Beyond breadth: The contributions of vocabulary depth to reading comprehension among skilled readers.

This study investigated the relationships among vocabulary breadth, vocabulary depth, reading comprehension, and reading rate among college-aged students. While the relationships of some of these variables have been explored in previous research, the current study's focus on the role of vocabulary depth on the literacy measures within a sample of skilled readers is new and produced several interesting findings. First, consistent with the hypotheses, both vocabulary breadth and depth were significantly correlated with reading comprehension and reading rate. Second, while both types of vocabulary knowledge explained unique variance in reading comprehension, only vocabulary breadth explained unique variance in reading rate. Finally, although vocabulary breadth was significantly correlated with both of the vocabulary depth measures, the two depth measures were not significantly correlated with each other. This work implies that a strong depth of vocabulary affects reading comprehension, in addition to the well-established relationship between vocabulary breadth and comprehension.