National Statistical

The coronavirus pandemic led to huge changes in all our lives. Understanding international migration when people’s movement was restricted to manage COVID-19 as well as at a time of change following Brexit has been challenging. Here Jay Lindop provides insights into the work of the ONS to estimate migration flows during this period as well as our wider population plans for the coming months.

Today we’ve published our first set of provisional estimates to cover year ending June 2020 to year ending June 2021, based on new experimental methods. This covers a whole year when migration behaviour was impacted by the restrictions imposed to manage the coronavirus pandemic as well as ongoing changes in migration policy following Brexit.

In line with our mission to use all available data sources, for non-EU migration numbers we’ve used Home Office visa data, while we’ve estimated EU migration using Registration and Population Interaction Database (RAPID) created by the Department for Work and Pensions (DWP).

Combined, they show, despite various restrictions on movement in place over the 12 months, that more people arrived in the UK than left. Non-EU immigration was the driver of the net migration estimated at around 239,000, with other data sources pointing to an increase in non-EU student arrivals.

As set out in our transformation plans, we’re moving away from relying solely on broad sample survey data the International Passenger Survey (IPS) provides – something we’ve long said has been stretched beyond its intended purpose. We’re moving towards incorporating administrative data, which are based on actual behaviours rather than intentions, to produce our estimates.

However, understanding the data in a time of change following Brexit and the pandemic has been challenging and, as more data becomes available, we have to adapt our methods accordingly. These new experimental methods are a departure from the modelled IPS one previously published, so therefore are not comparable.

At this time, we have not provided a longer back series due to the experimental nature of the methods we’ve used, planned revisions of migration estimates following the release of Census 2021 results later this year and the subsequent rebasing of mid-year estimates.

We announced earlier this week the first England and Wales census results will be published on June 28. These will lay the foundation for measuring the population going forward but also allow us to understand much more about how the population has changed over the past decade. One key aspect for us will be to rebase both our population and migration estimates for the past decade. We will only do that once we are confident in our measures and have access to all data sources available to us, including the gold standard census.

Improving our understanding of the population

Alongside what we will learn from Census 2021 about the population over the last decade we will continue our research to produce the best possible statistics using existing data sources. Our update published today on how we are responding to the Office for Statistics Regulation (OSR) review on population estimates and projections outlines the progress we have made on their recommendations and the work that we will continue in the coming months. In addition, our publications today go some way to responding to OSR’s review of migration statistics. They have encouraged us to improve and broaden our user engagement as well as ensure we have coherent plans across our transformation work.

We welcome OSR’s recognition of our ambitious approach and the positive level of engagement we have with those they spoke with. From user needs for projections, future population statistics, definitions for migrants, priorities from Census 2021 outputs, we have consulted and will continue to consult to shape our plans.

We continue to work with OSR to make sure we are effectively responding to their feedback and ultimately providing better statistics for our users. As part of our commitment, we will continue to inform users through these blogs and our progress updates on transformation. We’re working towards publishing our future statistical design of migration statistics and how it fits with population statistics in July. As our methods develop, we will regularly consult with external experts to ensure we are providing the best estimates for a wide range of users. We will also continue to be transparent about our methods and the impact of using different data has on the estimates we ultimately publish.

Full steam ahead

Statistical producers from across the Government Statistical Service (GSS) have today set out their strategy to collaborate and improve the coherence and accessibility of migration statistics for users. For example, we have aligned the timing of our publication with Home Office’s latest immigration quarterly statistics, which gives users a more complete picture of who is arriving in and leaving the UK.

We continue to learn about changed behaviours during the pandemic and the impact that has on data sources. Together with more timely data and access to the final census estimates we intend to update our June 2021 estimates in November this year and where data permits, provide estimates up to June 2022. Our revisions policy updated today reflects the nature of continuing to publish the best estimates possible in a timely way.

Going forward, we want to provide population and migration statistics more quickly and more frequently.  Throughout this year we will continue to publish research updates, building towards “experimental” monthly age/sex profiles of the population relating to 2022.

This will start with a proof of concept for admin-based monthly population estimates as soon as possible after the first Census 2021 results are released, using information from health, tax, benefits and education data sources, among others.

As these methods mature, we will embed these into official estimates and move on from the “experimental” status towards National Statistics. This week we have also updated our research on producing admin data-based ethnicity estimates.

While they are not official statistics, they show the progress we have made in being able to produce more regular outputs on ethnicity, down to local authority level.

Providing these regular population insights in the future will allow decision makers to have the most up to date information possible on the dynamics of the population, showing the impact of seasonal patterns of mobility in a timely manner, and ensure that public services can be provided to the right population groups in the right places, at the right time.