What Does the Downshifting of Some of Medicare’s Pioneer ACOs Really Mean?

The July 16 announcement by the Centers for Medicare & Medicaid Services that nine of the 32 patient care organizations participating in the Pioneer ACO Shared Savings Program were leaving the Pioneer program, with two of them leaving the Medicare Shared Savings Program altogether, was cause for reflective pause. But is the glass half-empty or half-full in this case?