Facebook helps show number of migrants underestimated in the UK

10 November 2021

Facebook has helped a University of Oxford researcher reveal the number of European migrants in the UK has been underestimated, according to research just published in the journal, Demography.

Currently, official migration statistics are collected and reported by the Office of National Statistics. But the new study, by Francesco Rampazzo from the Leverhulme Centre for Demographic Science, used other materials, including the social media platform to reveal that, in 2018, there were likely to have been 25% more European migrants in the UK than official Office of National Statistics figures suggested and, in 2019, there may have been an additional 20%.

The demographer, who worked in collaboration with a team from the University of Southampton, examined data from a range of sources, including the Facebook Advertising Platform, the Labour Force Survey (LFS), and country-specific information, to provide a more accurate picture. He says, ‘In 2019, on ONS figures there were an estimated 3.6 million European migrants in the UK. But this research suggests the real figure was more likely to be around four million.’

He explains, ‘Calculating migration is always going to be complicated. But the reason for the underestimate is the lack of quality of the official migration data. What is striking is our study reveals the underestimate is big. This is important because decisions-makers require accurate evidence-based information to produce effective policies that affect people’s lives.

Knowing the number of migrants in a region is important for planning….for example for schools and transport. The COVID-19 pandemic has demonstrated the importance of knowing the number of residents in the UK for producing reliable estimates of vaccinated people.

The ONS is aware of an undercount of 16% for net migration to the UK from eight EU countries in 2016. Currently, the UK uses a survey-based system to collect migration information and relies heavily on the International Passenger Survey (IPS), created in 1961 and which the ONS admits ‘has been stretched beyond its original purpose’.
In comparison, this latest research combines statistics from the Facebook Advertising Platform, the Labour Force Survey, and unemployment and GDP (Gross Domestic Product) figures from each of the 20 countries included in the study.

‘We looked at unemployment and GDP figures for each country to better understand the push and pull factors of migration. Why migrants might move away from their home country or return to it,’ Francesco explains.

According to the researcher, ‘It is important to use a combination of different data sources and not rely on similar types...The hope is that this research contributes to a learning process and demonstrates a way to produce and more accurate understanding on the complex issue of international migration.’

Notes for Editors

For further information and enquiries, please contact news.office@admin.ox.ac.uk.

The paper can be seen here https://doi.org/10.1215/00703370-9578562

The Facebook Advertising Platform is set up to provide advertisers with information on the age, sex, language, and real time location data of its users.
It can tell where users are accessing the platform, the country they came from, and defines a migrant as a person that used to live in country x and now lives in country y. The Labour Force Survey measures the inflows and outflows of international migrants and collects data every three months. However, migrants tend to come and go - or at least that was the case before the pandemic.

The countries included in the study are Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, the Netherlands, Poland, Portugal, Romania, Slovakia, Spain, and Sweden.

It collected information from the Facebook Advertising Platform in the third week of July 2018 and in July in 2019. Data from the Labour Force Survey was provided by the ONS for the period of June-July 2018 and June-July 2019.

The research was a collaboration between the University of Oxford, the Centre for Population Change at the University of Southampton, the University of Trento, the Qatar Computing Research Institute, and the Max Planck Institute for Demographic Research.

Leverhulme Centre for Demographic Science
The Leverhulme Centre for Demographic Science (LCDS) was set up in 2019 to build an internationally recognized and interdisciplinary centre of demographic science that will disrupt, realign and raise the value of demography in science and society. For more information about the Trust, please visit www.leverhulme.ac.uk and follow the Trust on Twitter @LeverhulmeTrust

The University of Oxford
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