Foreign ideas steer U.S. innovation

Using a genealogy of 13 million patents (1887–2024), the authors trace which earlier, foreign technologies appear as inputs to new U.S. inventions and show that counties with historical migrant ties to a given origin adopt that origin's technologies and then invent more in those areas. The effect is causal (migration settlement used as an instrument), shapes the direction of technical change, and persists in local labor markets decades later. — If foreign knowledge is a causal driver of domestic innovation, immigration, international collaboration, and regional R&D policy are not just social or moral issues but strategic levers for national technological strength.