Coalition-based efforts that use a science-based approach to prevention can improve the wellbeing of community youth. This study measured several coalition capacities that are hypothesized to facilitate the adoption of a science-based approach to prevention in communities. Using data from 12 coalitions participating in a community-randomized trial of the prevention strategy Communities That Care (CTC), this paper describes select measurement properties of five salient coalition capacities (member substantive knowledge of prevention, member acquisition of new skills, member attitudes toward CTC, organizational linkages, and influence on organizations), as reported by coalition members, and examines the degree to which these capacities facilitated the community leader reports of the community-wide adoption of a science-based approach to prevention. Findings indicated that the five coalition capacities could be reliably measured using coalition member reports. Meta-regression analyses found that CTC had a greater impact on the adoption of a science-based prevention approach in 12 matched pairs of control and CTC communities where the CTC coalition had greater member (new skill acquisition) and organizational capacities (organizational linkages).