We analyze a unique data set detailing the financial activities of a drug-selling street gang on a monthly basis over a four-year period in the recent past. The data, originally compiled by the gang leader to aid in managing the organization, contain detailed information on both the sources of...

Why does illegal trade often flourish without formal enforcement, but sometimes fail? Why do illegal trade-reducing policies often fail? Why do States often appear to tolerate illegal trade? A model of trade with cops and robbers provides answers. `Safety in numbers' is a key element: the...

We present a simple model of the effects of hate crime legislation. It shows that even if the direct harm to victims of hate crime is the same as for other crimes, because of other differences in the effects it may still be optimal to exert more law-enforcement effort to deter or prevent hate...

The deterrence of crime and its reduction through incapacitation are studied in a simple multiperiod model of crime and law enforcement. Optimal imprisonment sanctions and the optimal probability of sanctions are determined. A point of emphasis is that the incapacitation of individuals is often...

This paper investigates the impact of economics conditions (carrots) and sanctions (sticks) on murder, assault, robbery, burglary and motor vehicle theft in New York City, using monthly time-series data spanning 1974-1999. Carrots are measured by the unemployment rate and the real minimum wage;...

The prison time actually served by a convicted criminal depends to a significant degree on decisions made by the state during the course of imprisonment--on whether to grant parole or other forms of sentence reduction. In this article we study a model of the adjustment of sentences assuming that...

Theories of crime in economics focus on the roles of deterrence and incapacitation in reducing criminal activity. In addition to deterrence, a growing body of empirical evidence has shown that both income support and employment subsidies can play a role in crime reduction. This paper extends the...

Weak states enable private enforcement but it does not always fade away in the presence of strong states. We develop a general equilibrium model of the market organization of enforcers (self-enforcers, competitive specialized enforcers or monopoly) who defend endowments from predators. We...

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 this paper we consider possible links between the advent and diffusion of a number of new psychiatric pharmaceutical therapies and crime rates. We describe recent trends in crime and review the evidence showing mental illness as a clear risk factor both for criminal behavior and...