3M™ Clinical Risk Groups (CRGs)
Focus on a child's foot in a hospital bed
3M CRGs help identify medically complex individuals within a population.

3M CRGs can be used both to predict future health care utilization and cost and explain past health care utilization and cost.

The 3M Clinical Risk Groups (CRGs) are a population classification system that uses inpatient and ambulatory diagnosis and procedure codes, pharmaceutical data and functional health status to assign each individual to a single, severity-adjusted group.

No more "my patients are sicker than yours"

Empire BlueCross® Blue Shield® implemented 3M risk-adjustment tools and can now compare providers on an apples-to-apples basis.

Director of Reporting and Data Analysis, Empire Blue Cross Blue Shield, an Anthem Company, Rick Kresinske, speaking about CRGs

Why choose the 3M CRGs?

  • Patient-centric and clinical model
    A patient-centric and clinical model that enables change

    3M CRGs are patient-centric, focusing on the total burden of illness rather than one disease or service, and use a categorical approach to patient classification that provides clinicians with actionable data. 3M’s approach contrasts sharply with statistical models that yield regression-based risk scores that have little clinical meaning.

  • All patient populations
    Suitable for all populations

    3M CRGs were developed for use in all populations, including pediatrics. Particular attention was paid to the most complex and expensive patients across the full spectrum of age and insurance status. Among other uses, 3M CRGs are commonly used in measuring the illness burden of medically complex children.

  • Flexible

    3M CRGs are available in both prospective and retrospective models, useful for understanding both past utilization and predicting future utilization. 3M provides multiple levels of 3M CRG aggregation to fit the required level of detail. And, unlike regression-based models, the 3M CRG categorical approach allows the clinical model to remain stable while relative weights vary depending on the population, covered benefits and payer policies.

  • Risk adjustment
    Risk adjustment for important health outcomes 
    3M CRGs are closely integrated with the Potentially Preventable Admission (PPA), Potentially Preventable Emergency Department Visit (PPV) and Potentially Preventable Service (PPS) methodologies. PPAs, PPVs, and PPSs are increasingly popular ways to measure and manage potentially preventable events to improve population health.

All about 3M CRGs

3M CRGs account for clinical complexity and perform risk adjustment for individual burden of illness

3M CRGs can provide a comparative and detailed population-based understanding of disease severity, which can help you design care coordination strategies and best practices to control costs, maintain quality and improve outcomes.

  • Definition
    The 3M™ Clinical Risk Groups classification methodology describes the health status and burden of illness of individuals in an identified population. The optional 3M Functional Status Groups (FSG) methodology supplements 3M CRGs when individuals have limitations in performing the activities of daily living.
  • As a clinically credible and robust measure of individual and population health status, 3M CRGs can be used by payers, managed care organizations, hospitals, disease management and similar firms, researchers from academic and government organizations, and anyone else who seeks to understand or manage population-wide patterns of utilization, cost and quality.
  • Here are a few examples of how the 3M CRG methodology can bring value to customers.

    • Case mix adjustment in capitation payment. 3M CRGs build the foundation for fair payment to managed care organizations and other entities responsible for population health management. Because 3M CRGs are clinically based, they link the clinical and financial aspects of care. Since 2008, New York Medicaid has used 3M CRGs to adjust for case mix in managed care organization (MCO) capitation rates.
    • Risk adjustment in quality measurement and payment incentives. An increasing number of commercial and Medicaid payers measure the performance of managed care organizations, primary care practices and other entities by using 3M’s Potentially Preventable Admissions, Potentially Preventable Emergency Department Visits, and/or Potentially Preventable Services. Adjustment for differences in population health status is essential and done using 3M CRGs.
    • Tracking disease progression. 3M researchers published an analysis showing how incentives could be created to reward MCOs that do a good job managing the progression of chronic diseases over time. Separately, the Health Quality Council of Alberta used 3M CRGs to measure the progression of diabetes in the provincial population.
    • Understanding pediatric health status. 3M CRGs are a common measure of health status for children with complex health needs, as evidenced by multiple studies published in peer-reviewed journals.
    • Patient alerts at the point of care. During an office visit, some clinicians in New York state can see a dashboard that shows a patient’s current and previous 3M CRG assignment, recent potentially preventable events and identification if the patient has "persistent high needs."
    • Defining episodes. 3M CRGs are used in defining episodes of care in the 3M™ Patient-focused Episodes (PFE) Software.
  • 3M CRG grouping logic is the same for every user, although different organizations may use different versions (the most recent version is recommended). Each user makes own decisions about appropriate use, including population profiling, risk adjustment and capitation rate formulas and amounts. At this time, 3M does not offer software that emulates 3M CRG assignment and pricing used by specific payers.

    See the list of payment prediction software available for other 3M patient classification methodologies.

  • 3M CRGs are integrated with the other 3M patient classification methodologies.

    • Functional Status Groups (FSGs) can be combined with 3M CRGs to more fully describe the health status of individuals who face challenges in activities of daily living. 3M FSGs use data from the Medicare Minimum Data Set, OASIS or IRS-PAI assessment instruments to assign individuals to one of nine FSGs. 3M CRG software including FSG are licensed and provided together.
    • 3M™ Population-focused Preventables (PFP) Software uses 3M CRGs to risk adjust the incidence of PFPs across different populations, so that comparisons fairly reflect differences in population health status. The three PFPs are Potentially Preventable Admissions (PPAs), Potentially Preventable Emergency Department Visits (PPVs) and Potentially Preventable Services (PPSs).
    • 3M™ Patient-focused Episodes (PFE) Software incorporates 3M CRG information both to help define population episodes and measure a patient’s chronic disease burden at the beginning of an episode.
  • The 3M CRG Software is also at work in several 3M products, including:

    • 3M™ Core Grouping Software (CGS)
    • 3M™ Grouper Plus Content Services (GPCS)
    • 3M™ Performance Matrix Platform

    Licensees of the 3M CRG methodology can access the following documents on the 3M customer support website.

