One of the biggest trade-offs between Medicare Advantage and traditional Medicare is that Medicare Advantage plans have a more limited network of doctors and other providers. The size and breadth of provider networks can be an important factor for beneficiaries when choosing between traditional Medicare and Medicare Advantage, and among Medicare Advantage plans. As of 2017, 19 million of the 58 million people on Medicare (33%) are enrolled in a Medicare Advantage plan, yet little is known about their provider networks.

19 million people on Medicare are in a #MedicareAdvantage plan, yet little is known about their provider networks. 

This report is the first known study to examine the size and composition of Medicare Advantage plans’ physician networks. This analysis draws upon data from 391 plans, offered by 55 insurers in 20 counties, and accounted for 14% of all Medicare Advantage enrollees nationwide in 2015. Key findings include:

• More than three in ten (35%) Medicare Advantage enrollees were in narrow-network plans while about two in ten (22%) were in broad-network plans. To some degree, the relative narrowness of plan networks masks the total number of physicians that enrollees could access, particularly in larger counties.
• Medicare Advantage networks included less than half (46%) of all physicians in a county, on average.
• Network size varied greatly among Medicare Advantage plans offered in a given county. For example, while enrollees in Erie County, NY had access to 60% of physicians in their county, on average, 16% of the plans in Erie had less than 10% of the physicians in the county while 36% of the plans had more than 80% of the physicians in the county.
• Access to psychiatrists was typically more restricted than for any other specialty. Medicare Advantage plans had 23% of the psychiatrists in a county, on average; 36% of plans included less than 10% of psychiatrists in their county. Some plans provided relatively little choice for other specialties as well; 20% of plans included less than 5 cardiothoracic surgeons, 18% of plans included less than 5 neurosurgeons, 16% of plans included less than 5 plastic surgeons, and 16% of plans included less than 5 radiation oncologists.
• Broad-network plans tended to have higher average premiums than narrow-network plans, and this was true for both HMOs ($54 versus $4 per month) and PPOs ($100 versus $28 per month).

Insurers may create narrow networks for a variety of reasons, such as to have greater control over the costs and quality of care provided to enrollees in the plan. The size and composition of Medicare Advantage provider networks is likely to be particularly important to enrollees when they have an unforeseen medical event or serious illness. However, accessing the information may not be easy for users, and comparing networks could be especially challenging. Beneficiaries could unwittingly face significant costs if they accidentally go out-of-network. Differences across plans, including provider networks, pose challenges for Medicare beneficiaries in choosing among plans and in seeking care, and raise questions for policymakers about the potential for wide variations in the healthcare experience of Medicare Advantage enrollees across the country.