As Medicare Advantage attracts a greater share of Medicare-eligible enrollees, switching from fee-for-service Medicare to MA has been on the rise since 2010 and peaked at 7.8% in 2021, according to new research published in Health Affairs. Researchers used data from the CMS Medicare Enrollment Database and the Risk Adjustment Processing System, and their primary objective was to understand where the bulk of new MA membership is coming from (i.e., FFS Medicare vs. new-to-Medicare) and those individuals’ health profiles. After 2010, switching from MA to FFS Medicare consistently declined while switching in the other direction increased, with the greatest difference in rates occurring in 2021, when just 1.2% of individuals left MA for FFS Medicare, according to the analysis. (The switching rate was defined as the percentage of switchers out of the total number of switchers and stayers in either FFS Medicare or MA.) Between December 2021 and December 2022, the overall switching rate from FFS to MA averaged 7.4%, and men had a higher switching rate than women, researchers observed. During that time, the switch rate from FFS to MA was highest for Black beneficiaries (15.6%), closely followed by Hispanic beneficiaries (15.0%), and the lowest rate was among white enrollees (6.4%). Researchers noted their analysis was descriptive in nature and that they were not able to discern the underlying factors driving the observed switching patterns, such as aggressive marketing or attractive plan benefits. Moreover, the analysis did not differentiate between voluntary and involuntary switching. As the MA program continues to grow, however, “understanding reasons for switching will become important,” they observed.