Objective: Until recently, normative data on language and communication development among children in the United States have not been available to inform critical efforts to promote language development and prevent impairments. This study represents the first psychometric assessment of nationally representative data derived from a National Survey of Children's Health (NSCH) pilot measure of language and communication development among children ages 1 to 5 years.
Methods: We analyzed 14,573 parent responses to language and communication items on the 2018 and 2019 NSCH to evaluate whether the newly added 11 items represent a single latent trait for language and communication development and to determine normative age of success on each item. We applied weighted, one-parameter Item Response Theory to rate and cluster items by difficulty relative to developmental language ability. We examined differential item functioning (DIF) using weighted logistic regression by demographic factors.
Results: Together, exploratory factor analysis resulting in a single factor > 1 and explaining 93% of the variance and positive correlations indicated unidimensionality of the measure. Item characteristic curves indicated groupings were overall concordant with proposed milestone ages and representative of an approximate 90% success cut-point by child age. Indicated normative age cut-points for 3 of the items differed slightly from proposed milestone ages. Uniform DIF was not observed and potential nonuniform DIF was observed across 5 items.
Conclusions: Results have the potential to enhance understanding of risk and protective factors, inform efforts to promote language and communication development, and guide programmatic efforts on early detection of language delays.
Keywords: Item Response Theory; language development; language milestones; psychometrics; survey data.
Published by Elsevier Inc.