The Global Assessment of Functioning (GAF) is part five of the multiaxial diagnostic system for mental disorders outlined in the Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition–Text Revised (DSM-IV-TR). The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) notes the use of DSM-IV-TR in rating an individual's global functional capacity, which, like disability, is related directly to the effects of impairments. The AMA Guides, Fourth and Fifth Editions, do not provide numeric psychiatric impairment, and shortcomings plague the use of GAF to define disability—but even so, authorities ranging from the State of California to the Veterans Administration rely on GAF scores. A table shows the 100-point scale Global Assessment Scale in which higher scores indicate better functioning. The GAF has been modified to address deficiencies; a decision tree has been added and is summarized; and the editor of DSM-IV-TR has developed a computerized version that reportedly improves reliability and validity. Evaluators should bear in mind that the GAF helps evaluate the individual's functioning in three areas: psychological, social, and occupational (including the activities of daily living). The resulting score facilitates the creation of a treatment plan, evaluates its effectiveness, and predicts outcomes, but evaluators should be aware of its significant limitations.