Between 1994 and 2001, the Office of Community Oriented Policing Services (COPS) provided more than $7.6 billion in grants to state and local communities to hire police officers and promote community policing as an effective strategy to prevent crime. Studies of the impact of the grants on crime have been inconclusive. GAO was asked to evaluate the effect of the COPS program on the decline in crime during the 1990s. GAO developed and analyzed a database containing annual observations on crime, police officers, COPS funds, and other factors related to crime, covering years prior to and during the COPS program, or from 1990 through 2001. GAO analyzed survey data on policing practices that agencies reportedly implemented and reviewed studies of policing practices. GAO assessed: (1) how COPS obligations were distributed and how much was spent; (2) the extent to which COPS expenditures contributed to increases in the number of police officers and declines in crime nationwide; and (3) the extent to which COPS grants during the 1990s were associated with policing practices that crime literature indicates could be effective. In commenting on a draft of this report, the COPS Office said that our findings are important and support conclusions reached by others.