Most countries in the periphery specialized in the export of just a handful of primary products for most of their history. Some of these commodities have been more volatile than others, and those with more volatile prices have grown slowly relative both to the industrial leaders and to other...

The contending fundamental determinants of growth -- institutions, geography and culture --exhibit far more persistence than do the growth rates they are supposed to explain. So, what exogenous shocks might account for the variance around those persistent fundamentals? The terms of trade seems...

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,...

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...

Gun violence is the most pressing public safety problem in American cities. We report results from a randomized controlled trial (N=2,456) of a community-researcher partnership--the Rapid Employment and Development Initiative (READI Chicago)--which provided 18 months of a supported job alongside...

Questions about current and prior religion adherence from the International Social Survey Program and the World Values Survey allow us to calculate country-level religious-conversion rates for 40 countries. These conversion rates apply to religion adherence classified into eight major types. In...

When local cost discovery generates knowledge spillovers, specialization patterns become partly indeterminate and the mix of goods that a country produces may have important implications for economic growth. We demonstrate this proposition formally and adduce some empirical support for it. We...

We study two interventions for underemployed youth across five Ethiopian sites: a $300 grant to spur self-employment, and a job offer to an industrial firm. Despite significant impacts on occupational choice, income, and health in the first year, after five years we see nearly complete...

Policymakers can take actions to prevent local conflict before it begins, if such violence can be accurately predicted. We examine the two countries with the richest available sub-national data: Colombia and Indonesia. We assemble two decades of fine-grained violence data by type, alongside...