How Some Major Accountable Care Organizations Work

Medicare Shared Savings Program

Number of participants: 220, with more set to join Jan. 1, 2014.

Run by: Centers for Medicare and Medicaid Services (CMS).

How it works: Participants include many smaller and less experienced organizations that may need more time and resources to integrate their health care delivery. ACOs can choose between a one-sided, shared savings model with no downside risk and a two-sided model that offers more reward in exchange for assuming some financial risk.

To learn more: cms.gov/sharedsavingsprogram.

Pioneer ACO Program

Number of participants: 32

Run by: The Center for Medicare and Medicaid Innovation at CMS.

How it works: Participants are experienced in coordinating patient care, and many are already operating under ACO-like arrangements. The first two years feature several shared savings and risk models, with an option in the third year for successful groups to transition to a population-based payment model.

To learn more: innovation.cms.gov/initiatives/Pioneer-ACO-Model.

Physician Group Practice Transition Demonstration

Number of participants: 3 (of the original 10 participants, 7 have joined the Pioneer or Shared Savings models).

Run by: CMS

How it works: Now winding down, this demonstration effectively extended Medicare’s first pay-for-performance initiative for physicians, the Physician Group Practice Demonstration that ran from 2005 to 2010. Like the initial program, the transition demonstration features a shared savings payment model under which participants can earn incentive payments if they meet quality performance benchmarks.

To learn more: Visit cms.gov/Medicare and click on “Demonstration Projects.

Medicaid-Only ACOs

How many participants: 10, with more in development.

Run by: Individual states, including Massachusetts, Colorado, Minnesota, New Jersey and Oregon (Oregon runs two separate ACOs).

How they work: States are applying their own experimental approaches, but most involve risk-based managed care as the main delivery and payment system, with coordinated communication and shared budgets. More states are expected to form these organizations to more efficiently handle their Medicaid populations; others have set up private contracts or are operating ACOs through private managed care plans.

To learn more: The Kaiser Family Foundation has a good overview of Medicaid ACOs at kff.org/medicaid/upload/8319.pdf.

Private ACOs

How many participants: 184 private entities, not including 49 hybrid Medicare-private ACOs operating under the Pioneer or Shared Savings models.

Run by: A variety of entities. Although most ACOs were initially sponsored by hospital systems, those backed by physician groups are quickly gaining ground. Insurers and community-based organizations are also getting their own ACOs off the ground.