RWJF Health Data for Action – The HD4A program will fund innovative research that uses the available data to answer important research questions. Applicants under this Call for Proposals (CFP) will write a proposal for a research study using data from either the Health Care Cost Institute (HCCI) or athenahealth. Successful applicants will be provided with access to these data, which are described in greater detail below. The HCCI and athenahealth data provide a wealth of private claims data and rich detail on care delivery and patient obesity-related measures, respectively. The proposed studies should enable relevant, innovative, and actionable research that uses the available data to answer important, policy-relevant questions.