international International migrants vs. international

migration (multiple moves)migration (multiple moves)

Different definitions/dimensions, different Different definitions/dimensions, different sourcessources

OutlineOutline

Concepts and definitionsConcepts and definitions Data sourcesData sources Sampling and survey optionsSampling and survey options Questionnaire contents/designQuestionnaire contents/design Conclusions and next stepsConclusions and next steps

ConceptsConcepts (Change in) Place of usual residence(Change in) Place of usual residence Time/duration of stayTime/duration of stay Purpose of stayPurpose of stay CitizenshipCitizenship Place of birthPlace of birth

Alone or in combinations …Alone or in combinations …• in which order?in which order?• for which purpose?for which purpose?

Used differently by different sources and Used differently by different sources and depending on objectivedepending on objective

Definition of Int’l Mig (FLOW)Definition of Int’l Mig (FLOW) An An international migrantinternational migrant is a is a

person who changes his/her own person who changes his/her own country of country of usual residence usual residence (UN RSIM, (UN RSIM, Rev. 1)Rev. 1)• Place of usual residence?Place of usual residence?

“… “… normally spends daily period of rest”normally spends daily period of rest” Usual ≠ legalUsual ≠ legal Boarding students? “Weekly commuters”?Boarding students? “Weekly commuters”?

• No provision for …No provision for … Duration of stayDuration of stay Purpose of movePurpose of move

Long- vs. Short-term migrants Long- vs. Short-term migrants (UN RSIM Rev 1.)(UN RSIM Rev 1.)

A A long-term migrantlong-term migrant is a person who is a person who moves to a country other than that of moves to a country other than that of his/her usual residence his/her usual residence for a period of at for a period of at least a year (12 months)least a year (12 months)

A A short-term migrantshort-term migrant is a person who is a person who moves to a country other than that of moves to a country other than that of his/her usual residence his/her usual residence for a period of at for a period of at least 3 months but less than a year (12 least 3 months but less than a year (12 months)months) (except for recreation, holiday, (except for recreation, holiday, business, medical treatment, …)business, medical treatment, …)

Definition of Int’l mig.(STOCK)Definition of Int’l mig.(STOCK) ““Persons who have ever changed Persons who have ever changed

their country of usual residence i.e. their country of usual residence i.e. spent at least 1 year in a country spent at least 1 year in a country other than the one in which they live other than the one in which they live at the time data gathered” (UN RSIM at the time data gathered” (UN RSIM Rev. 1)Rev. 1)

Relevant population groups:Relevant population groups:• foreigners foreigners (non-citizens of country of usual (non-citizens of country of usual

residence)residence)• foreign-born foreign-born (born in country other than one (born in country other than one

in which they are being enumerated)in which they are being enumerated)• provisions for 14 special groupsprovisions for 14 special groups

Alternative definition Alternative definition (Bilsborrow et al, 1997)(Bilsborrow et al, 1997)

““An international migrant is a person who An international migrant is a person who have livedhave lived for at least for at least 6 months6 months in a in a country country other thanother than that in which they are that in which they are being interviewed and whose move into being interviewed and whose move into the country of interview occurred during the country of interview occurred during the the 5 years5 years preceding the interview” preceding the interview”

… … but definition assumes presence!but definition assumes presence!

Complementary definition Complementary definition (Bilsborrow et al., 1997)(Bilsborrow et al., 1997)

““An international migrant is a person who An international migrant is a person who

used to liveused to live in the country in which the in the country in which the interview is being conducted and was a interview is being conducted and was a member of the householdmember of the household of the person of the person being interviewed but who left at some being interviewed but who left at some point in time during the point in time during the 5 years5 years preceding preceding the interview to live abroad for at least the interview to live abroad for at least 6 6 monthsmonths””

Operationalizing definitionsOperationalizing definitions

Usual Place of residenceUsual Place of residence Some countries do not use concept of Some countries do not use concept of

“migrant”“migrant” Why 3-6-12 months?Why 3-6-12 months? Intended vs. actual duration of stay?Intended vs. actual duration of stay?

at time of arrival based on intentionat time of arrival based on intention upon completion of 12-month periodupon completion of 12-month period

Lots of provisions!Lots of provisions!

