As preferred provider organizations (PPOs) become the dominant model of managedn health care in the private sector, policymakers have increasingly viewed PPOs as an attractive option for Medicare. In part to understand how PPOs might operate under the Medicare Program, CMS launched the Medicare PPO demonstration in January 2003. In this article, we examine how PPOs have operated so far under the demonstration, including PPO availability and market entry; premiums, benefits, and beneficiary cost sharing; and enrollment, market share, enrollee characteristics, and disenrollment to date.
