Evidence-Based Practices of English Language Teaching: A Meta-Analysis of Meta-Analyses

This meta-analysis aims at investigating the impact of English language teaching practices on language outcomes. The literature search yielded 90 meta-analyses that were published between January, 1995 and December, 2019. The current study analyzed 90 meta-analysis and these studies comprised 3496 studies, 7870 effect sizes and nearly 700,000 students. Three moderator variables were examined- year of publication, setting and educational level. The results showed that a) language learning strategies had medium impact on language outcomes in general and generated the largest impact on speaking (d=0.90), b) technology-based language learning had medium impact on language outcomes in general and generated the largest impact on vocabulary (d=0.98), c) explicit instruction had medium impact on language outcomes in general and generated the largest impact on grammar (d=1.26), d) mobile-based language learning had small impact on language outcomes in general and generated the largest impact on listening (d=0.73), and e) setting and educational level significantly moderated the impact of teaching practices on language outcomes. The findings were discussed and implication and future research were proposed.