Structural validity of the Woodcock Johnson III Cognitive in a referred sample

The structural validity of the WJ-III Cognitive was investigated using the GIA-Extended Battery test scores of 529, six-to-thirteen-year-old students referred for a psychoeducational evaluation. The results of an exploratory factor analysis revealed 11 of the 14 tests loaded on their expected factors. For the factors Gc, Gf, Gs, and Gv, both tests associated with the factor loaded highly; for Gsm, Glr, and Ga, only one test associated with each factor loaded highly. Obtained congruence coefficients supported the similarity between the factors Gs, Gf, Gc, Glr, and Gv for the current referred sample and the normative factor structure. Gsm and Ga were not found to be similar. The WJ-III Cognitive structure established in the normative sample was not fully replicated in this referred sample. The Schmid-Leiman orthogonalization procedure identified a higher-order factor structure with a second-order, general ability factor, g, which accounted for approximately 38.4% of common variance and 23.1% of total variance among the seven, first-order factors. However, g accounted for more variance in both associated tests for only the orthogonal first-order factor Gf. In contrast, the Gc and Gs factors accounted for more variance than the general factor for both of their respective tests. The Gsm, Glr, Ga, and Gv factors accounted for more variance than g for one of the two tests associated with each factor. The outcome indicates Gc, Gf, Gs, and Gv were supported and thus are likely factors that can be utilized in assessment while Gsm, Glr, and Gr were not supported by this study. Additionally, results indicate that interpretation of the WJ-III scores should not ignore the global ability factor.