An impairment rating evaluation is a medical evaluation of permanent impairment based on American Medical Association (AMA) "Guides to the Evaluation of Permanent Impairment." An impairment rating based on AMA guides is used to measure the severity of impairment of an individual and how that impairment affects the individual’s quality of life and the ability to perform daily activities.

An individual affected by a permanent impairment may have any number of problems functioning in daily life activities. Daily activities affected can range from sitting, standing, or walking impairments to the basic inability to care for one’s own hygiene (such as brushing one’s teeth or combing one’s hair). Whatever the impairment or impairments, an impairment rating evaluation is a tool used to help measure the degree of diminished capacity in performing daily living activities.

The American Medical Association published its first impairment rating article in 1958. The first article focused on evaluating impairment of the back and extremities. Several more articles on impairment evaluation followed in the 1960s, and in 1971 the American Medical Association published its first "Guides to the Evaluation of Permanent Impairment," a compendium of its first 13 articles. The sixth edition is now in print. Most states use the AMA Guides but not every state uses the same or most current edition.

An impairment rating can range from a class 0, no impairment, to a class 4, very severe impairment. When an individual becomes impaired, whether through the everyday workplace environment, military service, an accident, or other onset such as toxic exposure, it is important that they get the proper diagnosis and the medical care they need to recover. If they are not able to fully recover, they reach a point of maximum medical improvement, whereby they have some permanent impairment that will not improve further, with or without continued medical care.

Individuals facing permanent impairment should undergo an impairment rating evaluation to determine the degree by which their ability to perform their daily living activities has been diminished by their impairment. An evaluation can help provide the proper support for insurance settlements or worker’s compensation claims.

It is important to receive an impairment rating evaluation by an independent physician who is qualified and experienced in impairment rating evaluations. An independent physician can provide an unbiased opinion of the medical records and an unbiased assessment of the level of impairment(s). Ultimately, having an independent physician helps to provide the clearest picture of the level of impairment of an individual.

A physician evaluator should, at the very least, be a certified examiner by the AMA Guides. A physician evaluator certified and with experience will provide the best explanations of his findings and conclusions, with specific citations to the AMA Guides. Evaluations prepared by an expert and that include specific support for their findings are the most likely to prevail. An expert evaluator is a certified rater who has had years of experience in impairment rating work.