title: Wechsler Intelligence Tests: do we really have a criterion of mental retardation?
abstract: The definition of mental retardation offered by the American Association on Mental Deficiency refers to an IQ of approximately 70 or below. This is identical to the Wechsler criterion of a test performance two standard deviations (SDs) below the population mean. In fact, Wechsler tests have not supplied such a criterion, rather they have deviated from it by anything from .27 to a full SD. Having done without such a criterion for 40 years, we should consider exchanging it for one that is fixed in time and whose external validity is attested to by an accumulated body of evidence.
mesh_terms: D002648:Child; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis*; D007360:Intelligence; D011594:Psychometrics; D014888:Wechsler Scales