Not only is it difficult for the average person to assess Medicare Advantage plan networks, but it’s also hard for researchers. Nevertheless, a few things have been teased out.
Working with plan directories — flawed though they may be — a Kaiser Family Foundation analysis examined the physician networks of almost 400 Medicare Advantage plans offered by 55 insurers in 20 counties in 2015. It found that networks of these plans included 46 percent of physicians in a county, on average.
In other words, if you selected a plan at random in these counties, you could expect that a bit less than half of doctors would be covered, at least according to its directory. (This does not necessarily mean those who are covered are taking patients or practicing in locations convenient for you.)
The study found considerable variation by specialty. Psychiatrists are least likely to be included in plan networks; a typical plan covered fewer than one-quarter of them. Ophthalmologist are most likely to be included; a typical plan covered nearly 60 percent of them. Depending on what kind of care you need, the extent to which plans cover specific specialists would be important to know. But there is no single source that meaningfully compares Medicare Advantage plans’ networks in the aggregate, much less by specialty.
This could change. A recent draft regulation would require Medicare Advantage, as well as other kinds of plans, to provide their directories in an electronic format that third parties could use to compare them, for example through apps or online.
Why do plans’ networks vary anyway? One possibility is that plans may strategically narrow or broaden their networks of certain specialties to try to attract more of the kind of enrollees they want (healthier, cheaper) and fewer of those they don’t (sicker, more expensive). Studies have shown that sicker beneficiaries are less attracted to Medicare Advantage, perhaps for these reasons. Another possibility, suggested by an Urban Institute study, is that plans narrow networks to control productivity and quality — for instance, covering only doctors who meet quality standards and tend to provide more efficient and valuable care.
A study of Medicare Advantage plans offered in California in 2017 found that the quality of obstetricians-gynecologists, cardiologists and endocrinologists covered by those plans tended to be comparable to those available through traditional Medicare. But some plan enrollees, particularly those in more rural areas, would need to travel far — in some cases exceeding 100 miles — to see those covered physicians.