Comparing Cattell-Horn-Carroll factor models: differences between bifactor and higher order factor models in predicting language achievement.

Previous research using the Cattell-Horn-Carroll (CHC) theory of cognitive abilities has shown a relationship between cognitive ability and academic achievement. Most of this research, however, has been done using the Woodcock-Johnson family of instruments with a higher order factor model. For CHC theory to grow, research should be done with other assessment instruments and tested with other factor models. This study examined the relationship between different factor models of CHC theory and the factors' relationships with language-based academic achievement (i.e., reading and writing). Using the co-norming sample for the Wechsler Intelligence Scale for Children--4th Edition and the Wechsler Individual Achievement Test--2nd Edition, we found that bifactor and higher order models of the subtests of the Wechsler Intelligence Scale for Children-4th Edition produced a different set of Stratum II factors, which, in turn, have very different relationships with the language achievement variables of the Wechsler Individual Achievement Test--2nd Edition. We conclude that the factor model used to represent CHC theory makes little difference when general intelligence is of major interest, but it makes a large difference when the Stratum II factors are of primary concern, especially when they are used to predict other variables.