Transforming migration statistics: how better data is helping us develop deeper insights

Providing more detailed statistics and analysis on UK migration is one of the ONS’ top priorities. Here Jay Lindop explains how access to new data is helping us to reveal a better and more useful picture of migration.

The figures produced at the ONS Centre for International Migration tell the story of the latest trends in migration to and from the UK. We currently focus on two key concepts: ‘long-term migration’ and ‘short-term migration’, which are defined based on the length of time someone intends to stay in the UK or abroad.

While these statistics provide important information to support policy decision-making and public services, our users have told us that they also need more detailed evidence on migration, to better reflect the complexity of modern travel patterns.

In 2019 we set out our plans to transform the way we produce migration statistics, to better meet the needs of our users. Working in partnership across the Government Statistical Service (GSS), we are progressing a programme of work to put administrative data at the core of our statistics.

Today’s research reports show our latest progress to review the way we measure and define concepts such as long-term migration, to harness the opportunities that new data sources give us to provide a richer and deeper evidence base. This will feed into our plans for transforming migration statistics between now and 2023.

What have we found?

Our latest research has continued to demonstrate how administrative data can give us a better understanding of people’s travel patterns and provide more insights on migration than our current survey source, the International Passenger Survey (IPS).

Working in collaboration with the Home Office, we have investigated how we can use Exit Checks data to measure our existing statistical definitions, alongside developing alternatives that look at migration in a different way and provide new insights.

For example, we currently define migrants as ‘long-term’ if they respond to the IPS by saying they intend to move to the UK for 12 months or more. However, the actual time they spend in the country could vary depending on whether they are studying at university, working in full-time or seasonal employment, or regularly travelling abroad for family reasons.

We are therefore developing methods for using Exit Checks data to better reflect the actual time non-EU migrants spend in the UK. Our latest research presents two new approaches, one looking at long-term migrants who are here for over half the year in total (6 months or more) and the other looking at those who are here for the vast majority of the year (10 months or more).

Alongside this, we have also published a case study showing how the non-EU university student population changes throughout the year, using Exit Checks and Higher Education data for England and Wales.

This shows that during the year, less than half of undergraduate students were in the country for more than 10 months. This is what we may expect to see, given that students often travel home during the university holidays. However, our analysis shows that there are differences in patterns for undergraduate and postgraduate students, with postgraduates tending to spend more time in the UK during the year on average. Why is this important? It shows how we need to understand different groups of migrants when we’re defining concepts such as long-term migration using administrative data, to make sure we develop rules that count people in an appropriate way.

What next?

Our work to review the way we define migration is on going and there’s more we need to do. We’re not planning to replace our existing long-term or short-term migration measures and we will continue to use internationally comparable definitions. However, we want to explore definitions that can provide further insights and we want your feedback on how we should develop our methods further. Are we heading in the right direction or are there new or alternative definitions that would better meet your needs?

Alongside gathering feedback, we’re also working across government to bring in further data sources to help us fill evidence gaps on migration to and from the EU. This will support our work to develop new methods for measuring long-term migration using administrative data, but also inform how we better capture short-term and circular (or ‘repeat’) migration in future.

In the shorter-term, we’re also using administrative data sources from the Home Office and the Department for Work and Pensions to refine the preliminary adjustment method we applied to our Migration Statistics Quarterly Report in August 2019 to provide our best assessment yet of migration. The latest figures will be published on 27 February, alongside which we’ll also publish an update on our plans for 2020.

Jay Lindop is the Deputy Director of the Centre for International Migration