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Background to IMPS

As a result of enhanced complex lifestyles and changes in migration over the last decade, it has become increasingly important to have high quality statistics on migration and the population, for policy development and for planning and providing public services. Achieving this aim is challenging.

It has long been recognised that international migration is one of the most difficult components of population change to measure accurately. Naturally, migration figures are high although numbers of immigrants and emigrants vary substantially by region within the UK. There is no single, comprehensive source of data which can provide the information (at national and/or local levels) that is required for these statistical purposes and planning.

It is in the context of these pressures that the work of improving migration and population statistics has been prioritised. It is focused on making improvements to the methods and data sources used to estimate the population at national and local levels during the intercensal period (the time between two Censuses, ten years). These improvements are needed to minimise the risk of divergence between the rolled-forward, mid-year population estimates and the 2011 Census-based population estimates, and to better understand the differences that remain. ONS is working in partnership with other government departments to achieve this aim.

The key strands of the Improving Migration and Population Statistics (IMPS) research are:

  • migration research (both international and internal within the UK)

  • collaborative work with local authorities to investigate the potential for making greater use of administrative data sources to improve local population estimates

  • population definitional issues

More information on the progress made on each of these strands of research is provided in the Updates and Reports pages.

In May 2006, the Office for National Statistics (ONS) set up an Interdepartmental Task Force on Migration Statistics with other government departments. The objective of the task force was to recommend timely improvements that could be made to estimates of migration and migrant populations in the UK, both nationally and at local level. The final report of the task force was published on 15 December 2006 and can be accessed from the Archive Updates section.


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