Study Shows Misuse & Abuse of the AMA Guides

April 18, 2006

Eighty percent of all American Medical Association ratings used in reviews of permanent impairment are erroneous, with 89 percent of the erroneous ratings being elevated, according to a recent study.

According to the study, there are many causes of erroneous ratings, including bias, differences in clinical and causation assessment, and misapplication of criteria, either through lack of knowledge and skills in rating impairment, or intent. The nature of the errors is such that most erroneous ratings will be higher, rather than lower.

The national study of 2,100 impairment cases was conducted by Brigham and Associates Inc., a San Diego-based impairment assessment company.

The American Medical Association Guides to the Evaluation of Permanent Impairment, Fifth Edition are widely used in workers’ compensation, Longshore and Harbor Workers Act, automobile casualty and personal injury cases to quantify permanent losses associated with injury or illness.

This study involved the critique of 1,445 cases and the assessment of impairment on the basis of file review of 655 cases. Of AMA Guides Fifth Edition whole person erroneous ratings (839 cases of 1,037cases critiqued), the rating by the original rating physician averaged 15.5 percent whole person permanent impairment. Upon re-rating the corrected rating averaged 5.6 percent whole person permanent impairment.

Since most medical schools and residency training programs do not include instruction on the assessment of impairment, disability, or causation, many physicians lack an adequate ability to assess these and other medicolegal issues, the Brigham researchers maintain.

The study found potential rating errors resulting from inaccurate clinical or causation analysis. These include inappropriate diagnosis; rating prior to being at maximal medical improvement; using unreliable examination findings; not considering what is normal for the individual; and inaccurate causation assessment.

The goal of the AMA Guides is to provide consistent ratings, therefore reducing conflict. The AMA Guides state, “Two physicians, following the methods of the Guides to evaluate the same patient, should report similar results and reach similar conclusions.”

For more information on this study, visit

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