Joint factor analysis of the K-ABC and McCarthy Scales

A joint-factor analysis was conducted using three major scales of the McCarthy Scales of Children's Abilities and eight Kaufman-ABC subtests as variables. Subjects were 90 children ages 4 to 8 1/2 yr. The scree test produced three significant factors, each interpretable from the Kaufman-ABC model. McCarthy Verbal scale was closely associated with the Achievement/Verbal factor; McCarthy Perceptual performance scale loaded highly on the Simultaneous Processing dimension; and McCarthy Quantitative was associated with all three factors. These results provide useful guidelines for interpreting a child's performance on each Index of the McCarthy scales in terms of the mental processing approach used to solve the task. However, the psychometric results must be coordinated with the examiner's clinical observations of the child's problem-solving strategies during administration of the McCarthy scales to understand more completely the processing demands of the Verbal, Perceptual performance, and Quantitative Scales.