Providing feedback on academic writing can serve a valuable purpose for promoting writing ability. Despite the large number of studies in this regard, there is no consensus among the scholars on the benefits of feedback in Foreign Language Learning (FLL) in general and in Second Language Writing (L2W) in particular. The majority of studies have not examined the long-term effects on the learners’ writing. Therefore, there is a need for more well-designed studies to reach a firm conclusion (Guenette, 2007; Sheen, 2007; Ferris, 2004). Using a pretest-posttest design, the present study examined the effects of two types of written corrective feedback, indirect and dynamic, on Iranian EFL learners’ academic writing over time. For this purpose, 56 EFL learners were assigned to two experimental groups and one control group. The treatment effects were tested using 6 in- class writing task along with 3 writing tests. And the data were finally analyzed and compared through t-test and ANOVA. The results revealed that the experimental groups outperformed the control group on the delayed posttest. Furthermore, dynamic feedback was more, though not statistically significant, effective on the immediate posttest while indirect feedback produced better effects, though not statistically significant, on the delayed posttest. The findings carry important instructional implications and applications for the language classroom.
