The proportion of foreign-born people in rich countries has tripled since 1960, and the emigration of high-skilled people from poor countries has accelerated. Many countries intensify their efforts to attract and retain foreign students, which increases the risk of brain drain in the sending...

This paper reviews the existing literature on the impact of migrants networks on the patterns of international migration. It covers the theoretical channels at stake in the global effect of the networks. It identifies the key issues, namely the impact on size, selection and concentration of the...