Standardized public reporting on the quality of health care (report cards)offers an opportunity to empower purchasers and consumers so that they can make choices that can result in better health care for less money. However,not all population subgroups are equally well served by the publication of such data. In particular, vulnerable patient groups such as the poor, the less educated, the chronically sick, and members of ethnic or linguistic minorities may find issues of importance to them largely neglected. In addition, the way that report card data are collected, analyzed, and presented may further marginalize the experiences of these groups who in any case are already underserved by the health system. This observation also has important implications for health care providers who serve primarily large numbers of vulnerable patients. The differential impacts of report card data on vulnerable patient groups (and their providers) need to be addressed by researchers and policy makers if access issues are not to be damaged further by the providers' pursuit of quality and value.