Impairment rating ambiguity in the United States: the Utah Impairment Guides for calculating workers' compensation impairments

Abstract

Since the implementation of workers' compensation, accurately and consistently rating impairment has been a concern for the employee and employer, as well as rating physicians. In an attempt to standardize and classify impairments, the American Medical Association (AMA) publishes the AMA Guides ("Guides"), and recently published its 6th edition of the AMA Guides. Common critiques of the AMA Guides 6th edition are that they are too complex, lacking in evidence-based methods, and rarely yield consistent ratings. Many states mandate use of some edition of the AMA Guides, but few states are adopting the current edition due to the increasing difficulty and frustration with their implementation. A clearer, simpler approach is needed. Some states have begun to develop their own supplemental guides to combat problems in complexity and validity. Likewise studies in Korea show that past methods for rating impairment are outdated and inconsistent, and call for measures to adapt current methods to Korea's specific needs. The Utah Supplemental Guides to the AMA Guides have been effective in increasing consistency in rating impairment. It is estimated that litigation of permanent impairment has fallen below 1% and Utah is now one of the least costly states for obtaining workers' compensation insurance, while maintaining a medical fee schedule above the national average. Utah's guides serve as a model for national or international impairment guides.

Keywords: AMA Guides; AMA Impairment; Ambiguity; Disability; Impairment; Permanent Partial Disability; Permanent Partial Impairment; Workers' Compensation.

Fig. 1

This figure demonstrates injury recovery for an individual who shows no signs of impairment. The left-hand coordinate measures the percentage of total body impairment, with the abbreviation imp representing impairment. The right-hand coordinate measures time. An injured individual may show impairment at the time of the injury, but after a recovery period may show no signs of impairment.

Fig. 2

This figure demonstrates injury recovery for an individual who shows permanent impairment. The left-hand coordinate measures wellness or impairment, with the abbreviation imp representing impairment. The right-hand coordinate measures time. The recovery path from Fig. 1 is shown in comparison to a patient who plateaus in their recovery period at less than 100% wellness. The difference between the patient's plateau and 100% wellness is defined as impairment.

Fig. 3

This figure demonstrates the impact of impairment on an individual's career opportunities. The impairment serves as a baseline measurement of impaired function, but the true impact of impairment depends on the other factors listed on top of the impairment foundation. An individual with limited education and geographical opportunities will be much more affected by impairment than an individual with extensive education who lives in a metropolitan area.

Fig. 4

This figure demonstrates the State of Utah's average costs per 100,000 workers related to permanent partial impairment in comparison to several other states in the western United States. The left-hand coordinate measures total costs in millions of U.S. dollars. The right-hand coordinate represents individual states. UT, Utah; CA, California; CO, Colorado; MT, Montana; NV, Nevada, NM, New Mexico; OR, Oregon; REG AVG Ex CA, Regular average excluding California; CW, weighted average of states excluding california.