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State-by-State Use of AMA Guides

July 23, 2019 (11 min read)

Origins and Development of AMA Guides

Ever since humans were nomadic hunter-gatherers, some members of the tribes inevitably would be injured or disabled from accidents, battles, or diseases. Surely many were left for dead, but one element that separated humans from all other species was the emergence of a moral imperative to care for the sick and wounded, and an evolving sense of social justice. Over the millennia, various methods to help and eventually compensate the disabled developed.

The American Medical Association was instrumental in supporting early research and medical education to help its physician members evaluate and treat impaired and disabled patients. In 1958, it published a seminal article entitled, “A Guide to the Evaluation of Permanent Impairment of the Extremities and Back.” (AMA, 1958). Its positive reception led to other body parts and organ systems receiving similar thorough analysis, until a compendium of 13 guides were published as a complete book, which became the first edition of the AMA Guides to the Evaluation of Permanent Impairment in 1971. Since that time, it has been refined five more times, resulting in the recent release of the Sixth Edition of the AMA Guides (Rondinelli, 2008). It has become the international gold standard publication that incorporates the most updated clinical and scientific knowledge for the objective, evidence-based evaluation of impairment in individuals.

For a chart of state-by-state use of the AMA Guides, see the PDF at the end of this article.

States Adopting AMA Guides in Workers’ Compensation Claims

As the AMA Guides became more widely used and supported, the great disparity among the various states and jurisdictions in terms of permanent partial disability awards became clear. In the interest of fairness, the National Commission on State Workmen’s Compensation Laws in 1972 called for more consistent application of guidelines on impairment, such as the first edition of the AMA Guides that had just been released at the time. Asking medical evaluators of impaired individuals to use standardized nomenclature and methodology would reduce the jurisdictional disparity, ease the adjudicative burden of administrative bodies charged with dispensing the benefits to impaired people, and potentially decrease the complexity of litigation.

As the wisdom of a more systematic, reproducible approach became evident, several of the states legislatively adopted the use of the AMA Guides as the required methodology to determine the level of medical impairment, thus enabling the benefits administrator to determine the level of disability and subsequent award to the claimant. Some states specified the edition number in the statute or regulation, thus not allowing for subsequent releases of new editions to be incorporated into that state’s system without new legislation being passed. While this enables all parties in cases to become familiar with the AMA Guides used in that jurisdiction, it does not allow for the tremendous pace of scientific advancement and evidence-based knowledge to be applied to claims in those states. Other state statutes or regulations specify that the most current edition of the AMA Guides is to be used in that jurisdiction, thus not requiring future legislation to coincide with edition updates. However, this requires all parties to workers’ compensation claims in those jurisdictions to quickly familiarize themselves with each new edition of the AMA Guides to stay current. In addition, the statutory adoption of a future edition of a document that has not yet been conceived or written has been challenged on the grounds that it is an unconstitutional delegation of legislative authority (McFarren 2008). The Supreme Court of Pennsylvania, in a split decision, held that the provision in the state’s Workers’ Compensation Act [77 P.S. § 511.2(1)] requiring physicians to apply the methodology set forth in “the most recent edition” of the AMA Guides violates the state’s constitutional requirement [see Pa. Const. art. II, § 1] that all legislative power “be vested in a General Assembly” [see Protz v. Workers’ Comp. Appeal Bd. (Derry Area Sch. Dist.), 2017 Pa. LEXIS 1401 (June 20, 2017); for an extensive discussion of Protz].

Almost 20 states developed some form of their own impairment rating system. Some of these state-specific rating systems (e.g., North Carolina) have a very limited range and scope to so-called scheduled conditions, and even suggest that in cases where the state-specific ratings guide does not address the situation adequately, the physician evaluator should also refer to the AMA Guides for a final determination.

