Correlational and factor analysis of the Peabody Individual Achievement Test and the WISC-R

Factor analyzed subtest scores from the Peabody Individual Achievement Test (PIAT) and the WISC-R for 180 6-17 yr olds to determine the number and kinds of factors measured by the PIAT. Two factors were found when the PIAT was factored alone. Reading Recognition, Reading Comprehension, and Spelling loaded highly on a Word Recognition factor, whereas Mathematics and General Information had moderate to high loadings on a School-Related Knowledge factor. When the PIAT was factored with the WISC-R subtests, a Word Recognition factor was found in addition to the 3 factors usually reported for the WISC-R. The School-Related Knowledge factor of the PIAT was subsumed by the other factors. General Information loaded highly on the Verbal Comprehension factor, and Mathematics loaded highly on the Freedom from Distractibility factor. Implications for the interpretation of the PIAT are discussed.