Standardization[edit]
The WAIS-IV was standardized on a sample of 2,200 people in the United States ranging in age from 16 to 90.[10] An extension of the standardization has been conducted with 688 Canadians in the same age range.
Age range and uses[edit]
The WAIS-IV measure is appropriate for use with individuals aged 16–90 years. For individuals under 16 years, the Wechsler Intelligence Scale for Children (WISC, 6–16 years) and the Wechsler Preschool and Primary Scale of Intelligence (WPPSI, 2½–7 years, 7 months) are used.
Intelligence tests may be utilized in populations with psychiatric illness or brain injury, in order to assess level of cognitive functioning, though some regard this use as controversial[who?]. Rehabilitation psychologists and neuropsychologists use the WAIS-IV and other neuropsychological tests to assess how the brain is functioning after injury. Specific subtests provide information on a specific cognitive function. For example, digit span may be used to get a sense of attentional difficulties. Others employ the WAIS-R NI (Wechsler Adult Intelligence Scale-Revised as a Neuropsychological Instrument), another measure published by Harcourt. Each subtest score is tallied and calculated with respect to neurotypical or brain-injury norms. As the WAIS is developed for the average, non-injured individual, separate norms were developed for appropriate comparison among similar functioning individuals.