Learners’ Proficiency Level and the Efficacy of Written Corrective Feedback on L2 Acquisition

This study aimed to investigate whether an individual learner difference factor of proficiency level mediates the efficacy of written corrective feedback (CF) on L2 acquisition. In a quasi-experiment conducted to attain this end, three types of written CF (i.e., indirect CF, direct CF, and metalinguistic CF) were considered, and English article errors were targeted for the written CF. EFL college students were formed into eight groups distinguished by proficiency level (i.e., higher and lower) and the type of CF to receive. They carried out three narrative writing tasks for written CF treatments and went through pretest, immediate and delayed posttest sessions. At each session, two subtests were administered to measure explicit and implicit knowledge, respectively. The results revealed that the efficacy of CF was mediated by learners’ proficiency level. However, the mediating effect was limited: proficiency level mediated the efficacy of indirect CF, but had no impact on that of direct CF and metalinguistic CF. In addition, the mediating effect emerged only for explicit knowledge, not for implicit knowledge. The results indicate that the proficiency level of learners constitutes a significant factor to be considered for the effective practice of written CF.