Does scientist immigration harm US science? An examination of the knowledge spillover channel

The recruitment of foreign-trained scientists enhances US science through an expanded workforce but could also cause harm by displacing better connected domestically-trained scientists, thereby reducing localized knowledge spillovers. We develop a model in which a sufficient condition for the absence of overall harm is that foreign-trained scientists generate at least the same level of localized spillovers as the domestically-trained scientists they displace. To test this condition, we conduct a hypothetical experiment in which each foreign-trained displaces an appropriately matched domestically-trained scientist. Overall, we do not find evidence that foreign-trained scientists harm US science by crowding out better-connected domestically-trained scientists, measured by citations by the US scientific community to their publications.