MA Switching Surges Among Dually Eligible Adults: Grace Mackleby, PhD

This week's Managed Care Cast episode features a conversation between The American Journal of Managed Care^® (AJMC^®) and Grace Mackleby, PhD, a research scientist at the USC Schaeffer Center, about her study, "Plan Switching Among Medicare Advantage Enrollees Dually Eligible for Medicaid," published in the September 2026 issue of AJMC.

The study examined how often beneficiaries switched from one Medicare Advantage (MA) plan to another or from MA to traditional Medicare (TM). It compared enrollees dually eligible for Medicaid with those eligible for Medicare only. Mackleby explained that dually eligible beneficiaries account for about one-fifth of the Medicare population and tend to have more chronic conditions, higher costs, and greater needs; they are also subject to different rules on when they can switch plans.

Mackleby and coauthors Angela Liu, PhD, and Erin Trish, PhD, used administrative Medicare enrollment data to track switching from 2016 to 2022. She highlighted 3 main results. First, about 22% of fully dually eligible enrollees switched MA plans in 2022, up from about 12% in 2016. Second, these enrollees were roughly 6 times more likely to switch to another MA plan than TM. Third, dually eligible beneficiaries overall switched MA plans more often than those eligible for Medicare only.

The study did not examine causes, but Mackleby pointed to 2 likely drivers: the growing number of available MA plans and the strong competition among insurers, which have heavily marketed supplemental benefits such as flex cards and dental coverage. For non–dually eligible beneficiaries, she added, it is difficult in most states to obtain Medigap coverage after enrolling in MA, which makes returning to TM financially unappealing.

Switching also varied by race and ethnicity. Black, Hispanic, and American Indian/Alaska Native fully dually eligible enrollees switched MA plans more often than non-Hispanic White enrollees. Mackleby said geography may play a role. However, higher switching could also indicate lower satisfaction with available plans, which warrants further study, she noted.

Looking ahead, Mackleby emphasized the need to understand whether switching helps or harms beneficiaries, including its effects on access to care and cost sharing. She also called for research on how switching shapes market performance.

"I think looking at it from a beneficiary welfare perspective is going to be really important, and then also looking at it from a market perspective is going to be important too," Mackleby concluded.

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