Data sourcesData sources

Population registersPopulation registers Other administrative recordsOther administrative records Population censusesPopulation censuses SurveysSurveys

Data sources: Pop RegistersData sources: Pop Registers PROS PROS

• ContinuousContinuous• Measure of FLOWS (consistent with STOCKS)Measure of FLOWS (consistent with STOCKS)• De factoDe facto duration of stay/absence (if centralized) duration of stay/absence (if centralized)

CONSCONS• Not run by NSO; coordinationNot run by NSO; coordination• Only limited informationOnly limited information• Often not public accessOften not public access• Often only nationals; only documentedOften only nationals; only documented• (dis)Incentive to register/deregister(dis)Incentive to register/deregister• IntendedIntended vs. actual duration of stay vs. actual duration of stay• Quality variability (if decentralized) Quality variability (if decentralized) • Feasible for LDCs? (EU from PopCensus to Registers)Feasible for LDCs? (EU from PopCensus to Registers)

Only 15 countries reporting flows figures (mostly Only 15 countries reporting flows figures (mostly from pop registers; UK, NZ from border statistics)from pop registers; UK, NZ from border statistics)

Data sources: Other admin recordsData sources: Other admin records

Border crossings (flows)Border crossings (flows) Registry of foreign workersRegistry of foreign workers Embassy/consular dataEmbassy/consular data Resident permit holders/applicantsResident permit holders/applicants Diaspora organizations/NGOs in D countryDiaspora organizations/NGOs in D country Emigration clearance certificatesEmigration clearance certificates Destination country sourcesDestination country sources

… … often incomplete both in coverage and often incomplete both in coverage and contentcontent

Data sources: PopCensusData sources: PopCensus Most reliable source of internationally Most reliable source of internationally

comparable IMMIGRANT comparable IMMIGRANT stocksstocks. .

PROS PROS • Universal coverageUniversal coverage• Some characterization possible, based on basic Some characterization possible, based on basic

demographics and socio-economic, e.g.:demographics and socio-economic, e.g.: Gender (feminization of migration)Gender (feminization of migration) Age (SSS; fertility)Age (SSS; fertility) Occupation (workforce)Occupation (workforce) Educational level (brain drain/gain)Educational level (brain drain/gain)

Data sources: PopCensus Data sources: PopCensus (cont’d)(cont’d)

CONSCONS• Every 10 yearsEvery 10 years• Limited information (policy analysis?)Limited information (policy analysis?)• Poor/delayed tabulationPoor/delayed tabulation• Low training of enumerators/data qualityLow training of enumerators/data quality• Different approaches/definitionDifferent approaches/definition

De factoDe facto (present population) vs. (present population) vs. de jurede jure (usual (usual population)population)

14 sub-groups for special treatment14 sub-groups for special treatment• Under-coverageUnder-coverage

Entire families that movedEntire families that moved Seasonal/temporary, circular (night prior to census Seasonal/temporary, circular (night prior to census

date)date) Marginal groups (undocumented migrants?)Marginal groups (undocumented migrants?)

• Housing arrangements, language, distrust, mobility, …Housing arrangements, language, distrust, mobility, …

Data sources: PopCensus Data sources: PopCensus (cont’d)(cont’d)

0 50 100 150 200 250

Oceania

Europe

Asia

America, South

America, North

Africa

Total

Number of countries

Having census data

Having data on migrantstock

(Chen, 2006)(Chen, 2006)

Data sources: PopCensus Data sources: PopCensus (cont’d)(cont’d)

Only 1 country in 89 compliant with UN Only 1 country in 89 compliant with UN RSIM Rev.1 (of 153; of 196)!RSIM Rev.1 (of 153; of 196)!

