Police crackdowns on illegal gun carrying: a systematic review of their impact on gun crime

This paper presents a systematic review of the impact of police strategies to reduce illegal possession and carrying of firearms on gun crime, including directed patrols, monitoring of probationers and parolees, weapon reporting hotlines, and others. Four studies met the inclusion criteria, reporting a total of seven nonrandomized tests of directed patrols focused on gun carrying in three American cities (five tests) and two Colombian cities (two tests). Six of the seven tests (not all of which were independent) suggest that directed patrols reduced gun crime in high-crime places at high-risk times. However, conclusions and generalizations must be qualified based on the small number of studies, variability in study design and analytic strategy across the studies, preintervention differences between intervention and comparison areas, and limited data regarding factors such as implementation, crime displacement, and long-term impact.Although the protocol for this review was registered and approved by the Campbell Collaboration Crime and Justice Group (), this paper represents an independent effort of the authors and has not been reviewed by the Campbell Collaboration. Evan Mayo-Wilson conducted research for this project while he was Coordinator of the Campbell Crime and Justice Group at the University of Pennsylvania's Jerry Lee Center of Criminology and a student at the Fels Institute of Government.