Gangs are not simply a law-enforcement problem.  The propensity to become a gang member among youths may develop in response to their interactions with local institutions.  Gangs may also be structured to obtain a competitive advantage in poor or unstable communities.  As such, gangs and gang violence are a problem that should be addressed at the community and societal levels.  However, most gang reduction programs and gang research focus on the individual process of gang participation or school-based gang prevention efforts.  The community context of gangs or gang reduction has rarely been a central focus of policy debate.  Further, there exists little research on the effectiveness of community-based gang violence reduction strategies. High-quality causal analysis on program effectiveness is even scarcer.

The main purpose of this paper is to promote this much-needed domain of research and policy evaluation.  In particular, we assess the impact of a highly publicized community-based approach to mitigate the risk of gang violence, Summer Night Lights (SNL) in the City of Los Angeles.  The SNL Program was designed to mobilize local residents and community groups to raise gang awareness and engage in proactive peace-keeping by providing free meals and activities in selected parks throughout the city.  While the media has highlighted a series of shooting incidents in SNL neighborhoods, city officials report considerable percentage reductions in gang violence.  Further, the SNL Program has continuously expanded annually since 2008, as have donations from foundations and corporations to fund the Program.

Based on a matched case-control design, this study exploits the selective implementation of SNL that operated four nights a week in summer months. We employ a difference-in-difference-in-differences estimator to assess the program’s impact on public safety.  Results indicate that SNL Program led to less visible but potentially important benefits through enhanced community cohesion, such as higher rates of reporting violent crime to law enforcement.  We also discuss lessons from cost-benefit simulation models that shed light to policy implications for those seeking ways to reduce gang violence through enhanced gang awareness and community cohesion.