Estimation of Emigration from Estimation of Emigration from the United States using the United States using

International Data SourcesInternational Data Sources

Jason P. SchachterJason P. SchachterSenior Statistician, Senior Statistician,

Bureau of Statistics, ILO GenevaBureau of Statistics, ILO Geneva

United Nations Expert Group Meeting on Migration StatisticsNew York, NY, December 4-7, 2006

22

IntroductionIntroduction

Many countries, including US, do not Many countries, including US, do not collect emigration data.collect emigration data.

Needed for the estimation of Needed for the estimation of net net international migration.international migration.

Too problematic and expensive to Too problematic and expensive to collect information on US citizens living collect information on US citizens living abroad. abroad.

Attempt to use international data Attempt to use international data sources to estimate number of US sources to estimate number of US born/citizens moving abroad.born/citizens moving abroad.

33

How many US citizens live abroad?How many US citizens live abroad?

State Department’s estimate was 4.1 State Department’s estimate was 4.1 million in 1999. million in 1999.

One-quarter (1 million) in Mexico, One-quarter (1 million) in Mexico, 700,000 in Canada. Top 10 countries 700,000 in Canada. Top 10 countries had 70% of all US citizens living abroadhad 70% of all US citizens living abroad

Huge discrepancies in totals when Huge discrepancies in totals when compared to international data sources, compared to international data sources, though similar country rankings. though similar country rankings.

State Department estimates appear to State Department estimates appear to be two to three times larger then be two to three times larger then international data sources (closer to 1.5 international data sources (closer to 1.5 to 2 million). to 2 million).

44

US State Department vs. International Data Sources for Top 10 US Emigrant Countries

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

US State Dept International data source

55

About State Department dataAbout State Department data

State Department figures are “best guess” State Department figures are “best guess” estimatesestimates

Voluntary registered + an estimated number of Voluntary registered + an estimated number of non-registerednon-registered

Purpose of data is in case of an emergency Purpose of data is in case of an emergency evacuation, not to reflect exact numbers. evacuation, not to reflect exact numbers. Their accuracy is of low priority to the State Their accuracy is of low priority to the State DepartmentDepartment

Overestimation also possible due to failure to Overestimation also possible due to failure to deregister, as well as registration for short deregister, as well as registration for short stays abroad (compared to “usual residents” in stays abroad (compared to “usual residents” in other data sources)other data sources)

66

US military abroadUS military abroad

Inclusion or exclusion of US military personnel from Inclusion or exclusion of US military personnel from data sources adds to difficultiesdata sources adds to difficulties

According to pre-2001 military base report, one-According to pre-2001 military base report, one-quarter million officially reported, plus an equal quarter million officially reported, plus an equal number of dependents.number of dependents.

True size not reported for “security” reasons. True size not reported for “security” reasons. Does not include military stationed in Afghanistan Does not include military stationed in Afghanistan

and Iraq, among other places. and Iraq, among other places. Not normally included in foreign data (due to Not normally included in foreign data (due to

universe coverage, residency rules), but US universe coverage, residency rules), but US military, support staff, and dependents living off-military, support staff, and dependents living off-base could be included. base could be included.

Needs to be kept in mind when estimating number Needs to be kept in mind when estimating number of US abroadof US abroad

77

Using international stock data to Using international stock data to estimate “net migration”estimate “net migration”

Purpose of exercise was to investigate the Purpose of exercise was to investigate the feasibility of using international data sources feasibility of using international data sources to estimate the number of US citizens to estimate the number of US citizens moving abroadmoving abroad

Requested data on US citizens and/or US Requested data on US citizens and/or US born from the two most recent Censuses of 5 born from the two most recent Censuses of 5 countries: Canada, France, Italy, Poland, and countries: Canada, France, Italy, Poland, and the United Kingdom. (UNECE/EUROSTAT the United Kingdom. (UNECE/EUROSTAT data exchange initiative) data exchange initiative)

A number of measurement/data A number of measurement/data comparability issues need to be kept in mindcomparability issues need to be kept in mind

88

US Citizens vs. US BornUS Citizens vs. US Born By US law, US born is synonymous with US citizenshipBy US law, US born is synonymous with US citizenship Not treated as such in international data sources (self-Not treated as such in international data sources (self-

reported)reported) For example, 2001 Spanish Census counted 21,000 US For example, 2001 Spanish Census counted 21,000 US

born in US. 12,000 were foreigners, while 9,000 were born in US. 12,000 were foreigners, while 9,000 were Spanish.Spanish.

