Measuring productive vocabulary of toddlers in low-income families: concurrent and predictive validity of three sources of data

This study examined parental report as a source of information about toddlers' productive vocabulary in 105 low-income families living in either urban or rural communities. Parental report using the MacArthur Communicative Development Inventory-Short Form (CDI) at child age 2;0 was compared to concurrent spontaneous speech measures and standardized language assessments, and the utility of each source of data for predicting receptive vocabulary at age 3;0 (Peabody Picture Vocabulary Test) was evaluated. Relations between language measures of interest and background variables such as maternal age, education, and race/ethnicity Were also considered. Results showed that for the sample as a whole, parental report was moderately associated with other language measures at age 2; 0 and accounted for unique variance in PPVT at age 3;0, controlling for child language skills derived from a standard, cognitive assessment. However, predictive validity differed by community, being stronger in the rural than in the urban- community. Implications of significant differences in back-ground characteristics of mothers in the two sites are discussed.