The dimensionality of phonological awareness: An application of item response theory

A battery of 7 tasks composed of 105 items thought to measure phonological awareness skills was administered to 945 children in kindergarten through 2nd grade. Results from confirmatory factor analysis at the task level and modified parallel analysis at the item level indicated that performance on these tasks was well represented by a single latent dimension. A 2-parameter logistic item response (IRT) model was also fit to the performance on the 105 items. Information obtained from the IRT model demonstrated that the tasks varied in the information they provided about a child's phonological awareness skills. These results showed that phonological awareness, as measured by these tasks, appears to be well represented as a unidimensional construct, but the tasks best suited to measure phonological awareness vary across development.