Two-subtest estimations of WAIS-III factor index scores

The reliability and validity of various short forms of the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; D. Wechsler, 1997) were evaluated in a sample of 100 patients with traumatic brain injury and in a demographically matched subgroup from the standardization sample. All short forms were based on 2-subtest estimations of the respective factor indexes. Although acceptable estimates could be obtained from all short forms for Verbal Comprehension, none of the possible short forms for Perceptual Organization consistently met the minimum criterion regarding the percentage of cases that fell within the 90% confidence interval of the full-length index. It is concluded that short-form estimates of the WAIS-III are not appropriate for clinical use when the goal is to obtain factor indexes.