Dual “US-other” citizens usually not counted as US Dual “US-other” citizens usually not counted as US citizens while living abroad (and only some countries -citizens while living abroad (and only some countries -Austria, Canada, Greece, Ireland, Japan, Malta, Austria, Canada, Greece, Ireland, Japan, Malta, Portugal, Switzerland, and most of Eastern Europe –Portugal, Switzerland, and most of Eastern Europe –collect this information on their Censuses) collect this information on their Censuses)

Conversely, limiting definition to US born misses US Conversely, limiting definition to US born misses US citizens born abroad of American parents or citizens born abroad of American parents or naturalized US citizensnaturalized US citizens

99

Other measurement issues –data Other measurement issues –data comparabilitycomparability

Comparability between different data sources Comparability between different data sources (Census, registers, other administrative records, (Census, registers, other administrative records, border crossings). border crossings).

Limit analysis to Census “stock” data to reduce Limit analysis to Census “stock” data to reduce data comparability issues. No “flow” data. data comparability issues. No “flow” data.

Data quality --sampling and measurement error-- Data quality --sampling and measurement error-- Did not evaluate quality of data sources.Did not evaluate quality of data sources.

Different universes included in data sets, e.g. Different universes included in data sets, e.g. usual residence definitions (usual residence definitions (de jurede jure vs. vs. de factode facto), ), how treat those living temporarily abroad (e.g. how treat those living temporarily abroad (e.g. students)students)

Need consistent universes between data sources Need consistent universes between data sources (over time within country, and between countries)(over time within country, and between countries)

1010

Country resultsCountry results

Requested the age and sex distribution of Requested the age and sex distribution of enumerated US citizens and/or US born from the two enumerated US citizens and/or US born from the two most recent Censuses.most recent Censuses.

France, Italy, and Canada asked both country of birth France, Italy, and Canada asked both country of birth and citizenship on their two most recent censusesand citizenship on their two most recent censuses

UK only asked country of birthUK only asked country of birth Poland collected this information on its 2002 Census, Poland collected this information on its 2002 Census,

but not on its 1988 Census, so not able to estimatebut not on its 1988 Census, so not able to estimate Only Canada and Poland collect information on dual Only Canada and Poland collect information on dual

citizens (though not able to release Canada’s results citizens (though not able to release Canada’s results due to confidentiality restrictions)due to confidentiality restrictions)

1111

US Born and US Citizens enumerated by 2001 Italian Census, by Sex

0

10,000

20,000

30,000

40,000

50,000

US Born Female Male USCitizens

Female Male

1212

Estimation uses a “crude” residual Estimation uses a “crude” residual methodology (in brief)methodology (in brief)

Observe stock data at two points in time Observe stock data at two points in time (T1 and T2) from similar sources (e.g. (T1 and T2) from similar sources (e.g. Census)Census)

Survive T1 population to T2 (using age and Survive T1 population to T2 (using age and sex specific death rates), for which there is sex specific death rates), for which there is a comparable observed population. a comparable observed population. Difference between the survived and Difference between the survived and observed population is “net migration.”observed population is “net migration.”

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Estimation Methodology (in more Estimation Methodology (in more detail)detail)

From two most recent Censuses, establish a T1 (circa From two most recent Censuses, establish a T1 (circa 1990 Census) population of US born and/or citizens, 1990 Census) population of US born and/or citizens, and a similar T2 (circa 2000 Census) observed and a similar T2 (circa 2000 Census) observed population. population.

US born:US born: T1 population is survived (using age and T1 population is survived (using age and sex specific death rates based on the resident US sex specific death rates based on the resident US population for the T1 year) a number of years equal population for the T1 year) a number of years equal to the difference between T1 and T2. to the difference between T1 and T2.

The difference between the survived T1 and The difference between the survived T1 and observed T2 population is assumed to measure “net observed T2 population is assumed to measure “net international migration” between the US and that international migration” between the US and that given country over the T2-T1 time period. given country over the T2-T1 time period.

This figure is then divided by the time period to yield This figure is then divided by the time period to yield an average annual net migration figure an average annual net migration figure

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Estimation Methodology (cont.)Estimation Methodology (cont.)

Used same methodology for Used same methodology for US citizensUS citizens, but need , but need two additional components: birth of children to US two additional components: birth of children to US female citizens (added to the survived T1 total) and female citizens (added to the survived T1 total) and US citizens who naturalized to another country –and US citizens who naturalized to another country –and revoked their US citizenship-- (subtracted from the revoked their US citizenship-- (subtracted from the survived T1 total). survived T1 total).

