Gun violence has reached epidemic proportions in the United States, where it is largely concentrated in urban areas. One recent successful response to gun violence was the Boston Gun Project, an interdisciplinary approach designed to reduce youth violence by reducing gang and gun violence. After the Boston Gun Project was launched in 1996, youth homicide decreased by almost two-thirds in the city. As a result of the success in Boston, NIH funded a RAND project that would seek to replicate the results of the Boston Gun Project elsewhere in the United States. The Los Angeles Police Department (LAPD) Hollenbeck area was chosen for the replication study; it is a 15-square-mile area east of downtown Los Angeles. Although the framework of the replication study would be the same as the Boston Gun Project, it was expected that the initiation in Los Angeles would differ based on the unique characteristics of gun and youth violence in Los Angeles. The Los Angeles project was targeted at gang violence and included increased LAPD patrols in the geographic area of a "triggering" event; more stringent enforcement of housing codes and of public housing eligibility rules; more stringent enforcement of parole and probation conditions; and referral of gun law violations to Federal prosecutors. The evaluation of the Los Angeles project focused on whether the intervention reduced violent crime, gang crime, and gun crime. The analysis compared crime rates for a 3 week period across three comparison areas. Overall, while gang crime and violent crime were reduced somewhat in the target area and in neighboring communities, the Los Angeles intervention was not implemented as designed and it did not develop dynamically in response to changing needs. The law enforcement aspect of the intervention was implemented before the social services aspect was in place and officers did not constantly reprioritize and reallocate resources after each violent incident in the target area. Finally, one of the main findings of the evaluation indicated that the agencies involved in the Los Angeles intervention did not take an ownership interest in the intervention. Future interventions, if they are to be successful, must gain the support of all agencies involved. Tables, figures, bibliography.