Factor Replication of the WISC-III in Three Independent Samples of Children Receiving Special Education

This study examined the first-order factor structure of the Wechsler Intelligence Scale for Children-Third Edition (WISC-III; Wechsler, 1991) on three samples of children previously diagnosed with a handicapping condition. Five alternative factor models were compared through confirmatory factor analysis. Previous factor analytic studies that focused on the WISC-III's four-factor solution employed all 13 subtests in their analyses, despite the fact that only 12 subtests are combined during clinical evaluations to obtain scores on the four factors. This study investigated the WISC-III factor structure by considering the 12 subtests that actually combine to yield index scores on the dimensions of Verbal Comprehension, Perceptual Organization, Processing Speed, and Freedom from Distractibility. Results support a four-factor solution for children with disabilities.