11 countries “close” to definition11 countries “close” to definition citizenship (93 countries)citizenship (93 countries)

• statelessstateless place of birth (112 countries)place of birth (112 countries)

• new countriesnew countries PoR at some point in time in the past (88 PoR at some point in time in the past (88

countries)countries)

(Chen, 2006)(Chen, 2006)

Data sources: PopCensus – emigrants?Data sources: PopCensus – emigrants? Self-reporting about “absentees”: based on socio-Self-reporting about “absentees”: based on socio-

econ status (hh membership)econ status (hh membership) Two (indirect) methods based on demographics Two (indirect) methods based on demographics

(IUSSP)(IUSSP)• Place of Residence (PoR) of siblingsPlace of Residence (PoR) of siblings• PoR of children (complementing existing sources; split PoR of children (complementing existing sources; split

surviving children by PoR)surviving children by PoR) Even more limited information on emigrantsEven more limited information on emigrants

• Less “flexibility”Less “flexibility”• No sensitive info (affect coverage)No sensitive info (affect coverage)• Feasible at all?Feasible at all?

Quality of informationQuality of information• Proxy respondentProxy respondent• Enumerator’s trainingEnumerator’s training

Balance equation/residual (Albania)Balance equation/residual (Albania) Using data from PopCensus in D countries?Using data from PopCensus in D countries?

Data sources: SurveysData sources: Surveys Despite “hype”, haphazard effortsDespite “hype”, haphazard efforts Little attention in …Little attention in …

• UN RSIM Rev 1.UN RSIM Rev 1.• EGM recommendations:EGM recommendations:““Countries should explore the possibility of using sample surveys Countries should explore the possibility of using sample surveys

to collect data on international migration, especially for those to collect data on international migration, especially for those aspects for which no other sources are available”aspects for which no other sources are available”

PROSPROS• In-depth analysisIn-depth analysis

determinants, distributional analysis, determinants, distributional analysis, impact (??)impact (??)• More flexibilityMore flexibility• Emigration (last resort?)Emigration (last resort?)

CONSCONS• Rare event, clusteredRare event, clustered• Sampling errorSampling error• Sampling frame (emigrants)Sampling frame (emigrants)• Richer info but … still limitations through proxy Richer info but … still limitations through proxy

respondentsrespondents

Survey options: prob vs. non-probSurvey options: prob vs. non-prob

Probability: finding rare eventsProbability: finding rare events• Huge sample?Huge sample?• 8 procedures (Kish, 1965)8 procedures (Kish, 1965)

DisproportionateDisproportionate Two-phaseTwo-phase

Non-probabilityNon-probability• Case studiesCase studies• Purposive geo selection (NIDI/Eurostat)Purposive geo selection (NIDI/Eurostat)• SnowballSnowball• Aggregation point intercept (Brazil-Aggregation point intercept (Brazil-

Nikkei)Nikkei)

Survey options: HH vs. non-HHSurvey options: HH vs. non-HH Passenger surveysPassenger surveys

• UK IPS (flows)UK IPS (flows) Low incidenceLow incidence Short questionnaireShort questionnaire

HH surveysHH surveys• Specialized Specialized

Preferred option but …Preferred option but …• Too costly/unfeasibleToo costly/unfeasible• Limited thematic coverageLimited thematic coverage

• Piggy-backingPiggy-backing Richer info (welfare?) but shorter migration moduleRicher info (welfare?) but shorter migration module Marginal costsMarginal costs Sampling issuesSampling issues LSMS/IHS (small sample; Albania), HBS/IES (high non-LSMS/IHS (small sample; Albania), HBS/IES (high non-

response; “resistance”); LFS (larger sample; response; “resistance”); LFS (larger sample; frequency; no welfare; Philippines)frequency; no welfare; Philippines)

Survey on Overseas Filipinos (SOF)Survey on Overseas Filipinos (SOF) Long tradition; now integral part of LFS.Long tradition; now integral part of LFS. 1982: 1-page rider to ISH1982: 1-page rider to ISH 1987: part of LFS (OFW only)1987: part of LFS (OFW only) 1993: expanded module, renamed (OF)1993: expanded module, renamed (OF) 2003: Master sample (51,000 HHs) 2003: Master sample (51,000 HHs) Estimates and characterize stock of Estimates and characterize stock of

overseas Filipinos, including OFW overseas Filipinos, including OFW (presently AND temporarily working (presently AND temporarily working overseas in last 5 year period) [1.2M in overseas in last 5 year period) [1.2M in 2004]2004]

