Differences in Factor Structures of Cognitive Functioning of Learning Disabled (LD) and Emotionally Handicapped (EH) Children

Abstract

Previous empirical studies have been inconsistent in the identification of cognitive differences between learning disabled (LD) and emotionally handicapped (EH) children on psychoeducational assessment batteries. Furthermore, studies using multivariate procedures such as discriminant analysis have failed to verify the basic underlying assumption of homogeneity of variance-covariance matrices of the groups. Homogeneity of covariance can be assessed by comparing factor structures of the groups. This study investigated the cognitive differences between LD and EH children on a psychoeducational assessment battery including the WISC-R, WRAT Arithmetic, and PIAT Reading Recognition, Comprehension, and Mathematics subtests, typically used to identify the two exceptionalities. Differences in factor structures were investigated in an effort to clarify group differences in cognitive functioning and to investigate the utility of multivariate analyses such as discriminant analysis with these two groups of children. The congruence coefficient was used to determine similarities between factors. The Verbal Conceptualization, Perceptual Organization, and Mathematics factors were found to be statistically similar in construct and interpretation. Differences were noted in the factor structures, however, involving the fourth factor, which for the LD group was Reading Achievement and for the EH group was Visual Motor Performance. As the results indicated the presence of heterogeneity in the matrices of LD and EH children, caution was suggested in the interpretation of multivariate statistical analyses with these children. Violation of the assumption of homogeneity can invalidate statistical findings and their application to the study of group differences.