Effects of Oral Corrective Feedback on Grammatical Accuracy in L2 Speaking: A Three-Level Meta-Analysis

Oral corrective feedback (OCF) has been frequently used to address spoken errors, yet the extent to which it improves second language (L2) speaking accuracy remains inconclusive. Previous meta-analyses have blended oral and written measures and are thus unable to answer this question. To narrow this gap, we examined the effects of OCF on grammatical accuracy in L2 speaking through a three-level meta-analysis of 55 primary studies (292 effect sizes, N = 3,352). The results revealed a medium-to-large overall effect ( g = 0.92, 95% CI [0.69, 1.15], p < .001). Moderator analyses provided quantitative evidence for the potential benefits of encouraging learner self-repair and using multiple feedback moves. Notably, the effect of OCF declined significantly over time, a pattern that contrasts with previous meta-analytic reviews. In addition, oral production tasks yielded significantly larger effects than elicited imitation, suggesting that effect sizes vary with testing instruments even within the same modality. These findings were discussed in light of the Noticing Hypothesis, the Skill Acquisition Theory, and the Transfer-Appropriate Processing Hypothesis. The study concludes with pedagogical and methodological recommendations, enriching our understanding of OCF treatment in L2 speaking instruction.