Alberto Alesina of Harvard University talks with EconTalk host Russ Roberts about how people in the US and five European countries perceive the population and characteristics of legal immigrants. Reporting on research with Armando Miano and Stefanie Stantcheva, Alesina finds that individuals systematically overestimate the number of immigrants while underestimating their standard of living. His research also finds that support for welfare payments to the poor is related to the perception people have of the size of the immigrant population and their economic status. The conversation concludes with a discussion of why people's perceptions are so inaccurate and the implications of perception for public policy.