You asked
What methods are used to determine the total numbers of EU and non-EU immigrants in the UK in any one year?
Is it an approximate figure based on poll projections or an actual head count?
If the latter, how is the head count obtained?
We said
Thank you for your request.
We use the Annual Population Survey to determine the population of the UK by a resident's country of birth or nationality. The Annual Population Survey (APS) combines results from the Labour Force Survey (LFS -- see below) and the English, Welsh and Scottish Labour Force Survey boosts. These boosts increase the size of the sample.
The Labour Force Survey (LFS) is a household survey of people in the UK. It includes those deemed resident at private addresses, so covers students in halls of residence with parents resident in the UK. However, it does not cover most communal establishments. Its purpose is to provide information on the UK labour market but it includes data on a variety of other variables such as country of birth and nationality.
More robust estimates are available from the APS: APS datasets are produced quarterly with each dataset containing 12 months of data. There are approximately 300,000 persons per dataset.
To estimate the numbers of people migrating in and out of the UK we carry out interviews using the International Passenger Survey (IPS) at major air, sea and rail ports. You can find fuller details about the data sources and methodology in the migration statistics quarterly report (MSQR), most recently published in August 2019.
Alongside the MSQR we also published the findings of our latest research into data sources for international migration as we strive to improve their quality.
When accessing any of our files please read the 'notes, terms and conditions' contained within them.
Please do not hesitate to contact us directly on pop.info@ons.gov.uk, if you require anything further.