Study: ACO Leaders Share Priorities, Challenges in Medicare Shared Savings Program


Leaders at 49 accountable care organizations (ACOs) shared their perspectives on the Medicare Shared Savings Program, as well as a range of strategies for success and ongoing challenges.

Leaders of accountable care organizations (ACOs) reported shifting strategies and a range of challenges with the Medicare Shared Savings Program (MSSP) in a qualitative study published in JAMA Health Forum.1 The findings could prove useful to policy leaders as they reform the program, according to the study authors.

“The MSSP ACO model is one of the largest and longest-running value-based payment efforts in the United States. We wanted to understand how high-level policy influences on-the-ground care,” study author Dhruv Khullar, MD, MPP, physician and assistant professor of health policy and economics at Weill Cornell Medical College, told The American Journal of Managed Care® in an email. “In particular, we wanted to learn how ACO leaders are trying to improve care for patients and what challenges they face in doing so, especially given recent changes to the ACO program and broader trends in US health care.”

The MSSP includes more than 400 ACOs and has been running continuously for more than a decade. Approximately 11 million patients were attributed to ACOs in 2022, which is about 1 in 6 Medicare beneficiaries, about 1 of 3 being in the fee-for-service program.2

Cash money stethoscope cost | Image credit: adragan -

Cash money stethoscope cost | Image credit: adragan -

The authors explained that different ACO models and tracks allow organizations to take on various levels of financial risk when taking part in value-based initiatives. Savings or losses in the MSSP are calculated by comparing organizations’ annual costs to their own historical spending and to regional spending benchmarks since 2017.1

“Research suggests that MSSP has led to modest improvements in quality and spending for Medicare beneficiaries, but observers have also raised concerns about adverse patient selection, inadequate risk adjustment, and perverse benchmarking incentives,” the authors wrote. Survey-based qualitative research has been conducted previously, but the perspectives of ACO leaders have not been characterized since changes to MSSP and the US health care system in recent years.

The study authors conducted in-depth semistructured interviews with leaders at 49 ACOs to characterize the initiatives they prioritize to try to succeed in the MSSP, how they approach clinician engagement with ACO goals and performance improvement, and strategies for recruiting practices and clinicians.

“ACO leaders identified a number of key strategic priorities and these varied somewhat across ACOs,” Khullar said. “However, many leaders reported a focus on annual wellness visits, ensuring their attributed patients’ medical conditions were captured through coding efforts, and an emphasis on improving transitions across care settings.”

Thirty-four (69%) of the participating ACOs were associated with hospitals, 35 were considered medium or large (71%), and 17 were rural (35%). The mean (SD) tenure of the participating ACOs in MSSP was 8.1 (2.1) years. The characteristics of participating and nonparticipating ACOs were similar.

A total of 5 main themes were identified in the interviews:

  • Key programmatic initiatives
  • Clinician engagement
  • Shared savings distribution
  • Recruitment and retention
  • Hospital-associated ACOs

Regarding programmatic initiatives, ACO leaders reported focusing their efforts on increasing annual wellness visits, ensuring rigorous coding to capture patients’ complexity, and improving transitions of care. Managing post-acute care was of particular interest, and many leaders reported working closely with physicians to ensure referrals to high-quality subacute rehabilitation facilities.

Relationship-based and metrics-based strategies were implemented to encourage physician alignment with the goals of ACOs, and many implemented dashboards so clinicians could view their performance on quality and cost measures. Engagement with such dashboards varies by clinician, however. Meeting with physicians and discussing the rationale for new initiatives was another way some ACOs emphasized personal relationships to engage clinicians.

Shared savings distribution approaches varied between ACOs when minimum savings thresholds were met. Most of the ACOs distributed at least half of shared savings to practices, and often more than half in markets with high competition for recruitment. Payments at the practice level were most often distributed based on attributed patients, while some aimed to disperse payments based on performance.

Market competition due to health system consolidation and large medical groups increasingly influenced recruitment and retention strategies, as did the growth of Medicare Advantage. Interest and participation in MSSP were difficult to maintain, some leaders reported, noting that the number of patients and clinicians engaging in other forms of care is growing. Presenting a comparison between ACO participation and The Merit-based Incentive Payment System, which increases administrative burden, was one helpful tactic several leaders mentioned.

The final theme was whether hospitals help or hurt ACO objectives, and leaders of ACOs associated with hospitals held mixed views. Getting alignment on reduced utilization can be particularly challenging with hospitals, some said. Others framed the inclusion of hospitals as advantageous, noting that they often have more resources vs medical groups and that their integration can smooth care transitions.

While the study included a large number of ACOs and conducted interviews, which garnered nuanced responses compared with some survey formats, it was also limited because the authors could not determine whether the reported strategies were associated with objective care improvements. Interviewees could also have selected the most favorable parts of their work, and questions focused on failures could have elicited different responses.

“We need more research to understand how ACOs engage frontline clinicians,” Khullar said. “Most current work focuses on how ACOs are incentivized, but examining how those incentives are felt by clinicians providing care is crucial.”


1. Khullar D, Schpero WL, Casalino LP, et al. Accountable care organization leader perspectives on the Medicare Shared Savings Program: a qualitative study. JAMA Health Forum. Published online March 15, 2024. doi:10.1001/jamahealthforum.2024.0126

2. National Association of ACOs (NAACOS). Homepage. Accessed May 3, 2024.

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