the psychologist's index of measured intelligence as one part of a two-part determination of intelligence, the other part being an index of adaptive behavior that includes such criteria as school grades or work performance. IQ is a score, or similar quantitative index, used to denote a person's standing relative to age peers on a test of general ability, ordinarily expressed as a ratio between the person's score on a given test and the score that an average person of comparable age attained on the same test, the ratio being computed by the psychologist or determined from a table of age norms, such as the various Wechsler intelligence scales.