In 2006, more than 6 million individuals were victimized by violent crimes. Although violence is below levels of the early 1990s, it remains high. The extent of violence and its impact highlight a critical need to develop and implement effective programs to reduce violence and victimization. Communities have initiated a wide range of such programs, and scholars have conducted numerous evaluations of varying quality of them. Reviews have found certain types of strategies and specific programs to be promising, but additional critical evaluations are needed to plan violence-reduction programs. This monograph assesses the implementation and impact of the One Vision One Life violence-prevention strategy in Pittsburgh, Pennsylvania. In 2003, Pittsburgh witnessed a 49-percent increase in homicides, prompting a "grassroots" creation and implementation of the One Vision One Life antiviolence strategy. This initiative used a problem-solving, data-driven model, including street-level intelligence, to intervene in escalating disputes, and seeks to place youth in appropriate social programs. Analysis of the program, which is modeled on similar efforts elsewhere, can help inform other efforts to address urban violence. Four appendices are included: (1) The Observational Strategy; (2) Designation of Target, Spillover, and Counterfactual Neighborhoods; (3) Technical Detail on the Outcome Analysis; and (4) Outcomes of Full Models Used to Test for Intervention and Spillover Effects. Individual sections contain footnotes. A bibliography is provided. (Contains 40 tables and 7 figures.) [This research is the product of a joint collaboration between the RAND Corporation and Michigan State University.]