Individual differences in the vocabulary skills of children with poor reading comprehension

As a group, poor comprehenders (children who have poor reading comprehension despite age-appropriate decoding abilities) have often been shown to have vocabulary difficulties. However, vocabulary knowledge is complex and could affect reading comprehension in more than one way. We explored this complexity by assessing the vocabulary and oral language skills of poor comprehenders at the individual level. All poor comprehenders displayed some degree of oral language deficit in the context of intact nonword and irregular word reading skills, but patterns of oral language deficit differed across participants. The majority had weak vocabulary skills which took the form of semantic weaknesses, while a minority had age-appropriate vocabulary skills but poor syntactic or listening comprehension skills. Our results support the Simple View of Reading and demonstrate the importance of considering individual variation when developing theories of, and treatments for, poor reading comprehension.