Providing the best picture of international migration

The Office for National Statistics has been transforming its international migration statistics using a range of new and existing data sources. Better use of data held across government will underpin the future of the UK’s migration statistics. Jay Lindop explains why the latest estimates will be the last to use the International Passenger Survey and why today’s figures reinforce the need to progress the move to a new system.

Historically, migration estimates have been based on the International Passenger Survey, carried out at ports and airports. However, we’ve long acknowledged that the IPS has been stretched beyond its original purpose and that we need to use all available data to fully understand international migration in an increasingly complex world.

Travel restrictions, enforced across the world, have affected travel to and from the UK since the turn of the year. They have also affected the ONS’ face-to-face survey operation, with the suspension of IPS on 16 March 2020 and no current date for re-commencing to measure tourism and its value which was the purpose for which it was originally designed.

We will be delivering new measures of migration based on administrative data from November 2020 onwards. Therefore, this is last MSQR using the IPS for headline estimates.

What does the data show?

In the year ending March 2020, around 313,000 more people moved to the UK, intending to stay for 12 months or more than left the UK (net migration, the balance between immigration and emigration)

Over the year, around 715,000 people moved to the UK (immigration) and around 403,000 people left the UK (emigration). The increase in immigration and net migration is being driven by an increase in non-EU nationals arriving in the UK for study reasons.

While collecting data for the 2020 Q1 International Passenger Survey (IPS), there was an overestimation in the number of non-EU students, particularly students coming from Asia. While this trend of increasing non-EU student migration was backed up by Home Office Visa data, the scale of the rise was not.

From previous analysis we know that the IPS is more susceptible to sampling variability for students as most arrive in clusters, often at the start of academic terms for new courses.

Making use of all available data sources

In line with existing transformation work, and to account for the unexpected large rise in IPS figures most likely due to sampling variability, we used Home Office visa data to adjust the long term international migration non-EU immigration figures. In doing so we drew on our experience in 2017 and 2018 of monitoring, adjusting and ultimately revising student migration figures following an unexpected decrease in the number of non-EU citizens coming the UK to study seen in 2016. Subsequent analysis suggested the sample missed some students and was revised accordingly in February 2019.

We believe that our figures with the adjustment provides the best current estimate of long term international migration based on all sources.

Comparability with other sources

The most recent labour market figures  showed a big drop in EU and non-EU nationals working. Sectors like hospitality have been hugely affected, and that is where you find a disproportionate number of non-UK workers. However, we must urge caution in comparing LFS findings to international migration numbers. We have been clear you can’t use employment data for migration estimates.

Firstly, the labour market figures are looking at what was happening at the height of the pandemic – in the months April to June. The most recent MSQR data are for January to March. The LFS also includes short-term and seasonal workers.

As a response to the COVID-19 pandemic, the LFS has also recently moved from the first contact being a face-to-face household based survey to become an entirely telephone based survey. Households such as rental accommodation or those occupied by young people, are less likely to have a landline and may be under represented in the LFS. As the non-UK population contains a higher proportion of young people and those living in rented accommodation, LFS data may underestimate the size of the non-UK population.

The future

We won’t have further IPS data for migration and this recent update provides detail on how better use of data held across government will underpin migration statistics in the future. This MSQR is therefore the final report we will publish using it for our headline estimates.

Now is the right time to focus our efforts on harnessing the power of administrative data for public good, building on the good progress already made through our population and migration transformation programme working alongside statisticians in other government departments.

There is lots of data out there and we are working through accessibility requirements. What is clear is that November’s MSQR will not be an MSQR as you know it. We are on a journey and that will be clearer in January when the government’s new immigration system is in place. But, over time, bringing this data together will give us a richer and deeper understanding of migration and new insights on how our population is changing.

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