In this chapter we present new evidence on the effects of police programs against illegal gun carrying that draws on data from Pittsburgh, Pennsylvania. As with all nonexperimental policy evaluations, identifying causal program effects is difficult. However, several features of Pittsburgh’s 1998 policing program offer a unique opportunity to isolate the impact of the police patrols from the effects of other confounding factors that cause crime rates to vary across areas and over time.
Jacqueline Cohen and Jens Ludwig
In Evaluating Gun Policy: Effects on Crime and Violence, Brooking, 2003