2019 HSR Impact Award: Impact, Mechanisms, and Design of the Medicare ACO Programs

2019 HSR Impact Award: Impact, Mechanisms, and Design of the Medicare ACO Programs

This publication outlines a body of work spanning 30 papers over 7 years that examines Medicare ACOs by J. Michael McWilliams and key team members Michael Chernew, Bruce Landon, and Laura Hatfield.

Download Publication

The evaluation work by J. Michael McWilliams and colleagues has contributed substantially to the scientific basis for continued development of population-based payment models. Insights gained about the mechanisms of ACO impact have changed the conversation. These insights, cited in regulations and official reports, coupled with the team’s engagement in the policy process have directly informed ACO program reforms and design in numerous concrete ways. These include, for example, weakening the link between savings and subsequent “rebasing” of ACO benchmarks, slowing the transition to regional benchmarks for ACOs with above-regional spending, accommodating smaller ACOs, modifying patient attribution rules, and refining the treatment of overlap between ACO and bundled payment models.

The work also has broader implications for the structure of the delivery system. For example, McWilliams and colleagues demonstrated that, contrary to expectations, provider consolidation has not accelerated as the result of providers entering ACO contracts. This finding, coupled with the finding that smaller physician-group ACOs have generated more savings, questions the widespread use of ACO formation as a justification for mergers, acquisitions, or regulatory relief from antitrust law.

The AcademyHealth Board of Directors created the HSR Impact Award to recognize research that has had a significant impact on health and health care. The award, which is supported by AcademyHealth, is intended to identify and promote examples of outstanding research that have been successfully translated into health policy, management, or clinical practice.

Dr. McWilliams Headshot

J. Michael McWilliams, M.D., Ph.D.

Warren Alpert Foundation Professor - Harvard Medical School

Dr. McWilliams is the Warren Alpert Foundation Professor of Health Care Policy and a Professor of Medicine at ... Read Bio