This report was commissioned by the U.S. Agency for International Development (USAID) for the Central America Regional Security Initiative (CARSI), a United States government effort primarily executed by both USAID and the U.S. Department of State Bureau of International Narcotics and Law Enforcement Affairs (INL). In preparation for this report, the authors performed a systematic meta-review of 43 reviews, including over 1,400 studies, to identify what works in reducing community violence. In addition, they supplemented their findings with fieldwork in El Salvador, Guatemala, Honduras, and the United States, visiting over 20 sites and conducting over 50 semi-structured interviews.
The authors found that a few interventions, such as focused deterrence and cognitive behavioral therapy, exhibited moderate to strong effects on crime and violence and were supported by substantial evidence. They identified six “elements of effectiveness” shared by the most impactful interventions, including maintaining a specific focus on those most at risk for violence; proactive efforts to prevent violence before it occurs whenever possible; increasing the perceived and actual legitimacy of strategies and institutions; careful attention to program implementation and fidelity; a well-defined and understood theory of change; and active engagement and partnership with critical stakeholders.