Population and migration statistics system transformation – recent updates

In response to the coronavirus (COVID-19) pandemic and the suspension of the International Passenger Survey (IPS), we have reviewed our plans for the transformation of migration statistics.

We have accelerated our transformation plans to use administrative data to deliver new measures of migration and, as previously stated, have determined that the August 2020 Migration Statistics Quarterly Report (MSQR) is likely to be the last set of long-term migration estimates based on IPS data.

In March 2021, we published new experimental analysis using HM Revenue and Customs (HMRC) "Real Time Information" data to explore how the labour market is changing, and what insights this can give us about the UK population.

These data gave us important insights and since then, we have continued our work to bring together further sources from across the government to help build our understanding of the population and international migration since the pandemic began.

As part of this ongoing work, we have today (16 April 2021) published the following.

An article, Using statistical models to estimate UK international migration in the absence of the International Passenger Survey, which describes new modelling methods for estimating international migration for March 2020, Quarter 2 (Apr to June) 2020, and beyond. The work reported here is ongoing and it is important to note that all initial estimates will be provisional and subject to amendment as more data become available.

An article that uses the modelled migration figures, alongside provisional statistics on births and deaths, to provide early insights into how the population of the UK may have changed since our previous publication of mid-year population estimates. The data presented in this article are provisional and may change as additional data become available. A full set of official mid-year population estimates covering the year to mid-2020 will be published in summer 2021.

Today (16 April 2021) we have published our first in-depth look at the sources and methods being used in our admin-based migration estimates (ABMEs) research. International migration: developing our approach for producing admin-based migration estimates presents research into a new methodology for measuring international migration and the estimates included in it are not Official Statistics on migration. It is designed to help inform users on the progress of our approach for transforming migration statistics using administrative data, and our plans to further develop these in the future.

Our ABME report builds upon our previous research, where we identified a range of data sources held across the government that can help us to better measure migration, including immigration, income, benefits and education data. We will continue to develop our knowledge and methods, as well as seeking feedback from our users, to help design and deliver our new measures of international migration. The main focus of our ABME report centres on two sources of data, which have shown the greatest potential for the measurement of long-term migration:

• Department for Work and Pensions (DWP) Registration and Population Interaction Database (RAPID)
• Home Office visas and border data

RAPID provides a single coherent view of citizens' interactions across the breadth of systems in both DWP and HM Revenue and Customs (HMRC), including benefits, employment, self-employment, pensions and in-work benefit.

We are exploring the use of these data to determine signs of "activity" among the migrant population in the UK, and how we can use that information to infer migrant flows based on when that activity commenced (indicating arrival in the UK) and when it ends (indicating departure).

Home Office visas and border data provide a more direct measure of movement and can be used to identify when non-European Economic Area (EEA) nationals have entered or exited the UK.

Migration Statistics Quarterly Report (MSQR): August 2020, including long-term international migration estimates for the year ending March 2020

The latest long-term international migration estimates currently remain those based on International Passenger Survey (IPS) data for the period up to March 2020.

The period in which data were collected from the IPS covers up to 16 March 2020. The IPS was suspended on this date because of the coronavirus (COVID-19). The weighting methodology has been adapted to compensate for these missing data. This compensation means that the reporting period for this release remains unchanged.

As a result of the Migration Statistics Transformation Journey, the IPS being stretched beyond its original purpose, and the impact of the coronavirus pandemic, this is likely to be the last Migration Statistics Quarterly Report (MSQR) based on IPS estimates.

Processing and quality assurance of IPS data for Quarter 1 (Jan to Mar) 2020 identified a possible issue in the data, namely an unexpected large rise in the number of non-EU students interviewed in the IPS.

A detailed review of the data and associated processes suggests this may be because of the IPS being susceptible to sampling variability. This observation aligns with previous analysis, which identified that large numbers of students may travel at the same time because of course start dates, meaning that some IPS shifts may include clusters of student contacts. If this were to occur, the IPS data may overestimate the number of long-term student migrants. This is a limitation of using a sample survey.

Uncertainty of this type in the data is represented by the confidence intervals around the estimates, which can be viewed in the associated datasets. Because of this oversampling, an adjustment, in line with previous adjustments, has been applied to non-EU student immigration for the year ending Quarter 1 2020 estimates using Home Office (HO) visa allocations. This ensures we are providing the best possible estimates of migration based on all available sources. See Section 6 of the Migration Statistics Quarterly Report: August 2020 for more detail.

As it is recognised that international travel patterns changed significantly in 2020 because of the coronavirus pandemic, we also included in this release additional data and insights on recent travel patterns in the period up to the end of June 2020. See Section 8 of the Migration Statistics Quarterly Report: August 2020 for more detail.

As part of our transformation journey to make use of all available data sources to provide a richer and deeper understanding of migration, we are moving towards publishing a report on our first set of admin-based migration estimates (ABMEs) in early 2022.

This first ABME report will include data up to April 2021 and will therefore cover a time period affected by the coronavirus (COVID-19) pandemic, for which the International Passenger Survey (IPS) ceased to collect migration data (post March 2020). It will bring together and build upon the methods developed in our transformation work, incorporating new data from the RAPID and Home Office migration system as well as the results of the migration modelling work.

While ABME reports will replace the Migration Statistics Quarterly Report (MSQR) publication going forward, it is important to recognise that the move to ABME reports marks a change in how we will report migration estimates.

As we progress our ambition to maximise the value and benefits of admin data, the initial ABME reports will not report migration data in the same way as the MSQR. The current availability of admin data means that the time periods reported upon in the MSQR, and some of the underlying detail, such as reason for migration, will not be included in our initial ABME reports.

It is important to recognise that this short-term change in content is an important step towards the delivery of a transformed migration system, one that makes best use of all available data sources and underpins a new robust, sustainable and coherent population and migration statistics system.

Our ABME reports will demonstrate iterative progress towards a transformed migration system and will provide users with clear messages on our next steps and challenges. As such, the ABME reports will, like the MSQR, be classified as Experimental Statistics. As our work progresses, we look forward to being able to produce greater insights into migration patterns and statistics at an ever more granular level.

Our transformation mission is to provide the best insights on population and migration using a range of new and existing data sources to meet the needs of our users. This is increasingly important in a rapidly changing policy and societal context, where we know our users need better evidence to support decision-making at both national and local levels.

In addition to the outputs described in the earlier sections, we deliver analysis and insights into important migration topics based on user needs.

Previous analysis articles

The following analysis articles include further insights on international migration patterns and sectors:

• Coronavirus and non-UK key workers (November 2020)

• What can administrative data sources tell us about the patterns of presence of non-EU students? (February 2020)

• International migration and the healthcare workforce (August 2019)

• International migration and the education sector - what does the current evidence show? (May 2019)

We welcome your feedback on our latest updates and on our transformation journey. If you would like to get in touch, please contact us by email at pop.info@ons.gov.uk.