Abstract
The Medicare Health Outcomes Survey (HOS) provides a rich source of outcomes data on the Medicare Advantage (MA) program for the US Department of Health and Human Services, managed care organizations participating in Medicare, quality improvement organizations, and health services researchers working to improve quality of care for Medicare enrollees. Since 1998, the Centers for Medicare and Medicaid Services has collected longitudinal functional status information to assess the performance of Medicare managed care organizations. This introduction reviews the goals of the HOS program, how the HOS supports health care reform, and outlines recent HOS studies exploring data applications for monitoring outcomes and implementing quality improvement activities.