Exploratory and higher order factor analysis of the WJ-III full test battery: a school-aged analysis

Development of the Woodcock-Johnson (3rd ed.; WJ-III; Woodcock, McGrew & Mather, 2001a) was guided in part by Carroll's (1993) 3-stratum theory of cognitive abilities and based on confirmatory factor analysis (CFA), even though Carroll used exploratory factor analysis (EFA) to derive his theory. Using CFA, McGrew and Woodcock (2001) found a 9-factor model across all age ranges. To determine if the 9-factor structure holds for the full WJ-III battery, we applied currently recognized best practices in EFA to 2 school-aged 42-subtest correlation matrices (ages 9–13 and 14–19 years). Six factors emerged at the 9–13 age range, while 5 factors were indicated at the 14–19 age range. The resulting 1st-order factors displayed patterns of both convergence with and divergence from the WJ-III results presented in the Technical Manual. These results also revealed a robust manifestation of general intelligence (g) that dwarfed the variance attributed to the lower order factors. It is surprising that this study represents the first time the WJ-III full battery was subjected to EFA analyses given the instrument's significant use by practitioners and that it served as the initial evidentiary basis for Cattell-Horn-Carroll (CHC) theory. The lack of confirmation of CFA results with EFA methods in the current study permits questioning of the structure of the WJ-III and its relationship with CHC theory. Additional independent, structural analyses are clearly indicated for the WJ-III full test battery before we can be confident in its structure.