The fire-armed police effect: evidences from a quasi-natural experiment in Brazil

Abstract

We estimate the impact of fire-armed police on violent crimes (homicides and acts of aggression) in a quasi-natural experiment in Brazil. In 2003, Brazilian legislators approved a law that regulates the use of firearms by the municipal police. We explore the population eligibility criterion as an instrumental variable of firearm possession in a linear regression discontinuity design. We find robust results that a municipal police force with firearms significantly reduces homicides and acts of aggression between 2002 and 2012. Moreover, we find suggestive evidence of more arrests, the incapacitation of criminals, and absence of deterrence.