Around half of people with Medicare get their health coverage from Original Medicare and the other half from Medicare Advantage, also known as a Medicare private health plan or Part C. Individual needs, preferences, and priorities typically guide these enrollment choices. This fact sheet outlines key considerations beneficiaries often keep in mind when deciding between the two coverage pathways.

Created in 1965, Medicare initially included Inpatient/Hospital insurance (Part A) and Outpatient/Medical insurance (Part B) and paid providers directly on a fee-for-service basis. The program has seen many legislative reforms over the years, including the addition of Medicare Advantage (Part C) in 1996. Although this change formally allowed enrollees to receive their Medicare benefits from a private insurance plan that contracts with the federal government, health plans have long played an important role in Medicare. In this fact sheet, we trace that evolution.

Many people can struggle to choose a Medicare Advantage plan that best meets their needs. For both newly eligible enrollees and those re-evaluating their options, the plan comparison process can be complex and burdensome, undermining active, informed coverage choices. Once enrolled, these decisions and Medicare Advantage-specific features—such as restrictions on providers and barriers to services—may limit enrollee access to care in unanticipated and harmful ways. Learn more about the beneficiary experience with Medicare Advantage in this fact sheet.

Under Original Medicare, Medicare pays providers a fixed rate for each service rendered to enrollees. By contrast, Medicare pays private Medicare Advantage plans a fixed monthly rate for each enrollee; the plans then pay providers to deliver care. The Medicare Advantage payment rates are set annually through a complicated series of determinations and adjustments that have significant bearing on Medicare financing. In this fact sheet, we review those processes and impacts.

Flaws in the Medicare Advantage payment formula yield inflated plan payments that grow with enrollment. Plans use these additional dollars to offer services Original Medicare does not cover. They heavily and successfully market these “supplemental benefits,” boosting enrollment and triggering even more overpayments. Plans invest those funds to attract more enrollees, and the cycle begins again. This fact sheet explains this harmful pattern and what it means for Medicare solvency.

Like other Medicare enrollees, people who are dually eligible for Medicare and Medicaid can choose to receive their Part A and Part B benefits through Original Medicare (OM) or from a private Medicare Advantage (MA) plan. Some who select MA may have access to a Dual Eligible Special Needs Plan (D-SNP) which is an MA plan exclusive to people enrolled in both programs. In this fact sheet we examine D-SNPs’ potential to improve integrated care and the beneficiary experience.