This article compares the average productivity of migrants (who work in a country different from their country of origin) and stayers (whose entire academic career takes place in their country of origin) in a set of 2,530 highly productive economists that work in 2007 in a selection of the top 81 Economics departments worldwide. The main findings are the following two. First, productivity comparisons depend on the cohort and the type of department. For example, in the top U.S. departments, foreigners are more productive than stayers only among older individuals; in the bottom U.S. departments, this is the case for both cohorts, while in the other countries the productivity of foreigners and stayers is indistinguishable for both cohorts. Second, when we restrict our attention to an elite consisting of economists with above average productivity, all productivity differences between migrants and stayers in the United States vanish. As our analysis depends on observational data in which the migration decision is not exogenously identified, our estimates have a descriptive rather than a causal interpretation. However, our results are very robust to the treatment of the elite, the partition into several department categories, and the definition of the cohorts and the productivity notion. (JEL J61)