移民如何促进出口？

How do immigrants promote exports? To answer this question we propose an empirical framework allowing to disentangle the role of migration networks that operate at a bilateral level from that of productivity channels (knowledge diffusion and increased workforce diversity) that operate at the aggregate level. We find evidence supporting both, at the extensive as well as at the intensive margin. The results are robust to using various IV strategies. While richer countries’ exports tend to benefit more from immigrants’ diversity (especially in sectors characterized by complex production processes), developing countries benefit from knowledge diffusion more. • Immigration has the potential to make host countries more productive, especially in sectors in which immigrants bring with them productive skills and knowledge from their home countries that supplement and complement local factors. • Migration-induced productivity shifts combined to lower transaction costs generated through the web of networks linking immigrants to their home countries materialize in the form of a better export performance. • We use a standard gravity model to test the transaction cost channel, and exporter–sector–year aggregated estimations to test the knowledge diffusion and birthplace diversity channels. We show that all three channels are at play.