National Statistical

Measuring migration is complex, with different data sources measuring different aspects of it.  Here Jay Lindop explains what the latest data shows and the work ONS is doing to understand how different data sources align.

It has been well documented that we’re transforming the way the Office for National Statistics produces population and migration estimates, to better meet the needs of our users, with the aim of putting administrative data at the core of our evidence on international migration (UK) and on population (England and Wales) by the summer of 2020.

We’ve been using additional datasets from the Home Office, Higher Education Statistics Agency and Department for Work and Pensions to develop our migration estimates, alongside evidence from the International Passenger Survey (IPS), to ensure we use the best evidence to report on the movement into and out of the country.

What the data shows

Our latest quarterly analysis of the available data suggests that long-term net migration, immigration and emigration figures have continued to remain broadly stable since the end of 2016.

Digging a little deeper, you can see EU long-term immigration has fallen since 2016 and is at its lowest since 2013. Meanwhile, non-EU long-term immigration has gradually increased over the last five years to similar levels seen in 2011.

Today’s data also shows that since 2016, the pattern of migration to the UK for work has been changing. Long-term immigration to the UK for work has fallen, mainly driven by the decline in EU arrivals. Despite this, 99,000 EU citizens still came to the UK long-term to work in 2018, a level similar to 2012. We are also seeing the number of skilled work visas for non-EU citizens increasing, although overall non-EU work-related immigration has remained broadly stable.

Of course, decisions to migrate are complex and a person’s decision to move to or from the UK will always be influenced by a range of social and economic factors.

Different patterns from different sources

As well as developing our migration estimates, we are also aware that our users are interested in how many people actually reside in the UK at any point in time and the impact that they have while here.

Therefore, alongside the quarterly analysis, we’ve also released our short-term international migration data for mid-2017 and the latest population of the UK by country of birth and nationality estimates. The latter uses the Annual Population Survey (APS) which, while not designed to measure long-term international migration (LTIM), does give insights into changes in our population.

In theory the change in the number of non-UK born people living in the UK from year-to-year should be close to the net flow of non-UK born people into the UK. However, the IPS and APS are designed to measure different aspects of migration, in different ways, based on different types of data, and neither has complete coverage. While for overall migration the long-term trends are similar, the APS has shown different patterns to LTIM for changes in EU and non-EU migration. The most recent figures for overall migration are also further apart than we have seen previously.

This change is something we are aware of and are investigating, as we set out in our workplan which we published in February.

The future

As we progress with our recently published workplan we will make more detailed comparisons between sources, and look at how survey design, sample sizes and response patterns influence the results. We will aim to complete this work as soon as we can – we will be publishing a progress report next month and more detailed findings later this summer – to help us better understand trends in migration from all sources, feed into our reporting and our transformation programme.

The work is important as we still plan to use the IPS as a key indicator of the trends in migration even when we have other data sources available, and we therefore need to understand how the current data sources align.