Abstract: Among the core missions of the U.S. Food and Drug Administration (FDA) are protecting public health by assuring the safety and efficacy of drugs, biologics, and medical devices and advancing public health by promoting scientific research and medical innovation (1). According to its mandate, the decisions made by the FDA in fulfilling these missions should be guided by scientific considerations, not economic or political ones. However, several recent, high-profile episodes have highlighted the fact that the FDA is buffeted by many external influences (2, 3). Such controversies require us to distinguish between legitimate influences that would improve the FDA or enhance its regulatory mission, illegitimate influences that seek to corrupt or undermine the agency, and influences that may be legitimate but nevertheless harm public health or patient outcomes. We present a decision framework to assist regulators, policy-makers, judges, physicians, and the public in evaluating the legitimacy and value of external influences on the FDA.