What kinds of interventions are most effective in reducing community violence, the every-day street violence that rarely makes headlines—but often accounts for more homicides than other forms of violence?
In what may be a first-of-its kind study, we conducted a systematic meta-review, synthesizing evidence from 43 reviews covering over 1,400 individual studies, visited over 20 sites, and conducted over 50 semi-structured interviews to answer the question, at the request of the U.S. Agency for International Development (USAID).
The motivating factor for the USAID study was Latin America, which has the unfortunate distinction of being the most murderously violent region in the world, accounting for nine percent of the world’s population but 33 percent of its homicides. Of particular concern to the study sponsors were El Salvador, Guatemala and Honduras –the countries of the so-called Northern Triangle—which statistics suggest are the deadliest centers of violence.
With an average homicide rate of 51 per 100,000 inhabits per year, the Northern Triangle is in the midst of what, by international standards, can only be deemed a violence epidemic.
Violence in the Northern Triangle region remains relatively poorly understood. The problem is not simply a lack of knowledge, although significant gaps remain. Current knowledge, especially from the most reliable experimental and quasi-experimental evaluations, is often inaccessible to policymakers in readily usable formats.
Our conclusions, based on the report we produced last month, suggest effective approaches that Latin American policymakers could take. But we believe they also have wider implications.
To our knowledge, no study on community violence has combined quantitative and qualitative approaches to provide recommendations based on both rigorous evidence and practical realities.
The results of our examinations of violence-reduction strategies, most of them in the U.S., were intriguing. We found that a few programmatic interventions, such as focused deterrence and cognitive behavioral therapy, exhibited moderate to strong effects on violence and were supported by substantial evidence.
Focusing on the most successful approaches, we identified the following six shared “elements of effectiveness:
- Specificity: maintaining a specific focus on those most at risk for violence;
- Proactivity: being proactive to prevent violence before it occurs;
- Legitimacy: increasing the perceived and actual legitimacy of institutions and strategies;
- Capacity: careful attention to program implementation;
- Theory: having and following a well-defined theory of change; and
- Partnership: active engagement and partnership with critical stakeholders.
We also learned that a defining characteristic of violence is “stickiness,” meaning it clusters tightly in and around a small number of places, people, and behaviors.
For instance, in Boston, one percent of youth aged 15-24 were responsible for over 50 percent of city-wide shootings, and 70 percent of total shootings over a three-decade period were concentrated in just five percent of the city.
Similarly, in the Venezuelan capital of Caracas, 80 percent of the homicides in one community—Sucre—came from just six percent of its street blocks.
Not surprisingly, programmatic interventions that target these clusters are generally more effective than those that do not. This is true across the policy spectrum, from policing to prevention. In public health terms, interventions that work with indicated and selected populations are usually more effective than universal ones, with tertiary and secondary prevention strategies more successful than primary ones.
Focusing attention on high-risk places, people and behaviors will fail if violence is displaced or simply “moves around the corner.” Fortunately, a robust body of evidence clearly establishes that when crime and violence are targeted, displacement is minimal and the impact to surrounding areas is likely to be positive.
(That said, it’s equally clear that organized crime is more capable of relocating or otherwise responding to targeted interventions.)
Given the modest effects of most interventions, that violence generally clusters around a small number of places, people and behaviors, and that violence is not displaced from those clusters when they are targeted, we reached the simple yet powerful conclusion that it is advisable to concentrate and coordinate anti-violence efforts where they matter most.
Concentrating efforts is intuitive, backed by strong evidence, and perhaps most importantly, feasible as a matter of politics and budgets. Public and private institutions that respond to violence lack the capacity to be everywhere; but they can be where it matters most.
It’s important to openly acknowledge a limitation of our work: The reviews and studies we examined came overwhelmingly from high-income countries, especially the U.S. Our fieldwork suggests that these findings still have relevance to the Northern Triangle and Latin America generally. But we must be mindful that there are limits to the validity of evidence generated in one setting and then applied in another.
Based on our meta-review and fieldwork, we offered four recommendations to governmental and non-governmental funders seeking to reduce community violence:
- Recognize the centrality of reducing violence to poverty reduction and development by creating space within portfolios where violence is the exclusive, or at least primary, concern.
- Within that space, align activities and investments with the evidence in an incremental but purposeful manner. Before adoption, evidence-informed strategies should be filtered through a deliberate process of customization in consultation with local stakeholders.
- Build internal and external expertise for evidence-informed violence reduction, with an emphasis on research and analysis.
- Launch coordinated regional research efforts that emphasize coordinated approaches, consistent methodologies, and the cumulative development of knowledge.
High rates of violence are not inevitable in the Northern Triangle, nor anywhere else for that matter. With careful attention to the evidence, hard work, and a collaborative mindset, peace is possible.
Thomas Abt, a Senior Research Fellow with the Harvard Kennedy School of Government, has served as Deputy Secretary for Public Safety for the State of New York and as Chief of Staff to the Department of Justice Office of Justice Programs. Christopher Winship is the Diker-Tishman Professor of Sociology and a senior faculty member at the Harvard Kennedy School of Government. They welcome comments from readers.