    • 3M CRG Methodology Overview
    • 3M CRG Definitions Manual
    • Summary of Changes for 3M CRG v2.1
    • 3M CRG Relative Weights (Excel spreadsheet)
    • 3M CRG Installation and User Manual (technical guide)
  • 3M experts are available to advise managed care organizations, hospitals, payers and other interested parties on how to obtain maximum value from the use of 3M CRGs. 3M consultants can also help payers design payment methods based on 3M CRGs and measure the quality of care provided by health plans, hospitals and other providers.
  • The unit of analysis is a person eligible for health care coverage. All data required to assign a 3M CRG are routinely collected by standard claims processing systems. Required data come from institutional and professional claims, i.e., the UB-04 and CMS-1500 paper forms and their corresponding X12N 837 electronic formats. When available, pharmacy data in NCPDP format are desirable.
  • The development of the 3M Clinical Risk Groups was greatly influenced by the success of Medicare payment for inpatient hospital care using the Diagnosis Related Groups (DRGs), first implemented in 1983. While the DRG unit of analysis is an inpatient hospital stay, the 3M CRG unit of analysis is an individual within an identified population. Like DRGs, the 3M CRG methodology comprises a comprehensive set of mutually exclusive and clinically coherent groups. A fundamental distinction between the two methodologies is that DRGs classify a single encounter at a point in time while 3M CRGs classify the individual and all of his or her health care services within an extended period of time.

    A second distinction is that DRGs are assigned after the services are provided, that is, retrospectively. On the other hand, 3M CRGs can be used either prospectively or retrospectively. Prospectively, the 3M CRG assignment is used to predict health care utilization costs for a period that has yet to occur. Retrospectively, the 3M CRGs are used to risk adjust for health care utilization and costs for the period that has just finished. 3M CRGs provide health care planners, managers and clinicians a meaningful basis for evaluating both the processes of care, the outcomes and the associated financial impacts.

    As a categorical clinical model, 3M CRGs differ from most other population risk-adjustment methodologies, which are statistical methods developed with regression analysis. Regression models produce a numeric score for each individual, but this score has minimal communication and management value. Regression models can do a good job explaining the past, but they do a poor job giving clinicians and managers actionable information needed to improve the future.

    3M first released 3M CRGs in 2000. The methodology was published in the prestigious journal Medical Care in 2004. In 2006, the U.S. government awarded 3M a patent for 3M CRGs. In 2008, New York state adopted 3M CRGs for use in calculating capitation payment rates to Medicaid managed care organizations (MCOs). 3M CRG v2.0 was released in 2016, and CRG v2.1 in 2018. In v2.1, there are 392 base CRG groups and approximately 1,470 total risk groups including severity levels (the count differs slightly depending on the prospective or retrospective models). For example, 3M CRG 70602 is used for a person with congestive heart failure, diabetes and chronic obstructive pulmonary disease. The first digit indicates that this person is in Health Status Group 7, Dominant Chronic Disease in Three or More Organ Systems. There are nine Health Status Groups, ranging from group 1 (healthy/nonuser) to group 9 for catastrophic conditions such as renal dialysis and major organ transplants. The next three digits (060) indicate that this patient has the combination of heart failure, diabetes and COPD, and may have other conditions as well. The final digit (2) indicates that of all the people in base 3M CRG 7060, this individual is severity 2. For most chronic base 3M CRGs, there are four or six severity levels.

    For each 3M CRG, a relative weight indicates the typical health care costs for this 3M CRG relative to the average individual in the population (given the benefits covered, utilization levels and payer policies). For example, 3M calculated a 3M CRG 70602 relative weight of 8.1364, indicating that individuals in this 3M CRG are about eight times more expensive than average. We should note that 3M CRG licensees are responsible for choosing or calculating 3M CRG relative weights are appropriate for their population and purpose. (3M consultants are available to assist licensees with 3M CRG analysis.)

    With as many as 1,470 individual 3M CRGs compared with as few as nine Health Status Groups, 3M CRGs are a very flexible tool. To enable analysts and other licensees to fit the 3M CRG methodology to their specific needs, 3M provides three levels of aggregated 3M CRGs (ACRGs). Each level provides fewer categories while maintaining key clinical detail and severity information.

    The 3M CRG clinical logic is maintained by a team of 3M clinicians, data analysts, nosologists, programmers and economists. The logic is proprietary to 3M but is available for licensees to view in an online definitions manual. The methodology is updated annually to reflect changes in the standard diagnosis and procedure code sets as well as 3M enhancements to the 3M CRG clinical logic.

Learn more about 3M CRGs

Publicly available documentation, articles and reports

Please note that documents not published by 3M do not necessarily reflect 3M recommendations and have not been approved by 3M. These documents are listed here for the information of readers interested in the various ways that 3M patient classification methodologies have been applied. Also note that listing these references does not imply endorsement of 3M methodologies by individual authors, other organizations or government agencies.

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