Migrant Inventors and the Technological Advantage of Nations

German and Austrian Jewish scientists who fled Nazi Germany in the 1930s famously boosted American innovation in chemistry—their fields of expertise. But does this pattern generalize? This paper investigates whether migrant inventors systematically help their receiving countries develop patenting capabilities in the same technologies where their home countries specialize.

Using patent data across 651 technology subclasses for 95 countries over two decades (1990-2010), combined with bilateral inventor migration data, we measure technological specialization using Revealed Technological Advantage (RTA). We examine both 'take-offs'—countries gaining advantage in entirely new technologies—and growth in technologies where they already have some activity. The results are striking: a small number of immigrant inventors can significantly reshape a country's innovation portfolio.

To establish causality, we employ two instrumental variable strategies: 30-year-old historical migration networks and predicted inventor flows based on push-pull factors. Multiple falsification tests—including randomizing inventor nationalities and examining inventors from countries without technological advantage—confirm that our results are driven by actual inventor presence transferring technology-specific knowledge, not pre-existing trends or spurious correlations.