This study investigated the effect of a school-based violence prevention program on community rates of violence for youth aged 10 to 18 in three urban communities with high rates of crime and poverty. We evaluated the impact of the Olweus Bully Prevention Program (OBPP) combined with a family intervention using a multiple baseline design in which we randomized the order and timing of intervention activities across three schools. Outcomes were police reports of violent crime incidents involving offenders aged 10 to 18 years (N = 2859 incidents) across a 6-year period. We used Bayesian hierarchical regression modeling to estimate the reduction of youth violence in the census blocks of the intervention middle school zones. Models controlled for percent female head-of-household, median household income, and percent renter-occupied housing units. Block groups within the attendance zones of schools receiving the intervention had a reduced risk of violence compared with those that did not (relative risk = 0.83, 95% credible interval = 0.71, 0.99). Our findings suggest that the school-level intervention was associated with a significant reduction in community-level youth violence. Public health professionals, program planners, and policy-makers should be aware of the potential community-wide benefit of school-level interventions.
Keywords: Community effects; Spatial analysis; Violence prevention; Youth violence.