The Immediate and Delayed Effects of Interactionist vs. Interventionist Dynamic Assessment (DA) on EFL Learners’ Speaking Complexity, Accuracy, and Fluency (CAF)

Dynamic Assessment (DA) has increasingly been recognized as a promising approach for integrating assessment and instruction in second language learning. Despite their growing application, limited research has systematically compared the two major DA paradigms (i.e., interactionist and interventionist), particularly regarding their short- and long-term effects on learners’ speaking performance. The present study aims to address this gap by investigating the immediate and delayed impacts of interactionist and interventionist DA on English as a foreign language (EFL) learners’ speaking complexity, accuracy, and fluency (CAF). Eighty-six advanced EFL learners from a language center in Tehran, Iran were assigned to three groups based on the Oxford Placement Test. Following a speaking pretest, learners in the experimental groups received eight sessions of either interactionist or interventionist DA, while the control group underwent regular speaking assessment. An immediate and a delayed speaking post-test were used to evaluate both short-term progress and retention. Two trained raters scored the CAF measures, and the data were analyzed using repeated-measures two-way ANOVA and MANOVA. The findings indicated no significant differences between the two DA approaches; however, both experimental groups significantly outperformed the control group on the immediate and delayed post-tests. These results suggest that regardless of the mediation type, DA effectively enhances learners’ speaking performance and promotes the durability of learning gains. The study highlights the pedagogical value of embedding DA-based mediation into routine speaking assessment, enabling teachers to provide targeted scaffolding that supports both immediate improvement and longer-term development in learners’ oral proficiency.