The Big Picture: A Meta-Analysis of Program Effectiveness Research on English Language Learners
This article presents a meta-analysis of program effectiveness research on English language learners. The study includes a corpus of 17 studies conducted since Willig's earlier meta-analysis and uses Glass, McGaw, and Smith's strategy of including as many studies as possible in the analysis rather than excluding some on the basis of a priori “study quality” criteria. It is shown that bilingual education is consistently superior to all-English approaches, and that developmental bilingual education programs are superior to transitional bilingual education programs. The meta-analysis of studies controlling for English-language-learner status indicates a positive effect for bilingual education of .23 standard deviations, with outcome measures in the native language showing a positive effect of .86 standard deviations. It is concluded that bilingual education programs are effective in promoting academic achievement, and that sound educational policy should permit and even encourage the development and implementation of bilingual education programs.