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A model-based approach for estimating international emigration for local a uthorities

A model-based approach for estimating international emigration for local a uthorities

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A model-based approach for estimating international emigration for local a uthorities

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  1. A model-based approach for estimating international emigration forlocal authorities Brian Foley, Office for National Statistics BSPS day meeting London School of Economics 16th 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 National IPS direct estimate Regional Distribute using IPS 3 year average Intermediate (NMGo) Distribute using regression model 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. Emigration model specification Covariate 1 IPS estimate of LA emigration (3 year average) LA level data Covariate i Covariate 1 Covariate 2 Covariates selected by stepwise model in more than one year Stepwise model Covariate 3 Multicollinearity testing 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) 2001 Census Number of retired people (-) Annual Population Survey Number of lone and working parents (-) Population Statistics Division, ONS Number of students in Higher/Further education (+) Number of people of Western Europe country of birth (+) Number of people of Oceania country of birth (+) LA emigration estimates 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 (+)

  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. Emigration model specification Covariate 1 IPS estimate of LA emigration (3 year average) LA level data Covariate i Covariate 1 Covariate 2 Covariates selected by stepwise model in more than one year Stepwise model Covariate 3 Multicollinearity testing 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 2011 Census Number of hostels (+) Annual Population Survey Migrant Worker Scan Number of people of North American country of birth (+) Number of people of Oceania country of birth (+) LA emigration estimates Number of people of African country of birth (+) Number of in-migrants of EU8 nationality (+) Number of people aged 16+ in employment (-)

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

  22. Emigration as % of LA population Modelled estimates of emigration as a percentage of local authority population, year ending mid-2011 <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 • 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

  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 ?