Questionnaire Questionnaire

Contents / DesignContents / Design

Identifying a migrant in HHIdentifying a migrant in HH

Approach 1: “Typical” LSMS/IHSApproach 1: “Typical” LSMS/IHS• Self-reported hh membership Self-reported hh membership (“usually” eat and (“usually” eat and

live together)live together)

• No. months absent in past 12 months No. months absent in past 12 months Provisions, for HH head, new-comers …Provisions, for HH head, new-comers …

Several drawback:Several drawback:• Permanent migrants?Permanent migrants?• Exclusion based on arbitrary cut-offExclusion based on arbitrary cut-off• AmbiguousAmbiguous• Misses entire HHsMisses entire HHs

Identifying a migrant in HH Identifying a migrant in HH (cont’d)(cont’d)

Approach 2: Approach 2: ““in the last 5 years, did anyone in the last 5 years, did anyone who liveswho lives

or livedor lived with you go to live in another with you go to live in another country?”country?”

Captures recent migrants but …Captures recent migrants but …• Still ambiguousStill ambiguous• Arbitrary reference periodArbitrary reference period• Still misses entire HHsStill misses entire HHs

Identifying a migrant in HH Identifying a migrant in HH (cont’d)(cont’d)

Approach 3: Extended roster Approach 3: Extended roster (with flap)(with flap)

• List all present and former hh members List all present and former hh members irrespective of PoRirrespective of PoR

Captures all members but …Captures all members but …• Still ambiguousStill ambiguous• Incentive to underreport?Incentive to underreport?• Misses entire HHsMisses entire HHs

Identifying a migrant in HH Identifying a migrant in HH (cont’d)(cont’d)

Approach 4: Expanded fertility Approach 4: Expanded fertility module (Albania LSMS 2002)module (Albania LSMS 2002)• From 15-49 to “above 15”From 15-49 to “above 15”• List all women in age groupList all women in age group

List all children ever born from womanList all children ever born from woman PoR for still alivePoR for still alive

However …However …• Still possible undercountStill possible undercount

mother absentmother absent

• Misses entire HHsMisses entire HHs

Once identify (e)migrant …Once identify (e)migrant … How much information can you elicit How much information can you elicit

through proxy respondent? What’s the through proxy respondent? What’s the min-MAX amount of info?min-MAX amount of info?• Age, gender, occupation (before and during)Age, gender, occupation (before and during)• Length stay abroad/year of departure Length stay abroad/year of departure • Country of destinationCountry of destination• Living with spouse/childrenLiving with spouse/children• Legal status?Legal status?• Multiple episodes?Multiple episodes?

Recall methodsRecall methods• Less accurate through proxyLess accurate through proxy• Recall bias (Smith and Thomas, 2003; Som, Recall bias (Smith and Thomas, 2003; Som,

1973)1973)

Albania LSMS 2005Albania LSMS 2005 Expanded module on (permanent) Expanded module on (permanent)

migrants (non-hh members) plus migrants (non-hh members) plus contact information for tracking in D contact information for tracking in D countrycountry

Full histories and characterization of Full histories and characterization of migration of migration of currentcurrent household household members (15 years)members (15 years)

““Bound” gridBound” grid Clear time-marksClear time-marks

Migration histories of HH membersMigration histories of HH membersID CODEID CODE 19901990 19911991 19921992 19931993 19941994 19951995 19961996 19971997 19981998 19991999 20002000 20012001 20022002 20032003 20042004 20052005

   CC MM CC MM CC MM CC MM CC MM CC MM CC MM CC MM CC MM CC MM CC MM CC MM CC MM CC MM CC MM CC MM

                                                                                                  

                                                                                                  

                                                                                                  

                                                                                                  

                                                                                                  

                                                                                                  

                                                                                                  

                                                                                                  

                                                                                                  

                                                                                                  

                                                                                                  

                                                                                                  

                                                                                                  

What if entire HH moves?What if entire HH moves? If dwelling occupiedIf dwelling occupied

• Ask new occupantAsk new occupant About locationAbout location About relatives still in communitiesAbout relatives still in communities

If dwelling vacant/destroyedIf dwelling vacant/destroyed• Ask neighborAsk neighbor• Ask neighbor about relative still in communityAsk neighbor about relative still in community

If “dwelling moved”?If “dwelling moved”?• Internal migrantsInternal migrants

““Restricted” universe of analysisRestricted” universe of analysis Track them? Feasible?Track them? Feasible?

