Validity of the Communication Function Classification System for use with preschool children with communication disorders

Aim: To evaluate construct validity of the Communication Function Classification System (CFCS) for use with preschoolers with a range of speech and language disorders. Method: Seventy-seven preschoolers with speech and language disorders (M = 2.7 years, SD = 1.02 years) (50 males) participated in this cohort study. Preschoolers had speech and language, language-only, or speech-only disorders. Together with parent input, SLPs completed the CFCS at Time 1. Parents and SLPs then independently completed a validated change-detecting functional communication outcome measure, the Focus on Communication Outcomes Under Six (FOCUS©) three times – at assessment (Time 1), at the start of treatment (Time 2), and at the end of treatment (Time 3). Results: There was a significant negative correlation between CFCS classifications and FOCUS© scores at all three measurement points for the ratings by both parents and SLPs (correlations ranged from -.60 to -.76). As expected, no correlations between CFCS classifications and FOCUS© change scores were statistically significant. Interpretation: This study provides evidence of construct and predictive validity of the CFCS, demonstrating its value as a discriminative tool for use with preschoolers with a range of speech and language disorders