New Alternatives for Estimating Net Migration to the United States Using the American Community Survey

1. New Alternatives for Estimating Net Migration to the United States Using the American Community Survey Alexa Kennedy-Puthoff David Dixon Sonya Rastogi Dean Judson Population Division, U.S. Census Bureau Presented at the United Nations Expert Group Meeting on Measuring International Migration, December 2006.

2. Estimates of International Migration to the United States

3. Population Estimates • The U.S. Census Bureau produces annual estimates of the population and demographic components of change (births, deaths, and migration). These estimates are published at the national, state, and county level. • Estimates are used in: federal funding allocations, as denominators for rates time series, and as survey controls. • One component of the population estimates is net international migration, defined as the net movement across U.S. (50 states and the District of Columbia) borders.* * The movement of U.S. military personnel across U.S. borders and the in-migration of native U.S. citizens who are not members of the military are included in the population estimates separately from the net international migration component. http://www.census.gov/popest/estimates.php

4. Estimates of Net International Migration, 1990-2006 (in thousands) *

5. Net International Migration (NIM) • The Net International Migration component of the population estimates consists of three parts: 1. Net migration of the foreign-born population (NFB) 2. Net movement between Puerto Rico and the U.S. (50 states and D.C.) (PR) 3. (Net) emigration of native population (NEMIG) NIM = NFB + PR – NEMIG • NFB accounts for over 90 percent of the total NIM component. This research focuses on the construction of this component.

6. Using ACS Data to Estimate Net International Migration

7. What is the American Community Survey (ACS)? • Replaces census sample data (long-form questionnaire) • Content similar to census long form • Samples every year and spreads sample over 12 months • Monthly data collection • Annual estimates • Low levels of geography

8. ACS Questions Citizenship Status Residence One Year Ago Native Foreign born Year of Entry

9. Weighted Estimates of the Population (in thousands) Citizenship Imputation Rates universe: total population Source: American Community Survey, 2000-2004

10. Single Year Change(Current Method)

11. - Single Year Change Change in FB population during interval. SYC = FB t2 – FB t1 Deaths Deaths to FB population during interval PR Net migration between the U.S. (50 states and D.C.) and Puerto Rico NEMIG Native emigration NIM Net International Migration + + = Single Year Change • The current method used to estimate net migration of the foreign born • Based on the change in the number of foreign born counted in ACS in time 1 compared with time 2, with an adjustment for deaths to the foreign born during the period

12. Single Year Change: Estimates and Bounds universe: total foreign-born population, t1 and t2 (in thousands) * Data for 2000-2002 were re-weighted to a consistent series of population estimates.The bounds shown here represent a 90-percent confidence interval. Source: American Community Survey, 2000-2004

13. Problems with NFB Estimates Based on Single Year Change • High standard errors • Sensitive to changes in survey population controls • Annual reweighting of ACS data required to provide consistent series of NFB estimates

14. Year of Entry

15. Year of Entry Was Prior Calendar Year • Estimates utilize data on the year of U.S. entry of the foreign born • The “Year of Entry Was Prior Calendar Year” universe for NFB contains those who indicated they entered the U.S. in the year prior to the survey - - Year of Entry Was Prior Calendar Year Foreign born who have a year of entry that is the year prior to the survey. FBEMIG Emigration of the foreign-born population during interval PR Net migration between the U.S. (50 states and D.C.) and Puerto Rico NEMIG Native emigration NIM Net International Migration + =

16. Year of Entry Was Prior Calendar Year: Estimates and Bounds universe: foreign-born population, entered in year prior to the survey (in thousands) * Data for 2000-2002 were re-weighted to a consistent series of population estimates.The bounds shown here represent a 90-percent confidence interval. Source: American Community Survey, 2000-2004

17. Year of Entry:Imputation Rates universe: foreign-born population (in percent) universe: foreign-born population, entered in year prior to the survey (in percent) Source: American Community Survey, 2000-2004

18. Problems with NFB Estimates Based on Year of Entry • High imputation rates for Year of Entry • Conceptual ambiguity / survey question interpretation difficulties • Method requires an estimate of foreign-born emigration

19. Residence One Year Ago

20. Residence One Year Ago Was Abroad • Estimates utilize data on the residence of the foreign born in the year prior to the survey • The “Residence One Year Ago Was Abroad” universe for NFB contains those who indicated they were abroad (outside the U.S. or U.S. outlying areas) one year ago - - Residence One Year Ago Was Abroad Foreign born, who were “abroad” one year ago. FBEMIG Emigration of the foreign-born population during interval PR Net migration betweenthe U.S. (50 states and D.C.) and Puerto Rico NEMIG Native emigration NIM Net International Migration + =

21. Residence One Year Ago Was Abroad: Estimates and Bounds universe: foreign-born population, residence one year ago was abroad (in thousands) * Data for 2000-2002 were re-weighted to a consistent series of population estimates.The bounds shown here represent a 90-percent confidence interval. Source: American Community Survey, 2000-2004

22. Residence One Year Ago:Imputation Rates universe: foreign-born population (in percent) universe: foreign-born population, residence one year ago was abroad (in percent) Source: American Community Survey, 2000-2004

23. Problems with NFB Estimates Based on Residence One Year Ago • No residence rules for prior residence • Method requires an estimate of foreign-born emigration

24. Comparisons

25. Residence One Year Ago- and Year of Entry- Based Inflows, and Single Year Change (Net Movement) (in thousands)

26. Differences in Quality and Robustness Among Estimates • SEROYA<SEYOE<<SESYC • For the foreign born, imputation rates of place of residence one year ago are lower than those of year of entry

27. Next Steps

28. Components of NIM Warranting Further Investigation • Emigration • Coverage • Puerto Rico

29. Ideas for Estimating Emigration • Record Linking Methods • Current Population Survey (CPS) method • Administrative Records (ADREC) method • Multiplicity Survey Methods • Data Exchange Methods

30. Ideas for Estimating Emigration • Residual Methods • 10-year • 1-year ACS using foreign-born population counts • 1-year ACS using internal migration information

31. Sources of Undercoverage of the Foreign Born • Complex Housing Arrangements • Irregular Housing Units • Language Barriers • Fear of Government and Immigration Authorities • High Degrees of Mobility • ACS Two-Month Residency Rule

32. Estimation of Undercoverage of the Foreign Born • Various Methods and Assumptions • Wide Ranging Estimates for Segments of Foreign Born • Example - Range of 10 to 50 percent undercount for unauthorized

33. Immigration Statistics Staff • (301) 763-2411 • Dean H. Judson, Chief • http://www.census.gov/population/www/socdemo/foreign.html