The Impact of Vocabulary Instruction on Passage-Level Comprehension of School-Age Children: A Meta-Analysis

TLDR

The authors conducted a meta‑analysis of 37 vocabulary‑instruction studies across pre‑K to 12th grade to clarify its effect on passage‑level comprehension. They aggregated data from these studies to evaluate how vocabulary interventions influence comprehension outcomes. The analysis revealed that vocabulary instruction improved comprehension on custom measures (d = 0.50) but had a smaller effect on standardized tests (d = 0.10); students with reading difficulties benefited more (d = 1.23) than those without (d = 0.39), while vocabulary gains were similar across ability levels, and the correlation between vocabulary and comprehension effects was modest (r = 0.43).

Abstract

A meta-analysis of vocabulary interventions in grades pre-K to 12 was conducted with 37 studies to better understand the impact of vocabulary on comprehension. Vocabulary instruction was found to be effective at increasing students' ability to comprehend text with custom measures (d = 0.50), but was less effective for standardized measures (d = 0.10). When considering only custom measures, and controlling for method variables, students with reading difficulties (d = 1.23) benefited more than three times as much as students without reading problems (d = 0.39) on comprehension measures. Gains on vocabulary measures, however, were comparable across reading ability. In addition, the correlation of vocabulary and comprehension effects from studies reporting both outcomes was modest (r = .43).