Used in close to 30 countries, impacting close to 200 million lives

The ACG® System has been used in commercial and research settings worldwide, longer and more extensively than any other system on the market today. The software component is tried and true, continuously undergoing improvements and modifications in response to user needs.

Backed by Johns Hopkins University

The ACG System continues to evolve through research and development conducted at the Johns Hopkins Bloomberg School of Public Health, a world renowned institution. Over the past 30 years, the ACG System has been maintained and supported by dedicated Johns Hopkins faculty and staff in medicine, biostatistics, and health economics. Johns Hopkins University also offers support services by academic professionals to ensure appropriate implementation of the ACG System as well as accurate interpretation of the results.

Ongoing Research and Testing

The ACG System benefits from extensive global validation and testing. The ACG System Bibliography contains close to 1,000 published articles and reports from around the globe demonstrating its robustness in varying health care system contexts.

Improving Patient Outcomes

The ACG System facilitates the identification of multi-morbid patients with complex needs to enable timely care interventions. Available to all ACG System users, Guided Care® is a program designed to help primary care practices meet the complex needs of patients with multiple chronic conditions, where case mix is combined to support patient management.

The ACG System Team

Characterized by excellence in both research and practice, The ACG System Team has been creating risk measurement and case mix categorization methodology for more than 30 years, continuously refining and updating the system. Our team has virtually “written the book” on risk adjustment through numerous contributions in the published literature.

The Johns Hopkins ACG System White Paper– Describing the key applications and unique benefits.



barbaraJohns Hopkins University Distinguished Professor Barbara Starfield, M.D., M.P.H., was recognized world-wide as an expert in primary care, case mix methodologies, and promotion of equity in health. One of her profound insights was that systems of care organized around individual diseases were not optimally beneficial to patients, especially those who are chronically ill. Her defining work with patterns of morbidity forms the basis of the ACG System, which she co-developed.

Research by Prof. Starfield and her colleagues in the early 1980s showed that children using the most health care resources were not those affected by single chronic illnesses, but rather they had multiple, seemingly unrelated conditions. Prof. Starfield was able to extend these findings to all ages of patients and ultimately demonstrate that the clustering of morbidity is a better predictor of health services resource use than the presence of specific diseases.

Focusing on the patterns of morbidity forms the basis of the current ACG System and remains the fundamental concept that differentiates the ACG System from other case mix adjustment methodologies.

When Prof. Starfield passed away in 2011, the Johns Hopkins Bloomberg School of Public Health established the Barbara Starfield Scholarship Fund to support doctoral students who pursue study and research that continue Dr. Starfield’s primary areas of focus. In continuing to honor her legacy, the ACG System Team instituted The Starfield Award.

  • About the Starfield Award. LEARN MORE
  • Read more about Dr. Starfield’s life and career. LEARN MORE
  • View Dr. Starfield’s Wikipedia page. LEARN MORE


America’s first research university

Johns Hopkins University was founded on the principle that by pursuing big ideas and sharing what we learn, we make the world a better place. For more than 140 years, the university hasn’t strayed from that vision.

Intellectually Diverse

More than 21,000 undergraduate and graduate students are enrolled in the university’s nine schools.

Driven by Curiosity

For 36 years in a row, the university has put more money into research than any other U.S. academic institution.

Recognized for our Scholarship

36 Hopkins researchers past and present have earned Nobel Prizes.

Globally Focused

The university reaches into nearly every corner of the globe, conducting research, training, and related activities in more than 150 countries.


Click on a flag below for information on collaborators available in that area.


What the media is saying about us, and other important announcements the ACG System Team wants to share with you.

  • UK CCG scoops top international award.  LEARN MORE
  • CCG praised for use of population health management software. LEARN MORE
  • Johns Hopkins Takes Predictive Analytics System Global. LEARN MORE
  • Johns Hopkins ACG® System Team Honors NHS East Berkshire CCG With 2018 Starfield Award. LEARN MORE
  • Johns Hopkins Researchers Validate Using Senior Risk Factors to Predict Utilization. LEARN MORE
  • ACG System Extends Above the Arctic Circle. LEARN MORE
  • ACG System Experts Share How to Apply Big Data to Patient Care.LEARN MORE
  • Johns Hopkins Team Sees Risk Stratification Value in Rx Fill Data. LEARN MORE


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