M. Susan Ridgely

Photo of M. Ridgely
Adjunct Senior Health Policy Researcher; Codirector, RAND Center of Excellence on Health System Performance; Affiliate Faculty, Professor of Policy Analysis, Pardee RAND Graduate School
Off Site Office


J.D. in health law, University of Maryland School of Law


M. Susan Ridgely is an adjunct senior health policy researcher at the RAND Corporation and a Pardee RAND Graduate School affiliate faculty member. She has more than 30 years of experience in health services research and policy analysis.

She has led numerous grant and contract projects for government, foundation, and private funders. Her recent research activities include projects on innovation in health care organization and financing, patient safety, and medical liability. She is co-director of the RAND Center of Excellence on Health System Performance, a five-year, multi-institutional center funded by AHRQ to characterize high-performing health systems and identify the most effective ways to promote the uptake of evidence-based practice in health care delivery systems.

In past projects Ridgely conducted studies of the cost and quality performance of California physician organizations, the IHA Bundled Episode Payment and Gainsharing Demonstration, and the Blue Shield of California's Accountable Care Organization (ACO) Infrastructure Grant Program. She was also the RAND principal investigator for the longitudinal evaluation of the HHS Patient Safety and Medical Liability Initiative.

Ridgely employs site visit, interview, focus group, and survey methodologies to understand innovations in health care, to derive "lessons learned," and communicate those lessons to policymakers and other stakeholders. She has coauthored over 75 peer-reviewed articles, law review articles, monographs, and reports in the health and behavioral health fields. Ridgely received her J.D. from the University of Maryland School of Law. 

Recent Projects

  • RAND Center of Excellence on Health System Performance
  • Evaluation of IHA Value-Based P4P on Reducing Total Cost of Care
  • Longitudinal Evaluation of HHS Patient Safety and Medical Liability Initiative
  • IHA Bundled Episode Payment and Gainsharing Demonstration
  • Blue Shield of California's ACO Infrastructure Grant Program

Selected Publications

Ridgely, M.S., Timbie, J.S., Wolf, L.J., Duffy, E.L., Buttorff, C., Tom, A., Vaiana, M.E., Consolidation by Any Other Name: The Emergence of Clinically Integrated Networks. , RAND Corporation (RR-A370-1), 2020

Ridgely, M.S., Duffy, E., Wolf, L., Vaiana, M., Scanlon, D., Buttorff, C., Leitzell, B., Ahluwalia, S., Hilton, L., Agniel, D., Haviland, A., and Damberg, C, "Understanding U.S. health systems: Using mixed methods to unpack organizational complexity," eGEMs (Generating Evidence & Methods to Improve Patient Outcomes), 7(1), 2019

Ridgely, M.S., Buttorff, C., Wolf, L.J., Duffy, E.L., Tom, A., Damberg, C., Scanlon, D.P., Vaiana, M.E., "The importance of understanding and measuring health system structural, functional, and clinical integration," Health Services Research, 55, 2021

Ridgely, M.S., Ahluwalia, S., Tom, A., Vaiana, M., Motala, A., Silverman, M., Kim, A., Damberg, C., and Shekelle, P. , "What are the determinants of health system performance: Findings from the literature and a technical expert panel ," Joint Commission Journal on Quality and Patient Safety, 46, 2019

Damberg, C., Silverman, M., Burgette, L., Vaiana, M. and Ridgely, M.S. , "Are value-based incentives driving behavior change to improve value? ," American Journal of Managed Care, 25(2), 2019

Waxman, D.A., Greenberg, M.D., Ridgely M.S., Kellerman, A., Heaton, P., "The effect of malpractice reform on emergency department care," New England Journal of Medicine, 371(16), 2014

Ridgely, M.S., De Vries, D., Bozic, K.J., Hussey, P.S., "Bundled payment fails to gain a foothold in California: The experience of the IHA Bundled Episode Payment and Gainsharing Demonstration," Health Affairs, 33(8), 2014

Ridgely, M.S., Greenberg, M., Pillen, M. & Bell, J., "Progress at the intersection of patient safety and medical liability: Insights from the Patient Safety and Medical Liability Demonstration Program," Health Services Research, 51(supplement), 2016

Honors & Awards

  • President's Award, RAND Corporation


  • Unrecognizable clinician presenting a deal between a small hospital and a larger health care provider organization, photo by LeoWolfert/Getty Images

    Does Vertical Integration Improve or Imperil U.S. Health Care?

    Health care consolidation is endemic across the United States. With consolidation has come public attention and regulatory scrutiny. Unfortunately, evidence is accumulating that health care consolidation is harming competition in the U.S. health care market, while neither reducing costs nor improving care.

    Nov 16, 2021 HealthCare Business News

  • U.S. currency wrapped around prescription bottle

    The Winding Path to Effective Bundled Payment

    It's not unusual for a demonstration to fall short of its original objectives. Learning from such cases is part of the innovation process. This is especially worthwhile for bundled payment, which has many potential benefits for patients, providers, and payers.

    Aug 29, 2014 Health Affairs Blog

  • hospital staff meeting

    ACOs: Making Organizations 'Accountable' for Care

    The Affordable Care Act focuses primarily on extending coverage to uninsured Americans, but it is also intended to help curb cost growth. M. Susan Ridgely explains one of the key tools for doing that—the “accountable care organization,” an alternative delivery model intended to lower costs while also improving quality of care.

    Dec 19, 2012

  • An elderly woman sorting multiple prescriptions

    Could Liability Concerns Derail Clinical Decision Support?

    Computerized clinical decision support (CDS) systems have been developed to enhance physician decisionmaking and reduce the incidence of avoidable medical errors. Drug-drug interaction warnings are a mainstay of CDS systems, but they give rise to a fundamental problem that limits the utility of the systems to date.

    Jul 6, 2012

  • Clinical Decision Support and Malpractice Risk

    From the standpoint of policy makers, the basic challenge is to ensure that liability concerns do not derail the clinical value of new CDS technology, write Michael Greenberg and M. Susan Ridgely.

    Jul 6, 2011 The Journal of the American Medical Association