The motivation for this paper is the authors' recent work on several randomized control trials in which they found the primary result, which averaged across subgroups or sites, to be moderated by demographic or site characteristics. They are led to examine a distinction that the Institute of Education Sciences (IES) makes between "confirmatory"…

Twenty-four studies were included in this systematic review of vocabulary research literature. The review corroborates the findings of past studies that several strategies have emerged that increase students' vocabulary knowledge. Findings further reinforce the National Reading Panel's recommendations regarding the context and magnitude of studies…