title: Interpretation of KABC-II scores: An evaluation of the incremental validity of Cattell-Horn-Carroll (CHC) factor scores in predicting achievement.
abstract: This study is an examination of the incremental validity of Cattell-Horn-Carroll (CHC) factor scores from the Kaufman Assessment Battery for Children-second edition (KABC-II) for predicting scores on the Kaufman Test of Educational Achievement-second edition (KTEA-II). The participants were children and adolescents, ages 7-18, (N = 2,025) drawn from the KABC-II standardization sample. The sample was nationally stratified and proportional to U.S. census estimates for sex, ethnicity, geographic region, and parent education level. Hierarchical multiple regression analyses were used to assess for factor-level effects after controlling for the variance accounted for by the full scale Fluid-Crystallized Index (FCI) score. The results were interpreted using the R2/ΔR2 statistic as effect size indices. Consistent with similar incremental validity studies, the FCI accounted for statistically and clinically significant portions of KTEA-II score variance, with R2 values ranging from .30 to .65. KABC-II CHC factor scores collectively provided statistically significant incremental variance beyond the FCI in all of the regression models, although the effect size estimates were consistently negligible to small (Average ÄRCHC2 = .03). Individually, the KABC-II factor scores accounted for mostly small portions of achievement variance across the prediction models, with none of the individual CHC factors accounting for clinically significant incremental prediction beyond the FCI. Additionally, most of the unique first-order predictive variance was captured by the Crystallized Ability factor alone. The potential clinical and theoretical implications of these results are discussed.
authors.affiliation: Department of Psychology and Philosophy.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: McGill
mesh_terms: D000124:Achievement; D000293:Adolescent; D002648:Child; D004521:Educational Measurement / Q000592:standards*; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007361:Intelligence Tests / Q000592:standards*; D008297:Male; D012015:Reference Standards; D015203:Reproducibility of Results