We investigated whether individual differences in overall receptive vocabulary knowledge measured at the beginning of the year moderated the effects of a kindergarten vocabulary intervention that supplemented classroom vocabulary instruction. We also examined whether moderation would offset the benefits of providing Tier-2 vocabulary intervention…

Vocabulary knowledge at school entry is a robust predictor of later reading achievement. Many children begin formal reading instruction at a significant disadvantage due to low levels of vocabulary. Until recently, relatively few research studies examined the efficacy of vocabulary interventions for children in the early primary grades (e.g.,…