APA Dictionary of Psychology

a system of evaluating the presence and severity of clinical psychiatric signs on the basis of 24 factors, such as bizarre behavior, hostility, emotional withdrawal, and disorientation. Each factor is rated on a 7-point scale ranging from not present to extremely severe, based on the judgments of trained observers. [introduced in its original version in 1962 by U.S. psychiatrist John E. Overall and U.S. clinical psychologist Donald R. Gorman]