Between 1883 and 1919, Andrew Carnegie funded the construction of more than 1,500 public libraries across the United States, reducing the costs of accessing knowledge for millions. We study the effect of these libraries on innovation. Patenting in recipient places increased on average by 10%–12% in the 20 years following library construction relative to a novel control group of cities that applied for but did not build libraries. We show that access to scientific knowledge and increased collaboration opportunities are possible mechanisms.

During the 1918–1919 influenza pandemic, many local authorities made the controversial decision to close schools. We use newly digitized data from newspaper archives on the length of school closures for 165 large U.S. cities during the 1918–1919 flu pandemic to assess the long-run consequences of closing schools on children. We find that the closures had no detectable impact on children's school attendance in 1920, nor on their educational attainment and adult labor market outcomes in 1940. We highlight important differences between the 1918–1919 and COVID-19 pandemics and caution against extrapolating from our null effects to modern-day settings.