A Probe into Iranian Learners’ Performance on IELTS Academic Writing Task 2: Operationalizing Two Models of Dynamic Assessment versus Static Assessment

Abstract Dynamic Assessment (DA) has been utilized for language evaluation. This mixed-methods study aimed to examine the potential impact of interactionist and interventionist models, as two significant offshoots of dynamic assessment on IELTS candidates’ performance in academic writing task 2. The study also compared the efficiency of these dynamic models and static assessment in the overall writing development of potential IELTS test-takers’ proficiency in writing task 2 in terms of IELTS writing assessment criteria. An experimental pretest-treatment-posttest design was employed. A qualitative approach was also conducted using field notes as a cross-validation strategy. To this end, 54 (26 males and 28 females) Iranian IELTS candidates aged 19 to 35 were randomly assigned to one control and two experimental groups (n=18). Initially, a pre-test was run to assess all participants’ developing writing skills. Afterward, the experimental groups received treatments based on interactionist and interventionist models, whereas the control group received no dynamic treatment in the form of interactionist and interventionist models and was trained according to the conventional static methods of writing instruction. Finally, a post-test was administered to check the treatments’ efficacy. The quantitative results demonstrated that the interventionist group’s writing performance was significantly better than that of the static group. However, there existed no statistically significant difference between the DA groups’ writing performance. The qualitative findings substantiated the quantitative results indicating the outperformance of dynamic assessment over the static assessment approach in the development of IELTS writing task 2 skills. The research findings have some pedagogical implications for IELTS teachers.