Li J, et al. - Federal policymakers have recommended greater transparency regarding the quality of care delivered by the healthcare sector, in large part to empower patients and caregivers. Physician Compare—the Centers for Medicare & Medicaid Services’ flagship website about the quality of care provided by US physicians and other clinicians—is in its final phase of expansion to further help patients and their caregivers select high-quality clinicians. However, it is unclear whether Physician Compare is comprehensive, given that reporting is voluntary, clinicians choose the measures, and the Centers for Medicare & Medicaid Services displays a subset of measures. Thus, using current data from Physician Compare, researchers determined the following: how many and which types of clinicians have quality information, how comprehensive the quality data are, and how well the measures differentiate the performance of included clinicians.