Which Medicare markets deserve attention?

MA & other health plan share is the share of a county's Medicare beneficiaries enrolled in Medicare Advantage or another Medicare health plan (cost plans, PACE and demonstrations included), rather than Original Medicare. A county at 70% means seven in ten local Medicare beneficiaries are enrolled in Medicare Advantage or another Medicare health plan rather than Original Medicare.

Basis: MA & other health plans ÷ all Medicare beneficiaries (Parts A and/or B). The CMS numerator MA_AND_OTH_BENES counts Medicare Advantage plus cost plans, PACE and demonstrations, so this is not an MA-only share.

Share change is that share today minus the same month a year ago, in percentage points. Unlike enrollment growth, it is not raised by growth in the Medicare population itself.

Two counties with the same share can have moved differently: a 70% county that gained 0.2 points and a 40% county that gained 3 points are different situations. Neither figure shows why the share moved, or where future enrollment will come from; the charts below plot both so the question can be investigated.

Each ball is one county. Further right means a higher MA & other health plan share; higher up means the share rose more over 12 months; further back means more MA & other health plan enrollees.

The left, high and far back corner holds large counties where the share is lower but rose over the year. That pattern records recent share gains in a large county; it does not show that more beneficiaries will switch, or that the county is an opportunity for a particular plan. The right and flat corner is the opposite. Investigate In a large county with a high share and little change, how much movement is between plans rather than out of Original Medicare? These counts cannot say; plan-level enrollment (CMS CPSC) and your own disenrollment data can.