Dimensional Structure of the Wais-R: A Simultaneous Multi-Sample Analysis

A two-step procedure was used to evaluate the dimensional structure of the WAIS-R. The first step involved the assessment of the goodness-of-fit of various one, two, and three factor models of the WAIS-R, by using confirmatory factor analytic procedures, for a sample of Anglo adults (n = 200). A three-common-factor solution provided the best fit for the Anglo sample data: Verbal Comprehension, Perceptual Organization, and Freedom from Distractability. Using the just cited model, the second step employed a simultaneous multi-sample confirmatory factor analysis and evaluated the equality of factor solutions for the Anglo sample and an additional sample of Mexican-American adults (n =200). The factor solutions were found to be invariant across the two samples. Implications for the assessment of abilities underlying performance on the WAIS-R are discussed.