More than numbers: first global dataset shows who is immigrating

International migration is becoming an increasingly important driver of population change, yet surprisingly little is known about the characteristics of the people moving between countries. Existing global migration data largely tell us how many people migrate, but provide a less complete picture of their age and educational background.

In their study published in Scientific Data, IIASA researchers Dilek Yildiz and Guy Abel  addressed this gap by estimating the age and educational composition of male and female immigration flows for 199 countries across six five-year periods, from 1990–1995 to 2015–2020. Both researchers are also affiliated with the Wittgenstein Centre for Demography and Global Human Capital, a research collaboration between IIASA, the Austrian Academy of Sciences, and the University of Vienna.

“Knowing how many people migrate only tells us part of the story. Age and education matter enormously for understanding how migration reshapes populations and the distribution of skills between countries. The dataset gives us a much clearer picture of who is arriving and how that has changed over time,” explains Yildiz, lead author and a researcher in the IIASA Population and Just Societies Program.

Using census samples from 74 countries and a machine-learning approach known as super learning, the researchers estimated immigration compositions across countries and periods where comparable data have previously been unavailable.

The results show that the share of immigration flows made up of people with higher education has increased across all world regions, while Europe has the highest proportion of immigrants with secondary or higher education. The researchers also found that men and women immigrating to the same country tend to be similar in terms of age and education, while much larger differences emerge when comparing immigration patterns across countries.

Importantly, the dataset captures the composition of flows – who arrives and when – rather than migrant stocks, which provide a snapshot of who is living in a country at a particular point in time. This allows researchers to examine brain gain and brain drain more precisely, including whether skilled immigration is accelerating and which age groups are driving these changes.

More detailed information about migration flows can also strengthen population projections. These projections underpin decisions about future education and healthcare needs, labor markets, and other public services, making a better understanding of the people moving into countries directly relevant to long-term policy planning.

“Understanding how migration changes the age and skills profile of populations is essential for planning ahead. Better information on these flows can help policymakers assess the effects of migration policies, anticipate changes in the workforce, and plan more effectively for future population needs,” concludes Guy Abel, study coauthor and researcher in the IIASA Population and Just Societies Program who is also affiliated with the University of Hong Kong.

Reference

Yildiz, D., Abel, G. (2026) A global dataset of immigration flow composition by age, sex and educational attainment Scientific Data DOI: doi.org/10.1038/s41597-026-07969-8