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,...

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...

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,...

Field experiments rely heavily on self-reported data, but subjects may misreport behaviors, especially sensitive ones such as crime. If treatment influences survey responses, it biases experimental estimates. We develop a validation technique that uses intensive qualitative work to assess survey...

In most societies, a small number of people commit the most serious violence. Short-term studies have shown that cognitive behavioral therapy (CBT) can reduce such antisocial behaviors. These behavior changes may be temporary, however, especially from therapy on its own. This is unsettled,...