Broad cognitive abilities of children with mental retardation: an analysis of group and individual profiles.

Group and individual broad ability profiles of children with mental retardation and a matched sample of children with average achievement was investigated through use of the 7 Cattell-Horn-Carroll (CHC) factor clusters from the Woodcock-Johnson III Tests of Cognitive Abilities. Results indicate that, as a group, the ranked performance of the children with mental retardation on the CHC factor clusters was largely consistent with the clusters' g loadings. When compared to average-achieving matches, the children with mental retardation scored lower on all CHC factor clusters, but the groups displayed different patterns of performance. Despite normative deficiencies in IQs, children with mental retardation demonstrated a wide range of performance across measures. Implications for assessment and diagnosis are discussed.