How the Other Half Died: Immigration and Mortality in U.S. Cities.

This article examines how the implementation of country-specific immigration quotas in the 1920s United States affected urban mortality rates, particularly deaths from infectious diseases. Using annual cause-of-death data from 348 U.S. cities between 1900 and 1937, the study finds that cities with larger quota-induced reductions in immigration experienced significant and persistent declines in mortality, driven mainly by reduced residential crowding and improved public health conditions. The analysis distinguishes these effects from mere compositional changes in population, showing substantial spillover benefits to U.S.-born residents, including African Americans, and highlights that overcrowding in housing and healthcare facilities was a key mechanism linking immigration restrictions to mortality declines. Alternative explanations such as contagion from immigrant arrivals, labor market shifts, and public health spending changes were found to be less influential. The findings suggest that better-managed urban housing and public health policies could mitigate infectious disease spread without resorting to restrictive immigration measures.