This bulletin draws on findings from an independent evaluation, conducted by the Urban Institute, of the Gang Reduction Program's (GRP) Impact in Los Angeles, California; Milwaukee, Wisconsin; North Miami Beach, Florida; and Richmond, Virginia, to examine how effectively these sites implemented the program. Following are some of the authors' key findings: (1) In contrast to many previous crime prevention and reduction efforts, all sites successfully implemented the GRP model. Three of the four sites also implemented plans to sustain elements of the program as federal funding expired; (2) Successful outcomes related to crime reduction were seen in most of the sites although results varied; (3) Strong leadership of a site coordinator, close oversight by the Office of Juvenile Justice and Delinquency Prevention (OJJDP) during the strategic planning and implementation phases, and the availability of technical assistance contributed to implementation progress of the sites; and (4) GRP is not a one-size-fits-all approach to gang prevention and reduction. The model is flexible enough that sites can adapt it to local conditions yet remain true to the original design. (Contains 5 figures and 11 endnotes.)