Given the early success of these three modest interventions and given the consistency of the basic finding, it would seem worthwhile to learn more about the longer term impacts. Thus, the committee recommends that a sustained and systemic research program be devoted to studying the impact of different place-based gun suppression patrol and targeted policing approaches in general. These evaluations should focus on replicating the existing evidence in different settings, running experimental evaluations, and formalizing and estimating behavioral models of policing and crime. Additional evaluations should assess the longer term impacts, paying particular attention to issues of substitution, adaptation, and deterrence.

A small number of chronic offenders generate a disproportionate share of crime. In their seminal study of nearly 10,000 boys in Philadelphia, Wolfgang et al. (1972) revealed that the most active 6 percent of delinquent boys were responsible for more than 50 percent of all delinquent acts committed. The RAND Corporation’s survey of jail and prison inmates in California, Michigan, and Texas revealed that, in all three states, the most frequent 10 percent of active offenders committed some 50 percent of all crimes and 80 percent of crimes were committed by only 20 percent of the criminals (Chaiken and Chaiken, 1982). Moreover, 1 percent of offenders committed crimes at the very high rate of more than 50 serious offenses per year (Rolph et al., 1981).

The observation that a small number of highly active offenders generates a large share of the crime problem is an important insight for law enforcement agencies with limited resources to prevent crime. Many serious urban crime problems, for example gang violence, are driven by groups of these criminally active individuals. Focusing criminal justice attention on a small number of high-risk offenders may be a promising way to control gun violence.

The Firearm Suppression Program (FSP) sought parental consent to search for and seize the guns of juveniles (Rosenfeld and Decker, 1996). While this program was not explicitly focused on dangerous offenders, it represents a police program to prevent firearm-related violence by disarming a very risky population of potential gun offenders—juveniles. The program was operated by the St. Louis Metropolitan Police Department’s Mobile Reserve Unit, which is a police squad dedicated to responding to pockets of crime and violence throughout St. Louis (Rosenfeld and Decker, 1996). Home searches were initiated on the basis of resident requests for