I. Introduction
The U.S. healthcare system is in the process of shifting from traditional fee-for-service (FFS) payment to value-based alternative payment models (APMs).1 The number of APMs were significantly accelerated by the Patient Protection and Affordable Care Act (PPACA), which established the Medicare Shared Savings Program (MSSP) for accountable care organizations (ACOs).2 Ten years after the passage of PPACA, and five years after the passage of the Medicare Access and CHIP Reauthorization Act (MACRA),3 the evolution of these value-based reimbursement (VBR) models may provide some insight as to the future success of these arrangements. Toward that end, this article reviews recent trends and changes to federal, quasi-federal, and private APMs, and discusses the indications that may be drawn from these developments.