The Hierarchical Factor Structure of the WISC-R for Learning Disabled Children

A Wherry and Wherry (1969) hierarchical factor solution was performed on the 12 WISC-R subtest intercorrelations for a sample of 85 learning disabled children. A hierarchical ability structure similar to, though not congruent with, Vernon's (1950) paradigm was obtained. The hierarchy included a general (g) factor and three subgeneral factors consisting of an intact spatial-perceptual-mechanical (k:m) factor, a verbal comprehension factor, and a freedom-from-distractibility factor. The factor structure of learning disabled children was somewhat more fractionated and complex than that for normals, but not as complex as the structure of reading disabled children. This suggests that the more severe a learning disability, the greater the difference between the hierarchical factor structure for that group and the factor structure of normals.