Proved difficult to incorporate additional components. Proved difficult to incorporate additional components. The number of births to US females is not necessarily The number of births to US females is not necessarily

equal to a number of new US citizens (also misses equal to a number of new US citizens (also misses potential births to non-US nationals married to US potential births to non-US nationals married to US males). males).

Not able to find any public records on number of US Not able to find any public records on number of US citizens who naturalized in these countries. citizens who naturalized in these countries.

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Method makes some dangerous Method makes some dangerous assumptionsassumptions

The US population living abroad has the same age The US population living abroad has the same age and sex-specific death and birth rates as the US and sex-specific death and birth rates as the US resident populationresident population

Needed to make assumptions about the age Needed to make assumptions about the age distribution of Americans living abroad (people distribution of Americans living abroad (people were equally distributed within each age cohort)were equally distributed within each age cohort)

Improved coverage (measurement) of Improved coverage (measurement) of foreigners/foreign-born from one Census to next foreigners/foreign-born from one Census to next might be the actual reason for apparent “net might be the actual reason for apparent “net migration gain”migration gain”

Measurement error around figures, from sample Measurement error around figures, from sample based data, could be resulting in “net migration.”based data, could be resulting in “net migration.”

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((An even cruder) estimate of flows to and An even cruder) estimate of flows to and from specific countriesfrom specific countries

Calculated a rough estimate of the in-flow of US Calculated a rough estimate of the in-flow of US born/citizens to the US from specific countries, using the born/citizens to the US from specific countries, using the US Census 2000 residence 5 years ago question, and US Census 2000 residence 5 years ago question, and dividing by five.dividing by five.

Then used our net migration estimate combined with the Then used our net migration estimate combined with the in-flow estimate to calculate an out-flow estimate. in-flow estimate to calculate an out-flow estimate.

Problems: US Census could include different universes Problems: US Census could include different universes than other countries (e.g. students and military) than other countries (e.g. students and military)

A five-year flow divided by five is not equivalent to a one-A five-year flow divided by five is not equivalent to a one-year flow (migrants could have returned at any time year flow (migrants could have returned at any time during the 5 year period, migrants could have left and during the 5 year period, migrants could have left and returned between 1996 and 2000, or they could have returned between 1996 and 2000, or they could have moved to multiple countries during the 5 year period), all moved to multiple countries during the 5 year period), all of which underestimates the true size of country-specific of which underestimates the true size of country-specific flows. flows.

Despite these problems, it is our best guess estimate of Despite these problems, it is our best guess estimate of flows to and from these countries. flows to and from these countries.

1717

Estimated Annual Inflow, Outflow, and Net Migration of US Born to/from the United States

0

5,000

10,000

15,000

20,000

Canada GreatBritain

France Italy

Estimated Inflow Estimated Outflow Average annual net migration gain from US

1818

Evaluation Evaluation

Net migration results looked OK (at face Net migration results looked OK (at face validity, given there are no sources to validity, given there are no sources to compare). compare).

Canada and Great Britain had roughly the same Canada and Great Britain had roughly the same size of flows and net, despite a larger stock size of flows and net, despite a larger stock population in Canada? population in Canada?

Large number of dual-nationals in Poland Large number of dual-nationals in Poland (30,000 vs. 1,000 US citizens). (30,000 vs. 1,000 US citizens).

US born easier to calculate than US citizens US born easier to calculate than US citizens (dual citizen problem, components needed to (dual citizen problem, components needed to survive population) ---however citizenship data survive population) ---however citizenship data are more readily available from different are more readily available from different sourcessources

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ConclusionsConclusions

How to deal with US military and dependentsHow to deal with US military and dependents Data quality issues—need to evaluate international Data quality issues—need to evaluate international

sources sources Is this method possible combining different data Is this method possible combining different data

sources (Census, house hold surveys, population sources (Census, house hold surveys, population registers, etc.)?registers, etc.)?

Reliability of method is questionable, since it could Reliability of method is questionable, since it could mask fluctuations over time.mask fluctuations over time.

Recommend using US born data to calculateRecommend using US born data to calculate Recommend expanding project to include top thirty Recommend expanding project to include top thirty

receiving countries –but special tabulations from receiving countries –but special tabulations from these countries will be needed- these countries will be needed-

2020

Contact InformationContact Information

Jason Schachter, Ph.DJason Schachter, Ph.D

Bureau of Statistics, Room 5-51Bureau of Statistics, Room 5-51

4, Route des Morillons4, Route des Morillons

CH-1211 Geneva, SwitzerlandCH-1211 Geneva, Switzerland

Phone: +41 (0)22 799 6954 Phone: +41 (0)22 799 6954

E-mail: g1stat@ilo.orgE-mail: g1stat@ilo.org