Factor structure of the WISC-R and ITPA for learning-disabled, emotionally disturbed, and control children

There has been considerable interest in determining possible learning differences in specific populations of children. Stewart (1977) factor analyzed the WISC and ITPA for learning-disabled and mentally retarded samples and compared the results to a control group. He concluded that while the factors were quite similar, evidence suggested different learning processes in the groups studied. The present study (N = 301) enlarged and modified Stewart's study; it replaced the WISC with the WISC-R and the mentally retarded group with an emotionally disturbed sample. Three factors that emerged for all groups (linguistic, memory, and visual-motor) were similar to Stewart's findings. Additional factors highlighted motor skills and a separation in auditory and visual tasks for the learning-disabled group, an expressive factor for the emotionally disturbed, and a conceptual factor for the emotionally disturbed and control groups that was not found for the learning-disabled sample. Results suggested the need for individualized instruction.