Matthew effect in vocabulary and reading: A comparison of good and average readers in Grade 1 to Grade 3

There is quite a large body of research about the influence that vocabulary plays in poor comprehenders reading. Yet, little is known about the role of vocabulary in good comprehenders' reading skills. In the present study, third graders with a one-year advantage in reading comprehension (N = 105) were compared to average comprehenders (N = 177) in terms of vocabulary knowledge at three timepoints (Grade 1 to 3). Vocabulary was operationalized as vocabulary breadth (receptive and expressive) and vocabulary depth in form of semantic word knowledge. Latent growth models showed a superiority of good over average comprehenders both crosssectionally and longitudinally in all assessed vocabulary skills. Moreover, the impact of vocabulary skills on sentence and text reading increased significantly from Grade 1 to Grade 3 in both groups. These results substantiate the increasing importance of vocabulary skills on reading comprehension yielding a Matthew effect.