Latin America has the unfortunate distinction of being the most violent, murderous region in the world, accounting for 9% of the world’s population but 33% of its homicides (Jaitman et al., 2015). The countries of the Northern Triangle – El Salvador, Guatemala, and Honduras – are among the most violent in the region. Violence, particularly lethal violence, imposes enormous social and economic burdens on the region. In the Northern Triangle, the costs are truly staggering, with one studying estimating the economic costs of violence for El Salvador, Guatemala, and Honduras at 7.5%, 5.4%, and 7.2% of gross domestic product respectively (Jaitman et al., 2015). With an average homicide rate of 51 per 100,000 inhabits per year (Igarape, 2015), the Northern Triangle is in the midst of a violence epidemic according to international standards.

Despite the overwhelming urgency of the issue, the phenomenon of violence remains poorly understood in the Northern Triangle. The problem is not simply a lack of knowledge – although major gaps remain – it is that current knowledge, particularly evidence derived from rigorous research and evaluations– is not accessible to policymakers in the region in a readily usable and understandable format.

In this systematic meta-review, we summarize and analyze evidence concerning a vast array of programmatic interventions in order to better inform policies to reduce violence in the region. Specifically, this report is based on three research components:

1. A systematic meta-review, or review of reviews, of systematic reviews and meta-analyses considering causal evidence relating to violence reduction;
2. A supplemental review considering materials beyond the scope of the meta-review in order to enhance and provide further context for its findings; and
3. A field study employing semi-structured interviews and site visits to offer additional guidance regarding implementation and adaptation.

This report may be the first of its kind – “To date, no meta-reviews have included the full range of programs that are intended to prevent youth violence; additionally, no meta-reviews have used both quantitative and qualitative approaches” (Matjasko et al., 2012).4 Our goal is provide policy recommendations informed by rigorous evidence but grounded in the practical realities of implementation in real-world settings.