Black Lives Matter’s Effect on Police Lethal Use-of-Force∗ Travis Campbell† December 29, 2020 Abstract Has Black Lives Matter influenced police lethal use-of-force? A difference-in- differences design finds census places with Black Lives Matter protests experience a 15% to 20% decrease in police homicides over the ensuing five years, around 300 fewer deaths. The gap in lethal use-of-force between places with and without protests widens over these subsequent years and is most prominent when protests are large or frequent. This result holds for alternative specifications, estimators, police homicide datasets, and population screens; however, it does not hold if lethal use-of-force is normalized by violent crime or arrests. Protests also influence local police agencies, which may explain the reduction. Agencies with local protests become more likely to obtain body-cameras, expand community policing, receive a larger operating budget, and reduce the number of property crime-related arrests, but forego some black officer employment and college education requirements. JEL Codes: K42, Z13, D74, Keywords: Black Lives Matter, Police, Law and Economics, Police Homicides, Lethal Use-of-force, Law Enforcement ∗I am grateful to Lee Badgett, Deepankar Basu, Ina Ganguli, Kathryne Young and the participants of the 2019 Umass/New School graduate student workshop for helpful feedback on earlier drafts of this paper. All errors remain my own. †Department of Economics, University of Massachusetts Amherst, 105 Gordon Hall, 412 North Pleasant Street, Amherst, MA 01002. For correspondence, email:
[email protected]. 1. Introduction Reacting to the acquittal of George Zimmerman for the killing of Trayvon Martin in 2013, Alicia Garza posted her reaction to Facebook: “black people.