Measurement properties of the MacArthur Communicative Development Inventories at ages one and two years

In a prospective study of child development in relation to early-life otiti s media, we administered the MacArthur Communicative Development Inventorie s (CDI) to a large (N = 2,156), sociodemographically diverse sample of 1- a nd 2-year-old children. As a prerequisite for interpreting the CDI scores, we studied selected measurement properties of the inventories. Scores on th e CDI/Words and Gestures (CDI-WG), designed for children 8 to 16 months old , and on the CDI/Words and Sentences (CDI-WS), designed for children 16 to 30 months old, increased significantly with months of age. On several scale s of both CDI-WG and CDI-WS, standard deviations approximated or exceeded m ean values, reflecting wide variability in results. Statistically significa nt differences in mean scores were found according to race, maternal educat ion, and health insurance status as an indirect measure of income, but the directionality of differences was not consistent, across inventories or acr oss scales of the CDI-WS. Correlations between CDI-WG and CDI-WS ranged fro m .18 to .39. Our findings suggest that the CDI reflects the progress of la nguage development within the age range 10 to 27 months. However, researche rs and clinicians should exercise caution in using results of the CDI to id entify individual children at risk for language deficits, to compare groups of children with different sociodemographic profiles, or to evaluate the e ffects of interventions.