Theoretical Foundations of the Wj-R Measures of Cognitive Ability

The WJ-R provides a wide age range and comprehensive set of cognitive measures. A major interpretation feature of the battery is the provision of eight factor scores, each based on two measures. The theoretical basis for the tests is founded in Gf-Gc theory, work that is often associated with Raymond Cattell and John Horn, although other scholars think and write about intelligence in a similar vein. This report is a brief review of the theory followed by the results of several factor analytic studies. Nine data sets drawn from the 1977 and 1989 norming and concurrent validity studies have been analyzed. In the concurrent studies, the WJ-R cognitive tests were administered in conjunction with other major batteries including the K-ABC, the SB-IV, the WISC-R, and the WAIS-R. Altogether, 15 sets of exploratory and confirmatory factor analyses that included a total of 68 variables were completed. The results of all studies provide support for the WJ-R eight-factor model of Gf-Gc theory. As a byproduct of the procedure, comparative information was observed for the congruence of other cognitive batteries to the Gf-Gc theory. It is suggested that the other cognitive batteries often have been underfactored, which has led to misinterpretation of their factorial structures. This report demonstrates the need for factor analytic studies in which the set of variables is not constrained to the limited set of subtests that have been published together as a battery. It is indicated that the set of variables to be included in a factor study must include enough breadth and depth of markers to ensure that the presence of all major factor effects can be identified.