Tracking migrantsTracking migrants

““Replace” proxy respondentReplace” proxy respondent IssuesIssues

• Info needsInfo needs• AttritionAttrition• CostsCosts

Albania (“forward” tracking)Albania (“forward” tracking) Tonga (“backward” tracking)Tonga (“backward” tracking)

Tracking Albanian migrants in GreeceTracking Albanian migrants in Greece Contact infoContact info ProcessProcess

• Greece only; list of migrants with contactsGreece only; list of migrants with contacts• 11stst contact in Greece contact in Greece• Return visit in Fall (phone cards)Return visit in Fall (phone cards)• 22ndnd contact in Greece contact in Greece• InterviewInterview

High attritionHigh attrition• No contact infoNo contact info• Unable to locateUnable to locate• Islands (high costs)Islands (high costs)• Refusal (not high)Refusal (not high)• Returnees/high mobilityReturnees/high mobility

Selection bias(es)? (undocumented aliens)Selection bias(es)? (undocumented aliens)

ConclusionsConclusions Standards not uniformly adopted across Standards not uniformly adopted across

and within countries (depending on and within countries (depending on source), and changingsource), and changing

Definition to be adopted depends on Definition to be adopted depends on objective at hand and sub-populations of objective at hand and sub-populations of interestinterest

Census: stock, but …Census: stock, but … Registers: flows, but …Registers: flows, but … Survey: Surprisingly, still little attention …Survey: Surprisingly, still little attention … ““Weakest link”: emigration!Weakest link”: emigration!

• Better estimationsBetter estimations• Better characterizationBetter characterization• Better sampling framesBetter sampling frames

Next steps: WB’s role?Next steps: WB’s role?

2010 Round of PopCensus2010 Round of PopCensus• Influence Qx designInfluence Qx design• Min set of questions on immigrant stockMin set of questions on immigrant stock• Question on Emigrant?Question on Emigrant?

Approximation for stratification in sampling frameApproximation for stratification in sampling frame

Improve admin recordsImprove admin records• TFSCBTFSCB• Register (if available) and/or border crossingRegister (if available) and/or border crossing• Inter-institutional collaborationInter-institutional collaboration• Data accessData access

Next steps: WB’s role? Next steps: WB’s role? (cont’d)(cont’d)

HH surveysHH surveys• Support proper sample designsSupport proper sample designs

Sampling frames of emigrantsSampling frames of emigrants ““enhanced” PSU listing for 2-stageenhanced” PSU listing for 2-stage Oversampling in planned surveysOversampling in planned surveys

• Reduce undercount/misreportingReduce undercount/misreporting Fielding and validation of ≠ approaches Fielding and validation of ≠ approaches

(LSMSIV)(LSMSIV) Adjust for entire migrant householdsAdjust for entire migrant households

• Specialized vs. multi-purposeSpecialized vs. multi-purpose Better income-based measuresBetter income-based measures

Next steps: WB’s role?Next steps: WB’s role?(cont’d)(cont’d)

HH surveys HH surveys (cont’d)(cont’d)

• Improve contentImprove content Much more flexibility allowedMuch more flexibility allowed Emigrants, Returnees, … Emigrants, Returnees, … If migrant presentIf migrant present

• Histories of migrationHistories of migration• Retrospective data, determinantsRetrospective data, determinants

Through proxyThrough proxy• Minimal set of questions?Minimal set of questions?• Contact info for tracking (sub-sample?)Contact info for tracking (sub-sample?)

• Tracking surveysTracking surveys• Panel surveysPanel surveys

Make provision in baselineMake provision in baseline