As in many cities, gangs in Medellín provide order and collect 'taxes'. Why do gangs govern civilians? Some argue that criminal and state rule are substitutes. Hence, increasing state presence should crowd out gangs. But they could also be complements. States produce growth and general demand...

Medellin's government wanted to raise its efficacy, legitimacy, and control. The city identified 80 neighborhoods with weak state presence and competing armed actors. In half, they increased non-police street presence tenfold for two years, offering social services and dispute resolution. In...

Gangs govern millions worldwide. Why rule? And how do they respond to states? Many argue that criminal rule provides protection when states do not, and that increasing state services could crowd gangs out. We began by interviewing leaders from 30 criminal groups in Medellin. The conventional...

In 2016 the city of Bogotá doubled police patrols and intensified city services on high-crime streets. They did so based on a policy and criminological consensus that such place-based programs not only decrease crime, but also have positive spillovers to nearby streets. To test this, we worked...

Cities target police patrols and public services to control crime. What are the direct and spillover effects of such targeted state services? In 2016 the city of Bogotá, Colombia, experimented on an unprecedented scale. They randomly assigned 1,919 streets to either 8 months of doubled police...

For citizens across Latin America, basic order is provided by local criminal organizations. Existing studies establish that criminal governance is pervasive, persistent, and consequential --- not only for those governed but for macro-level political, social, and economic outcomes. Yet systematic...

The paper shows that self-control, time preferences, and values are malleable in adults, and that investments in these skills and preferences reduce crime and violence. The authors recruited criminally-engaged Liberian men and randomized half to eight weeks of group cognitive behavioral therapy,...

Can cash transfers promote employment and reduce poverty in rural Africa? Will lower youth unemployment and poverty reduce the risk of social instability? The authors experimentally evaluate one of Uganda's largest development programs, which provided thousands of young people nearly...