Andrea Morrison, Sergio Petralia, and Dario Diodato (2018), /Journal of Economic Geography Vol.22(2)
More than 30 million people migrated to the US between the 1850s and 1920s. In the order of thousands became inventors and patentees. Drawing on an original dataset of immigrant inventors to the US, we assess the city-level impact of immigrants patenting and their potential crowding out effects on US native inventors. Our study contributes to the different strands of literature in economics, innovation studies and economic geography on the role of immigrants as carriers of knowledge. Our results show that immigrants’ patenting is positively associated with total patenting. We find also that immigrant inventors crowd-in US inventors. The growth in US inventors’ productivity can be explained also in terms of knowledge spill-overs generated by immigrants. Our findings are robust to several checks and to the implementation of an instrumental variable strategy.