Developmental classification of reading-disabled children

The present study developed and used longitudinal cluster analysis, a multivariate classification technique, to classify a sample of 200 nonclinical normal and reading-disabled males based on their performances on a neuropsychological battery at kindergarten, second, and fifth grades. The resulting classification was examined against various internal and external validation criteria. Using a validation framework, five developmental subtypes of children, two normal and three deficit reader groups, were found. Three of these groups could best be described as partitions of a multivariate normal distribution; the other two, both containing deficit readers, showed different covariance structures, suggesting differing developmental patterns. These groups were shown to differ with respect to the domains of academic achievement, parental achievement, neurological status, birth histories, school behaviors, and neuropsychological-cognitive development. The results suggest that developmental classifications can be formed by using multivariate classification methods and the subtypes support findings from cross-sectional classification research on similar populations.