Controversy attends use of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) in defining injured workers’ permanent partial disability benefits: States desire an efficient, nonsubjective way to determine benefits for nonscheduled injuries and are using the AMA Guides to define the extent of disability. Organized labor is concerned that use of the AMA Guides, particularly with modifications, does not yield a fair analysis of an injured worker's disability. From its first issue, The Guides Newsletter emphatically emphasized and clearly stated that impairment percentages derived according to AMA Guides criteria should not be used to make direct financial awards or direct estimates of disability. The insurance industry and organized labor differ about the use of the AMA Guides in defining permanent partial disability (PPD). Insurers support use of the AMA Guides because they seek a uniform system that minimizes subjectivity in determining benefits. Organized labor is particularly concerned about the lack of fairness of directly equating impairment and disability, and if the rating plays a role in defining disability, additional issues also must be considered. More states are likely to use the AMA Guides with incorporation of additional features such as an index to PPD.