The Reading Comprehension and Vocabulary Knowledge of Children with Poor Reading Comprehension despite Adequate Decoding: Evidence from a Regression-Based Matching Approach.

The present study examined the reading comprehension and receptive vocabulary skills of children with poor reading comprehension despite adequate decoding using a regression-based matching technique. Participants included five cohorts of children who were identified as typical readers (N = 70,493 - 75,553) or as children with specific reading comprehension difficulties (N = 480 - 8,717). Across cohorts, children with specific reading comprehension difficulties exhibited oral language difficulties based on a measure of vocabulary; however, the observed weakness in vocabulary was not as severe as their reading comprehension difficulties. Results from the regression-based matching technique suggested that the vocabulary weakness for these children is better characterized as a developmental delay rather than a developmental deficit. This outcome also emerged when more stringent criteria were used to identify subgroups of readers. Although children with poor reading comprehension despite adequate decoding have a weakness in at least one aspect of oral language, their oral language weakness does not account for the severity of their reading comprehension difficulties. Theoretical and practical implications are discussed.