Effectiveness of written corrective feedback in developing L2 accuracy: A Bayesian meta-analysis

Corrective feedback on second language (L2) writing has remained one of the most heavily studied areas in applied linguistics, yet clear guidance for practitioners about how to provide it most effectively remains limited. Previous studies have meta-analysed written corrective feedback (WCF) research revealing conflicting findings in how WCF affects development in L2 writers’ accuracy over time. This study provides a needed update in light of a recent increase in (quasi)experimental WCF studies. It features several methodological advances by introducing a Bayesian approach to conducting a meta-analysis, which provides a more valid picture of the generalizable effects. The analysis allows distinction – for the first time at a meta-analytic level – between short-, medium-, and long-term effects of WCF. Results aggregate data from an initial 52 primary studies that utilized control groups revealing robust evidence of the durability of moderate effectiveness of WCF over time and deeper insight into the relative effectiveness of various types of WCF (e.g. direct, indirect, metalinguistic – all yielding similar effect sizes) across research contexts, writing task types, target error types, and instructional characteristics. We conclude with recommendations to help continue methodological advances in this domain.