The impact of explicit instruction and corrective feedback on ESL postgraduate students’ grammar in academic writing

Abstract

This study investigated the effects of a pilot program of written corrective feedback, supported by explicit grammar instruction, on a range of common errors made in ESL postgraduate writing. It sought to quantify improvement through the reduction of error rates and error categories. This small-scale quasi-experimental study involved 15 ESL doctoral students: 7 in an intervention group and 8 in a semi-equivalent control group. Participants wrote a short essay at the start of the study and a second essay ten weeks later at the conclusion of the study. These essays were analysed for errors, and it was found from linear regression analyses, assuming a constant percentage change in error rate across the groups, that the intervention group produced on average 43% fewer errors at post-test while the control group’s error rate decreased by an average of 12% at post-test. In terms of error categories present in students’ writing, the intervention group had on average 2.4 fewer categories at post-test, while the control group had on average 0.5 more error categories. These results suggest that for ESL doctoral students in the health sciences, substantial gains can be made within a maximum of 16 hours of written language support, while without such support, little if any improvements are likely to occur. Hence, despite the small sample size and the limitations of quasi-experimental designs, this study found evidence that such a program may produce improvement in the accuracy of ESL postgraduates’ grammar, and this encourages further investigation of similar programs.