A new Pew Research Center analysis estimates that at least 3.9 million unauthorized immigrants – and possibly as many as 4.8 million – lived in Europe in 2017. Learn how we conducted the first comprehensive estimate of Europe's unauthorized immigrant population in over a decade.
Pew Research Center conducts polls in many countries other than the United States. But the methodology behind our international surveys can vary from country to country, and what works in one place might not work in another.
The latest Pew Research Center data estimates there were 10.5 million unauthorized immigrants living in the U.S. in 2017, down significantly from a decade prior. In this video, our researchers go behind the scenes to explain the “how” and “why” behind determining these new numbers.