Factor Structure of the French Adaptation of the WISC-III: Three or Four Factors?

The standardization of the French version of the Wechsler Intelligence Scale for Children-Third Edition (WISC-III) was conducted after a careful French adaptation from the U.S. version and extensive field testing. The standardization sample size was 1,120 participants with an age range from 6 years to 16 years. To check the constructive validity of the WISC-III, the same exploratory and confirmatory factor analysis than those used for the validation of the U.S. version was performed. The 4-factor solution found with the U.S. WISC-III was tested. With the French WISC-III, this solution did not fit the data and was very unstable across the age range. A 3-factor solution seemed a better one. According to the factor loadings, the 2 first factors can be called Verbal Comprehension and Perceptual Organization. Two subtests have their highest loading on the third factor: Coding and Symbol Search. This factor can be seen as a measure of the processing speed. However, further research is still needed to clarify the significance of this factor and to understand the difference we observed between the French and the U.S. factor structures.