Confirmatory factor analysis of the WPPSI for language-impaired children

The present study used a maximum-likelihood confirmatory factor analysis (CFA) to test the hypothesis that a four-factor model is the most parsimonious explanation of the structure of the WPPSI for language-impaired children. Four separate maximum-likelihood confirmatory factor analyses were performed on a sample of 198 Norwegian language-impaired children tested with the WPPSI, and on the Norwegian (n = 563) and American (n = 1200) standardization samples. A one-factor (general), a two-factor (verbal and performance), three-factor (parallel to the WISC-R) and a four-factor solution composed of "processing dependent" ("knowing how" and "seeing how") and "knowledge dependent" ("knowing that" and "seeing that") were imposed on the average intercorrelation matrices of the 11 WPPSI subtests. Confirmatory factor analysis indicated that the four-factor latent construct model was the most parsimonious explanation of the structure of the WPPSI for language-impaired children, as well as for normally developing children.