Dear Ed,
I am writing to you with an update on how we have developed long-term international migration estimates since the last OSR progress report in December 2023. There has been considerable improvement to the output, and this work is continuing. Our International migration research, progress update, published today, provides an update on the research underway that will further improve our admin-based migration estimates.
It is important to recognise in the last few years there has been significant research into administrative data for migration estimates. Our increased understanding of the Home Office Borders and Immigration (HOBI) data and the Department for Work and Pension’s (DWP’s) Registration and Population Interaction Database (RAPID), and how to use them, have helped us to improve long-term international migration (LTIM) statistics. We continue to review other potential data sources that could be used in the future to help improve these statistics.
In November 2025, we reached a major milestone that transformed this output. We published our work introducing new methods for British National migration and EU+ migration. This meant that for the first time, LTIM estimates no longer relied on International Passenger Survey (IPS) data. This was a significant step in improving the quality of these statistics, moving away from reported intentions to migrate and towards observable behaviour in admin data. When making any changes, we have internal and external reviews in place to ensure improvements to methods and data sources are researched and tested before publication. We also work hard to ensure users are well informed of any improvements.
Independent advice and input from users have been crucial to ensure the plans and benefits of innovating and improving these estimates are achieved, valued and communicated. To support this, we have refreshed our approach to engagement, including through the formation of the National Statistician’s Advisory Panel on Migration Statistics, Migration Statistics User Group, and the Methodological Assurance Review Panel International Migration subgroup. These provide us with independent advice on the development and use of our migration statistics.
Our Quarterly update on population and migration statistics provides a long-term look ahead, setting out our plans and progress. This is circulated via our regular newsletter to a wide network to ensure users are aware of any changes. We also follow each LTIM publication with a webinar.
We continue to look at how we can improve the quality and presentation of our statistics. This includes sharing more on measures of uncertainty. Uncertainty estimates for administrative data sources require novel methods, which have been developed and improved over time, making use of independent expert feedback. Our latest research update published today includes a summary of our work on uncertainty estimates.
For our upcoming release in May we plan to include more comprehensive estimates of uncertainty, incorporating more information about the sources that affect the stability of the estimates. We also aim to make uncertainty more prominent in the bulletin, helping our users understand the likely stability of the headline migration estimates.
We will continue to update OSR through our regular meetings and I would be happy to discuss any aspect of this update.
Yours Sincerely,
Mary Gregory