PROJECT ABSTRACT Two approaches promoted in the current RFP and the CDC’s STOP SV Strategies guidance are 1) Promoting Social Norms that Protect Against Violence, and 2) Creating Protective Environments. The current proposal to evaluate Close to Home (C2H), a community mobilization SV prevention model, incorporates both approaches within a rigorous and innovative research design. Community mobilization to prevent SV, including the C2H model, is designed to create deep social norms change and enhance protective community environments, yet has rarely been evaluated. We propose to rigorously evaluate the C2H model via a cluster-matched control trial across 14 diverse communities in California via collection and analyses of social network, social media and community-wide school-based data in order to provide much-needed evidence on the effectiveness of this community-level approach to prevent SV. California is uniquely poised to conduct this research given a) the number of communities implementing C2H, b) CDPH’s 10-year commitment to building capacity to support local implementation of this model, and c) CDPH’s ongoing partnership on RPE evaluation with University of California San Diego’s Center on Gender Equity and Health, a center with the highest levels of expertise in evaluation of sexual violence prevention programs, social network science, and assessing norms across social networks and social media. We propose a highly-innovative, multi-level evaluation of C2H involving the following aims: 1) Develop and implement a cluster-matched control design in partnership with the Research Advisory Board, including collecting baseline social network and social media data across 14 diverse California communities; 2) Evaluate effects of the C2H model on social norms and community connectivity regarding SV, and SV incidence via longitudinal analyses of baseline and 24-month follow-up social network data; and 3) Extend Aim 2 findings via analyses of community-level effects on SV social norms and behavior based on multiple waves of community-level school-based data and geocoded social media data. The proposed research will fill a critical evidence gap in SV prevention by evaluating effects of C2H, a promising community mobilization SV prevention model, on community-level social norms, community connectivity (a key element of protective environments), and SV incidence in accordance with CDC’s STOP SV guidance. Proposed longitudinal social network analyses will also provide the first evidence regarding diffusion of changes in SV social norms and behaviors. These contributions will accelerate prevention of sexual violence by equipping local, state and national stakeholders with the rigorous and generalizable evidence needed to inform implementation of community-level sexual violence prevention programming.