علیرضا محمدبیگی

The present mixed-method study sought to investigate the efficacy of using an interventionist dynamic assessment and specifically its formats namely the cake and the sandwich ones on learners’ grammatical English Tenses. In doing so, 45 advanced learners of English language at Iran Language Institute (ILI) in Shiraz, Iran were selected. They were randomly assigned to 3 groups, each including 15 participants. Two experimental groups namely the cake and the sandwich ones received the interventionist dynamic assessment test while the third group received a non-dynamic grammar test which was functioning as a control group. As the study utilized a sequential exploratory design (QUAN → qual) of mixed method approach (MMR), the quantitative part was carried out via a well-established grammar test and in the qualitative component, six informants (3 from the cake group and 3 from the sandwich group) were selected to be interviewed and their quotations were descriptively analyzed through a sociocultural perspective. The quantitative component of the study revealed the outperformance of the two experimental group over the control group. However, the two modes of delivering mediation in experimental groups had no statistically significant difference on the degree of the acquisition of grammatical English tenses by learners. The interview analysis of the negotiations also demonstrated positive viewpoints of learners about the two experimental groups. Merging the quantitative and qualitative analyses, the study found that interventionist dynamic assessment, in both modes, could have positive effects on learners’ ability to improve their acquisition of English tenses.