The panel welcomed the improved process to arrive at migration assumptions for National Population Projections involving expert and user input. It suggested some post-publication work to look at sensitivity analyses for future projections to understand how much impact the assumptions have, such as the time periods used for the age and sex assumptions.
The panel welcomed the production of a migration data strategy. It recommended the strategy includes plans to make data available outside of government, both to generate research on international migration and to test the quality of the data and methods. The panel highlighted the importance of transparency around processes and statistics.
The panel welcomed work to produce estimates of non-UK born population. It highlighted the importance of clearly communicating that the publication may be inconsistent with data produced using other methods, and that further development work will be required to reconcile different estimates.
The panel suggested that the current structure of the LTIM bulletin is sensible and does not need to change significantly. It welcomed proposals to include more detailed breakdowns, for example by nationality grouping, and suggested that these should be included in accompanying data tables rather than the main bulletin.
Introduction
The Chair opened the panel meeting and welcomed members.
The Chair noted there was one outstanding action from the previous meeting relating to providing data on the number of days EUSS status holders spend inside and outside the UK. The Panel clarified that the intent was to understand the distribution of days spent in the UK, rather than a single summary measure, to help assess cut‑off rules for residency classification. ONS will take this away to investigate.
Key messages from Methodological Assurance Review Panel: Migration statistics sub-group
The Methodological Assurance Review Panel: Migration Statistics sub-group has not met since the last report.
Key messages were noted from the Migration Statistics User Group
The Migration Statistics User Group discussed the work to produce country of birth and nationality statistics, relating to estimates of the non-UK born population. There was a preference for both nationality and country of birth estimates with breakdowns at country, region, parliamentary constituencies and LA level being felt to be useful.
Other breakdowns for non-UK born estimates which would be useful for users include age breakdowns, arrival route, reason for migration, immigration status and individual nationality.
The uses of nationality estimates would include policy development including tax and benefits, employment rates, migration policy (including analysis), service planning, international comparisons and higher education planning.
The uses of country of birth were highlighted for service planning at LA level, comparisons over time and international comparisons.
The group indicated that an annual publication of estimates by non-UK born population would be sufficient for most needs.
The group received an update from the Home Office and ONS on what will be published on 21 May, noting the Home Office will be publishing data on age assessments and annual migrant journey report as part of the suite of publications. ONS will be publishing an article on British nationals emigration and estimates of the non-UK born population as well as addressing 2 of the limitations which were explained in November to improve long-term international migration estimates.
The group noted the presentation on No Recourse to Public Funds (NRPF) Connect which draws on data from those seeking social service support from different LAs and produces reports which includes referrals by immigration status, supported households by immigration status and support costs, and the helpful insights this provides in the absence of national data on NRPF.
The group noted the presentation from the South East Strategic Migration Partnership and the data which goes in to create the data dashboard which is a tool used for planning and delivering local support services such as translation.
Migration assumptions in the 2024‑based population projections
The ONS presented to the group the key findings from the newly published 2024-based National Population Projections. This included the current expectation that the UK population is expected to reach 71 million by mid‑2034, showing a slower growth than projected in the 2022‑based projections.
Parameters and assumptions used in the projections were discussed and the group agreed the work would benefit from formal sensitivity analysis on these (for example stay rates and age/sex distributions). Members suggested that internal exploratory analysis could help ONS understand which assumptions have the largest impact on outcomes.
The group discussed the use of pre‑2022 age and sex profiles and whether alternative periods might materially alter results.
The group welcomed the improved integration of migration expertise into the population projections and considered the process to be a clear improvement on previous rounds.
Update on ONS migration statistics strategy
The ONS followed up their previous presentation on the new migration strategy by clarifying its objective: To produce trustworthy, timely and high‑quality, long‑term migration statistics that support public understanding and policy.
The strategy will be broken down into short, medium and long-term goals over the next five years and beyond (post 2031 Census). Four pillars of the strategy were identified: reliable data sources, high‑quality methods, trustworthiness and effective communication.
The group reiterated the importance of transparency alongside communication, including clarity over assumptions, adjustments and uncertainty.
The potential role of external researchers in helping to explore data and methods, subject to legal and data‑sharing constraints was discussed, including how to make this possible.
The panel also wanted ONS to be clear about their role within the wider Government Statistical Service when describing strategic objectives.
Update on population stocks by country of birth and nationality
ONS provided an update on work to reintroduce population stock estimates by country of birth and nationality, which had been paused after 2021.
The short-term ambition is to publish a non‑UK‑born population estimate in the May 2026 Long‑Term International Migration (LTIM) bulletin. The estimate uses a cohort‑component approach, rolling forward from Census 2021 using migration flows and deaths data. Medium‑term ambitions include use of the Transformed Labour Force Survey, with longer‑term aspirations to develop admin‑based solutions.
Panel members agreed it was important to publish indicative estimates but be explicit that the methods are still in development. Clear caveats must be made, especially where estimates may differ from those implied by labour market surveys.
User engagement indicates demand for both nationality and country‑of‑birth statistics, particularly for use as denominators and contextual information.
The group also agreed that using multiple methods was seen as helpful for quality assurance, provided differences are explained clearly.
