A January 2015 Kaiser Family Foundation study shows that the overwhelming majority of people newly eligible for Medicare enroll in traditional Medicare. About 70 percent of people with Medicare are enrolled in traditional Medicare.
Traditional Medicare offers coverage from more than 90 percent of doctors and virtually every hospital in the United States. Not surprisingly, fewer than five percent of these people switched into a Medicare Advantage plan in any year between 2006 and 2011. Medicare Advantage plans restrict access to doctors and hospitals.
Traditional Medicare has greater upfront costs than most Medicare Advantage plans because you need supplemental coverage in order to be protected from financial risk. That supplemental coverage can be expensive if it is not through Medicaid or a generous employer retiree plan. But, for anyone with substantial health care needs, deductibles and copays in a Medicare Advantage plan can end up costing a lot more.