The Effect of Stay-at-Home Orders on COVID-19 Infections in the United States

James H. Fowler; Seth J. Hill; Nick Obradovich; Remy Levin

The time and date of county-level "stay-at-home" or "shelter-in-place" orders for each state and locality were aggregated and reported on a web page maintained by the New York Times starting on March 24, 2020. 16 As new orders went into effect, this page was updated. We checked it once daily to update the data through April 17, 2020. In some cases a statewide order was reported with reference to earlier city-level or county-level orders in the state without specifying where they occurred. In those cases, we searched local news outlets to find references to official city and county orders in the state that preceded the statewide order. For each county in each state we recorded the earliest time and date that a city, county, or statewide order came into effect. Figure 1a shows the distribution of order dates. As of April 17, 2020, 18 states (1,451 counties) exhibited county-level variation in order dates, 27 states and the District of Columbia had statewide orders with no local variation (1,307 counties) and 5 states (386 counties) had no order in place.