Transparency exists along a continuum from documentation that a trial exists to full disclosure of the results data set at the end of the trial (Figure). “Trial registries” address one end of the spectrum by making public a summary of protocol details at trial initiation. “Results databases” provide public summaries of results for key trial endpoints, whether published or not. Some policies promote public access to data sets, such as the National Institutes of Health (NIH) Data Sharing Policy(16) and the Annals of Internal Medicine policy, which publishes author statements of willingness to share study protocols, statistical codes, and datasets.(17)