Why U.S. Immigration Barriers Matter for the Global Advancement of Science

This paper studies the impact of U.S. immigration barriers on global knowledge production. We present four key findings. First, among Nobel Prize winners and Fields Medalists, migrants to play a central role in network— representing 20-33% frontier producers. Second, using novel survey data hand-curated life-histories International Math Olympiad (IMO) medalists, we show that are up six times more productive than other countries—even after accounting for talent during one's teenage years. Third, financing costs factor preventing foreign from migrating abroad pursue their dream careers, particularly developing countries. Fourth, certain 'push' incentives reduce – by addressing constraints top could increase scientific output future cohorts 42% percent. conclude discussing policy options community.