There is ample evidence that many clinical decisions made by physicians are inconsistent with current and generally accepted evidence. This leads to the underuse of some efficacious diagnostic, preventive or therapeutic services, and the overuse of others of marginal or no value to the patient. Evolving new payment and delivery models place greater emphasis on the provision of evidence-based services at the point of care. However, changing physician clinical behaviors is likely to be difficult and slow. Policy makers therefore need to design interventions that are most effective in promoting greater evidence-based care. To help identify modifiable factors that can influence clinical decisions at the point of care, we present a conceptual model and literature review of physician decision making. We describe the multitude of factors-drawn from different disciplines-that have been shown to influence physician point-of-care decisions. We present a conceptual framework for organizing these factors, dividing them into patient, physician, practice site, physician organization, network, market, and public policy influences. In doing so, we review some of the literature that speak to these factors. We then identify areas where additional research is especially needed, and discuss the challenges and opportunities for health services and policy researchers to gain a better understanding of these factors, particularly those that are potentially modifiable by policymakers and organizational leaders. 5 Many studies have observed large variations in clinical practice, across geographic areas and within local areas or even specific physician organizations. 6 We are undergoing rapid change in healthcare organization and delivery. Physicians are increasingly practicing in larger organizations and systems of care, in part prompted by widespread initiatives by federal, state, and private payers to improve care quality and lower costs. These reform efforts, such as patient-centered medical homes and accountable care organizations, along with significant federal funding of comparative effectiveness research, incentives for adoption of health information technology that includes decision support, and feedback on clinical quality performance raise the hope and expectation that clinical decision making will improve, with greater adherence to accepted evidence.Within this context, research and requisite data collection on key factors affecting physician decision making is necessary to design interventions and refine current ones. In this article, we present a conceptual framework for understanding factors contributing to physician clinical decision making, specifically those related to physicians' use of evidence at the point of care. With this framework, we conclude with directions for future research and the data needs necessary to conduct this research.We frame our discussion in the context of physician decision making as part of a broader inquiry into collecting data on physicians and their practice organizations. Of course, evidence...