1. A model-based approach for estimating international emigration for local authorities Brian Foley, Office for National Statistics BSPS day meeting London School of Economics 16 th May 2013

2. Presentation format Background information -importance of accurate international migration estimates Issues with estimating emigration from local authorities (LAs) ONS emigration model -overview -updating of the model for the year ending mid- 2012 emigration estimates Future work

3. Need for accurate international migration estimates at local authority level International migration is a key component of population change Accurate estimation of migration flows necessary for LA mid-year population estimates

4. Definition ONS use the United Nations recommended definition of an international long-term migrant: -a person who moves to a country other than that of his or her usual residence for a period of at least a year (12 months), so that the country of destination effectively becomes his or her new country of usual residence

5. Estimating international migration at local authority level Migration Statistics Improvement Programme Administrative data to distribute immigration totals from International Passenger Survey (IPS) -National Insurance number -Higher Education Statistics Agency -Flag 4s from the GP Patient Register What about emigration ??

6. Emigration at local authority level – difficult to estimate No administrative or survey data sources exist that provide information on long-term emigration from LAs Small sample size of emigrants in the IPS

7. International Passenger Survey, 2002 to 2011 Source - http://www.ons.gov.uk/ons/rel/migration1/long-term-international-migration/2011/1-02-ips-margins-of-error--1975-2011.xls

8. IPS estimates of emigration at national (2002-2011) and regional level (2011) Source - http://www.ons.gov.uk/ons/rel/migration1/long- term-international-migration/2011/1-02-ips-margins-of- error--1975-2011.xls

9. Emigration estimates for the different levels of geography IPS direct estimate Distribute using IPS 3 year average Distribute using regression model National Regional Intermediate (NMGo) Local authority

10. Estimating emigration at local authority level ONS employs a Poisson regression model Produces estimates of international emigration at LA level (where IPS data are insufficient) by borrowing strength from other data sources -Census -Survey -Administrative

11. Overview of the emigration model Fitted model based on relationship between number of emigrants leaving an LA (IPS- based) and a number of LA-level socio- economic and demographic variables (covariates) Strengths of model: -availability of data for all LAs -more robust estimates

12. Consideration of covariate data Variety of factors associated with why emigrants would leave an area Data that capture both a person’s desire and ability to emigrate

13. Relationship between international long-term emigration and socio-demographic variables at local authority level in England and Wales, year ending mid-2011

14. Stepwise model IPS estimate of LA emigration (3 year average) Covariate 1 Covariate 2 Covariate i Covariate 3 Covariate 1 Multicollinearity testing Covariates selected by stepwise model in more than one year LA level data Emigration model specification Covariate i Final model LA emigration estimates constrained to sum to the relevant NMGo estimate

15. Fitting the final model Geographic indicators included Model fitted for each year ending mid-2002 to mid-2006 Fixed set of model covariates used -improves quality of time series General patterns can be observed -relationship between covariates and IPS emigration estimates

16. Original emigration model (finalised 2010) LA emigration estimates Number of retired people (-) Number of lone and working parents (-) Number of students in Higher/Further education (+) Number of people of Western Europe country of birth (+) Number of people of Oceania country of birth (+) Number of people of North American country of birth (+) Number of household spaces in terraced housing (+) Number of household spaces in shared housing (+) Number of hostels (+) Number of people of Indian ethnicity (-) Number of internal in-migrants (-) Number of international in-migrants (+) Annual Population Survey 2001 Census Population Statistics Division, ONS

17. Updating the model for the year ending mid-2012 emigration estimates Rationale -availability of 2011 Census data -availability of administrative data -appropriate to re-examine the underlying relationships in the model over a more recent time- period -change in dynamics of international migration to/from UK since the mid-2000s

18. Covariate data sources employed 2011 Census data -country of birth, ethnicity, housing status Administrative data available to ONS -Higher Education Statistics Agency (HESA) -Migrant Worker Scan Annual Population Survey -economic activity data Home Office -crime statistics

19. Stepwise model IPS estimate of LA emigration (3 year average) Covariate 1 Covariate 2 Covariate i Covariate 3 Covariate 1 Multicollinearity testing Covariates selected by stepwise model in more than one year LA level data Emigration model specification Covariate i Final model LA emigration estimates constrained to sum to the relevant NMGo estimate

20. Updated model for year ending mid-2012 emigration estimates at LA level Number of hostels (+) Number of people of Oceania country of birth (+) Number of people of African country of birth (+) Number of people aged 16+ in employment (-) Number of people of North American country of birth (+) Number of in-migrants of EU8 nationality (+) LA emigration estimates Annual Population Survey 2011 Census Migrant Worker Scan

21. Range from ca. 20 to 8,000 Higher emigration flows associated with London and the larger regional cities <250 250-499 500-749 750-999 1,000-1,999 2,000-3,999 4,000-6,999 >7,000 Modelled estimates of emigration from local authorities in England and Wales, year ending mid-2011 Modelled emigration estimates

22. Range from ca. 0.2% to 6.0% Modelled emigration estimates less than 2% of the LA population in 340 of the 348 LAs in England and Wales <0.20 0.20-0.34 0.35-0.49 0.50-0.74 0.75-0.99 1.00-1.49 1.50-2.49 >2.50 Modelled estimates of emigration as a percentage of local authority population, year ending mid-2011 Emigration as % of LA population

23. Future work Ongoing research into developing an improved modelling approach for producing emigration estimates at LA level -identify additional covariates, other data sources -capture forthcoming changes in international migration patterns to/from UK -reassess how geographic effects are captured and accounted for

24. Thank you for your attention Any questions ?