Public Health Interventions and Economic Growth: Revisiting The Spanish Flu Evidence

Using data from 43 US cities, Correia, Luck, and Verner (2020) finds that the 1918 Flu pandemic decreased economic growth, but that Non Pharmaceutical Interventions (NPIs) mitigated its adverse economic effects. Their starting point is a striking positive correlation between 1914-1919 economic growth and the extent of NPIs adopted at the city level. We show that those results are driven by population growth between 1910 to 1917, before the pandemic. We also extend their difference in differences analysis to earlier periods, and find that once we account for pre-existing differential trends, the estimated effect of NPIs on economic growth are a noisy zero; we can neither rule out substantial positive nor negative effects of NPIs on employment growth.