Joint Factor Structure of the WISC-R and K-ABC for Referred School Children

Abstract

The K-ABC has been the focus of considerable research and controversy, much of which has focused on understanding the constructs measured by this new test. Factor analyses of the K-ABC have found support for the test as a measure of simultaneous and sequential mental processing and achievement, but also have supported alternative interpretations, such as nonverbal reasoning, verbal memory, and verbal reasoning. The present study examined further the factorial validity of the K-ABC through joint factor analysis with the WISC-R. Of particular interest were several of the WISC-R subtests that should load differently if the K-ABC simultaneous/sequential model were valid than if an alternative interpretation were valid. Results were somewhat more supportive of a nonverbal reasoning/verbal memory interpretation of the K-ABC, but either interpretation could be supported by this research. The present study was less supportive of the K-ABC Achievement scale as a measure of school achievement. The K-ABC Achievement scale split into two factors: Reading achievement and verbal reasoning (with the WISC-R Verbal subtests). When analyzed with both the WISC-R and the WRAT, the K-ABC Reading subtests joined the WRAT tests on an achievement factor; the remaining K-ABC “achievement” tests loaded on a separate verbal reasoning factor with the WISC-R Verbal tests. Finally, the unrotated factor solutions support the notion of the K-ABC g factor as a measure of general intelligence rather than general achievement.