PROJECT SUMMARY Despite the recognition of health disparities in obesity, behavioral interventions among low-income and minority populations have consistently met with limited success. This is partially explained by social determinants of health. Barriers at the community level impede consistent engagement in healthy behaviors. The proposed ancillary study adds objective community-level data and corresponding analyses to an ongoing behavioral obesity intervention for low-income Latino families, entitled COACH (R01HD100458 from NICHD, PI Heerman). By using a comprehensive measurement approach that considers the physical activity environment, the food environment, the social environment, and the historical/structural environment, we aim to characterize these complex and cumulative contextual risks for children enrolling in our ongoing COACH clinical trial. COACH (COmpetency-Based Approaches to Community Health) implements a personally tailored approach, equipping families to engage in health behaviors despite dynamic barriers. COACH is a multi-level intervention targeting 1) the individual child through developmentally appropriate health behavior curriculum, 2) the family by addressing parent weight loss directly and engaging parents as agents of change for their children, and 3) the community by building capacity of Parks and Rec centers to offer parent-child programming. Using novel multi-component assessments throughout the two years of the study, the intervention identifies individual, family, and community barriers to healthy behaviors and delivers structured yet personalized intervention content in 7 domains: fruits/vegetables, snacks, sugary drinks, physical activity, sleep, media use, and parenting. This ancillary proposal seeks to augment the data collection by adding key community-level contextual variables to measure the moderating impact of those variables on the effectiveness of the intervention. We propose collecting data related to urban density; food access, availability, and quality; multiple components of the physical activity environment; and variables related to social inequality. We will combine data from 1) prospectively conducting neighborhood and grocery store surveys and 2) local and national publicly available datasets to identify individual-level assessments of community-risk that can then be incorporated into the analysis plan for the main trial. In addition to conducting individual moderator analyses for each of the variables, we will conduct a prospective cohort analysis to evaluate their cumulative impact on child BMI over time.