Testing predictive validity of the Communication Composite of the Communication and Symbolic Behavior Scales

This study tested the predictive validity of the Communication Composite of the Communication and Symbolic Behavior Scales as a predictor of expressiv e vocabulary. The Communication Composite consists of six clusters that mea sure specific aspects of communicative behavior. Participants were 58 child ren, 17 to 34 months of age, who were functioning at the prelinguistic stag e of language development. All children had mild to moderate developmental delays but no sensory impairments. The Communication Composite was used to measure prelinguistic communication skills at the beginning of the study, a nd an unstructured play session was used to measure expressive vocabulary 1 year later. Results indicated that the Communication Composite was a signi ficant predictor of later expressive language. In addition, all tested clus ters were significant predictors of later expressive language.