Under the Medicare+Choice program, firms have been able to offer products on a county by county basis, making participation decisions based on factors such as county payment rate, strength of local provider networks, and beneficiary's affinity for managed care. In 2003, Medicare+Choice payment rates paid to plans range from $495 in rural floor counties to a high of $872 in Staten Island, NY. Consequently, there is large national variation in benefits, premiums, and plan participation. A recent site visit to Palm Beach county and neighboring Miami-Dade highlighted many of the differences between counties which may pose challenges to firms trying to enter large service areas.
Nicholas, L. H., Dallek, G., & Biles, B. (2003). Medicare+Choice in Palm Beach: Watching and waiting?. Washington, D.C.: Center for Health Services Research and Policy, Department of Health Policy, School of Public Health and Health Services, The George Washington University.