In addition to the state adoption of the AMA Guides for workers’ compensation claims, federal employee workers’ compensation cases under the Federal Employees Compensation Act (FECA) or the Longshore and Harbor Workers’ Compensation Act employ the AMA Guides for the determination of impairment. Several Canadian provinces and jurisdictions in New Zealand and Australia rely on the AMA Guides to adjudicate workers’ compensation claims, motor vehicle accident personal injury claims, and other disability benefit systems. Another key factor that is likely to continue to increase the worldwide influence and use of the AMA Guides was its sixth edition editors’ deliberate adoption of the terminology and conceptual framework of “disablement,” as developed by the World Health Organization’s International Classification of Functioning, Disability and Health (ICF) (WHO, 2001). In an increasingly global marketplace, this will support the movement toward a global standard and expectation of fairness in claim resolution.

Differences Between the Editions

The AMA Guides have evolved significantly over six different editions spanning nearly four decades. Because different medical editorial boards were responsible for the planning and composition of the various editions, they tended to have a different style and context. Each was designed to reflect the most current scientific and clinical knowledge on each body part or organ system at the time. For example, the fourth edition introduced a chapter on pain issues, and the concept of Diagnosis-Related Estimates (DREs) for the determination of spinal impairment cases. The fifth edition expanded the range of motion (ROM) method of rating, especially for spinal impairment evaluations.

The newest edition attempts to address several criticisms of the previous editions, including a lack of internal consistency that would lead different examiners to arrive at discordant impairment ratings for the same claimant, and a lack of an accurate relationship between the impairment and true loss of function. In addition to adopting the ICF terminology, the editorial board of the sixth edition claims to have focused on evidence-based diagnoses, simplification to improve inter-rater reliability, congruity between different organ system rating methodologies, and a focus on function-based rating. In this regard, the ROM method of spinal evaluation is essentially eliminated in the sixth edition, and the DRE methodology was expanded into a new Diagnosis-Based Impairment (DBI) terminology.

The sixth edition adopts a generic template for impairment grids across the various organ systems that generally includes five impairment classes, an impairment rating percentage range, and impairment criteria that can vary the result, such as history, physical examination, and objective test results. In select situations, the personal functional history and burdens of treatment compliance are also used to modify the final impairment value.

Use of AMA Guides for Medical Evaluations

Distinction Between Impairment and Disability

A key issue in the determination of a person’s functional capacity and eligibility for benefits payments is the distinction between impairment, and the potential resulting disability that may extend from the impairment. The relationship between the two is both theoretically and practically difficult to disentangle, but has major implications for the resolution of a claim. It also helps identify the persons or organizations capable of and responsible for making these determinations. The AMA Guides Sixth edition uses the following two definitions to lay the groundwork for this distinction:

Impairment: a significant deviation, loss, or loss of use of any body structure or body function in an individual with a health condition, disorder or disease.

Disability: activity limitations and/or participation restrictions in an individual with a health condition, disorder or disease.” (AMA 2008, p. 5)

The measurement and rating of impairment involves the scientific and clinical assessment of the functioning of the body parts or organ systems in question and the causal relationship to the exposure or event, which is typically the domain of specially-trained physicians to derive the impairment. The translation of impairment into a level of disability or disablement involves broader input to determine the degree of functional loss in that specific person’s mobility and activities of daily living (ADLs). These are put in the context of the claimant’s physical, psychological, psychosocial, vocational and non-work-related factors. This is more appropriately an administrative and adjudicative function in the domain of the insurance company, workers’ compensation carrier, or disability board depending on the type of claim at hand.

The language of these two critical definitions has been changed in the sixth edition from previous editions. Some commentators have been critical of this change, which added the word “significant” at the beginning of the definition of impairment, and changed the prior definition of disability in the fifth edition: “alteration of an individual’s capacity to meet personal, social or occupational demands or statutory or regulatory requirements because of an impairment” (Cocchiarella 2000).

When to Evaluate Permanent Impairment

As is implied in the very title of the AMA Guides to the Evaluation of Permanent Impairment, they are intended only to be applied and used to construct impairment ratings when the injury or illness is considered to be permanent by the treating physicians. This typically requires that the claimant has reached the status of “Maximum Medical Improvement (MMI).” MMI is reached after sufficient time has passed for healing and recovery expected to occur from the treatment methodology chosen. This does not, of course, imply that there has been complete resolution of the symptoms or condition, but rather that all reasonable medical treatment has been offered and it has reached an effective clinical plateau beyond which significant improvement or decline is not anticipated.

