We are currently witnessing a radical change in the health care system in the United States as a result of the managed care juggernaut. Driven by the imperative to stem increasing health care costs, managed care seeks to save money by “managing” health care utilization and narrowing the choices available to health care consumers. Although both cost-saving strategies are effective, they also present a potential threat to quality of care. As HEDIS and other measures of quality are revised, physicians must establish guidelines for quality of care that support the burgeoning managed health care environment. In developing these guidelines and measures, two important trends must be acknowledged and addressed. First, managed care was formerly confined mostly to middle class populations but now envelops many more diverse and vulnerable groups, including Medicaid, Medicare, and minority populations [1]. Second, providing care within a managed care environment requires attention to the population of “covered lives” in addition to individual patients.