Validity of demographically corrected norms for the WAIS-III

The diagnostic validity of new demographically corrected WAIS-III norms was investigated using a sample of 100 patients with traumatic brain injury (TBI) and a matched control group from the standardization sample. Demographically corrected norms were compared to traditional age-corrected norms. Although education accounted for incremental variance in WAIS-III factor scores in patients with TBI, above and beyond the effects of injury severity, the demographically corrected norms did not yield statistically different diagnostic classification of individuals with moderate-severe TBI than the traditional norms. In participants with relatively low levels of educational attainment, sensitivity to length of coma was less for demographically corrected norms then for traditional age-corrected norms. Nevertheless, when using a discrepancy between Verbal Comprehension and Processing speed, diagnostic accuracy rates were again similar for both sets of norms. It is concluded that the demographically corrected WAIS-III norms do not offer a clear advantage or disadvantage compared to traditional age-corrected norms in the assessment of patients with TBI who are Caucasian and who have at least a middle school level of education.