Study 1 – Longitudinal Study
Initial investigations of data gathered from the LARRC longitudinal study explored the dimensionality of language ability in young children for both English speaking and DLL students. Findings demonstrated emergent dimensionality of language across development with distinct factors of vocabulary, grammar, and higher-level language skills, confirming that higher-level language skills are an important source of variance in children’s language ability. Data also allowed for an investigation of factors that influence the development of reading comprehension. This investigation suggested that the influence of decoding skill decreased with increasing grade and the influence of listening comprehension increased. Further, results indicated that language skills (particularly vocabulary skills) indirectly affected reading comprehension through both decoding skill and listening comprehension.
Subsequent data analyses confirmed the importance of higher-level language skills to reading and listening comprehension, thereby extending our preliminary findings. In analyses of concurrent data, we have found that the dimensions of oral language skills identified in our earlier work (vocabulary, grammar, higher-level language skills) each explain unique variance in concurrent reading comprehension (in Grade 3), most critically at the lower end of the reading comprehension skill distribution. Longitudinally, our data show that oral comprehension monitoring in Grade 1 predicts reading comprehension in Grade 3, over and above word decoding and vocabulary skills. In addition, preschoolers show distinct profiles of lexical quality that predict their literacy outcomes in first grade.
Our examination of the role of memory/attention resources to the prediction of listening and reading comprehension (concurrent and longitudinal) has revealed a complex relationship. Memory and attention are more important in the concurrent prediction of listening than of reading comprehension, and this contribution made by these cognitive resources increases between Grades 1 to 3. However, memory is not found to be a unique predictor of reading comprehension once variation in both lower- and higher-level language skills is taken into account. This may be because complex language skills draw heavily on working memory resources, a finding that warrants further investigation.
Implications: Findings relevant to dimensions of language suggest that higher-level language skills represent an important additional dimension to be accounted for in studying growth in language skills over the course of childhood. Results regarding reading comprehension development, which provide a comprehensive view of critical influences on reading in the early grades to include language factors, have diagnostic and instructional ramifications for improving reading pedagogy. Our work on the differential prediction of memory and attention to reading and listening comprehension has implications for classroom practice.
Study 3 – Randomized Controlled Trial
We have analyzed data from curriculum-based measures to examine the impacts of the two instantiations of Let’s Know! on students’ comprehension-related skills (comprehension monitoring, understanding narrative and expository text as supported by inference making and knowledge of text structure, and vocabulary) as proximal measures of efficacy. Results from the first cohort of the field-based randomized controlled trial (N = 766 students across grades) indicate large, consistent, and statistically significant effects on curriculum-based comprehension monitoring and vocabulary probes relative to control, minimal effects on understanding narrative and expository text probes relative to control, and few differences across the two instantiations.