Exploratory and Hierarchical Factor Analysis of the WJ-IV Cognitive at School Age
Exploratory and confirmatory factor analytic studies were not reported in the Technical Manual for the Woodcock-Johnson, 4th ed. Cognitive (WJ IV Cognitive; Schrank, McGrew, & Mather, 2014b) Instead, the internal structure of the WJ IV Cognitive was extrapolated from analyses based on the full WJ IV test battery (Schrank, McGrew, & Mather, 2014b). Even if the veracity of extrapolating from the WJ IV full battery were accepted, there were shortcomings in the choices of analyses used and only limited information regarding those analyses was presented in the WJ IV Technical Manual (McGrew, Laforte, & Shrank, 2014). The present study examined the structure of the WJ IV Cognitive using exploratory factor analysis procedures (principal axis factoring with oblique [promax] rotation followed by application of the Schmid–Leiman, 1957, procedure) applied to standardization sample correlation matrices for 2 school age groups (ages 9–13; 14–19). Four factors emerged for both the 9–13 and 14–19 age groups in contrast to the publisher’s proposed 7 factors. Results of these analyses indicated a robust manifestation of general intelligence (g) that exceeded the variance attributed to the lower-order factors. Model-based reliability estimates supported interpretation of the higher-order factor (i.e., g). Additional analyses were conducted by forcing extraction of the 7 theoretically posited factors; however, the resulting solution was only partially aligned (i.e., Gs, Gwm) with the theoretical structure promoted in the Technical Manual and suggested the preeminence of the higher-order factor. Results challenge the hypothesized structure of the WJ IV Cognitive and raise concerns about its alignment with Cattell-Horn-Carroll theory.