Stability of the WPPSI-R and WISC-III Factor Structure Using Cross-Validation of Covariance Structure Models

Abstract

The reliability of the Verbal Comprehension and Perceptual Organization factors of the WPPSI-R and WISC-III was examined by use of cross-validation of covariance structure models, a new statistical methodology that employs both unrestricted and restricted factor analyses. Reliability of the factor structure would be indicated if the goodness of fit of restricted factor analytic models generated from unrestricted factor patterns did not degrade when tested on other age groups. If the goodness of fit changed in an inconsistent fashion, that would indicate that the factor structure of one or both of the instruments is unreliable. Finally, if the goodness of fit changed in a systematic fashion, getting worse with greater age differences, then an argument for true intellectual changes could be made. Results revealed general consistency in the goodness of fit across age groups. Therefore, it was concluded that a two-factor model that consists of the Verbal Comprehension and Perceptual Organization factors is reliable across age groups and instruments.