Was there a Ferguson Effect on crime rates in large U.S. cities?

Abstract

PurposeThere has been widespread speculation that the events surrounding the shooting death of an unarmed young black man by a white police officer in Ferguson, Missouri—and a string of similar incidents across the country—have led to increases in crime in the United States. This study tested for the “Ferguson Effect” on crime rates in large U.S. cities. MethodsAggregate and disaggregate monthly Part I criminal offense data were gathered 12months before and after August 2014 from police department data requests and websites in 81 large U.S. cities. The exogenous shock of Ferguson was examined using a discontinuous growth model to determine if there was a redirection in seasonality-adjusted crime trends in the months following the Ferguson shooting. ResultsNo evidence was found to support a systematic post-Ferguson change in overall, violent, and property crime trends; however, the disaggregated analyses revealed that robbery rates, declining before Ferguson, increased in the months after Ferguson. Also, there was much greater variation in crime trends in the post-Ferguson era, and select cities did experience increases in homicide. Overall, any Ferguson Effect is constrained largely to cities with historically high levels of violence, a large composition of black residents, and socioeconomic disadvantages. ConclusionsThe national discourse surrounding the “Ferguson Effect” is long on anecdotes and short on data, leaving criminologists largely on the sidelines of a conversation concerning one of the most prominent contemporary issues in criminal justice. Our findings are largely consistent with longstanding criminological knowledge that changes in crime trends are slow and rarely a product of random shocks.