There is no standard or arbitrary time limit, but rather is highly individualized depending on the diagnosis and factors specific to the claimant, and may range from days to months or beyond. However, the AMA Guides should not be used until MMI has been reached, and not during active treatment and recovery of temporary conditions. For example, the Guides should not be used to determine what work restrictions may be appropriate to keep a worker safe and comfortable to perform his usual job duties.

Process for Evaluating Impairment

The basic process followed by physicians performing an impairment rating is clearly explained to raters in each edition of the AMA Guides. Essentially, the physician is asked to perform a history and physical examination to assure that the person is at MMI. Then she should establish a reliable evidence-based diagnosis from the information available, and decide which impairment criterion is considered the “key factor.” In the current sixth edition, the rater should use the appropriate regional grid supplied in the chapters to arrive at the impairment class (numerical value from 0 to 4) for the condition being rated at MMI. The range within each impairment class can be divided into 5 impairment grades (letters A to E). Then the adjustment grids are applied for the applicable modifiers such as the other impairment criteria considered non-key factors. This information is combined to arrive at the numerical impairment rating for the specific impairment class and grade. If somehow the Guides provide more than one method to rate a particular impairment, the method producing the higher impairment rating is used. Finally, the appropriate whole person impairment (WPI) value is calculated by combining the ratings from different organ systems.

The books supply easy-to-follow tables, graphs and grids for each organ system. The physician rater should supply the requesting organization a valid impairment evaluation report that clearly documents the rater’s review of prior medical and treatment records, clinical evaluation, analysis of the findings, and a discussion of how the final impairment rating was calculated. The impairment evaluation and its resultant report essentially serve as the rating physician’s expert testimony to help adjudicate the claim.


American Medical Association, Guides to the Evaluation of Permanent Impairment. Chicago, Ill.: American Medical Association, 1971.

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision. American Psychiatric Association, 2000.

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. American Psychiatric Association, 2013.

Brown v. Campbell Bd. of Educ., 915 S.W.2d 407 (Tenn. 1995).

Cocchiarella L, Andersson GBJ. Guides to the Evaluation of Permanent Impairment. 6th ed. Chicago, Ill.: American Medical Association, 2000.

Davis v. B.F. Goodrich, 826 P. 2d 587 (Okla. 1992).

McCabe v. North Dakota Workers Compensation Bureau, 1997, ND 145, 567 N.W.2d 201

McFarren TD. AMA Guides, Sixth Edition Arrives on the Scene, reprinted on the LexisNexis Legal Newsroom Workers’ Compensation at

Rondinelli RD, Genovese E, Katz RT, Mayer TG, Mueller K, Ranavay M, Brigham CR., eds. Guides to the Evaluation of Permanent Impairment. 6th ed. Chicago, Ill.: American Medical Association, 2008.

Seabury, Seth A. PhD, Frank Neuhauser, MPP, and Teryl Nuckols, MD, MSHS, “American Medical Association Impairment Ratings and Earnings Losses Due to Disability,” Journal of Occupational and Environmental Medicine, Vol. 55 No. 3, pp. 286–291 (March 2013).

Spieler EA, Barth PS, Burton JF Jr., Himmelstein J, Rudolph L, Recommendations to Guide Revision of the Guides to the Evaluation of Permanent Impairment, JAMA 2000;283 (4) 519–523.

Texas Workers’ Compensation Comm’n. v. Garcia, 893 S.W.2d 504 (Tex. 1995).

World Health Organization. International Classification of Functioning, Disability and Health: ICF. Geneva, Switzerland: World Health Organization, 2001.

© Copyright 2019 LexisNexis. All rights reserved. This article was excerpted from Occupational Injuries and Illnesses (LexisNexis).