Re(Examining) Relations between CHC Broad and Narrow Cognitive Abilities and Reading Achievement

Previously, Evans and colleagues (2001) utilized simultaneous multiple regression to examine relations between Cattell-Horn-Carroll (CHC; Schneider & McGrew, 2012) broad and narrow cognitive abilities and reading achievement across the school age span. Although their findings suggest that many broad/narrow abilities had clinically significant effects on reading achievement they failed to account for the potential moderating effects of the general factor. To account for these effects, the current study employed hierarchical multiple regression analysis to reexamine the relationships between CHC dimensions and reading achievement after controlling for the effects of the general factor with 4,722 participants ages 6-18 from the Woodcock Johnson III Psychoeducational Battery (WJ III; Woodcock, McGrew, & Mather, 2001a). Results from the present study indicate that the full scale GIA composite (as a proxy for g) consistently accounted for large effects across the school age span for all of the reading achievement variables that were assessed. Among the broad and narrow abilities, only Gc consistently accounted for meaningful proportions of reading scores beyond g. As a consequence, researchers are encouraged to give greater consideration to the dimensionality of broad and narrow CHC measures when examining cognitive-achievement relationships or they may risk over-interpreting the predictive effects associated with these indices. Potential implications for clinical application of CHC theory are also discussed.