摘要：The present study investigated the effects of applying cumulative group dynamic assessment (G-DA) procedures (Poehner, 2009) to support EFL writing development in a university context in Iran. It focused on learner achievement, patterns of occurrence of mediation incidents, and learners’ and teachers’ perceptions towards G-DA. Quantitative data was collected from learners’ performance on writing tests and the frequency of occurrence of mediation incidents involving EFL writing components based on Jacobs, Zinkgraf, Wormouth, Hartfield, and Hughey’s (1981) scale. Findings revealed that G-DA was more effective than conventional explicit intervention for supporting EFL writing development. Also, it worked best for low ability learners as compared to mid and high ability ones. Besides, the number of mediation incidents declined from 27 in session one to 8 in the final session, confirming the efficacy of G-DA in promoting both EFL writing and learner self-regulation. Most teacher mediation involved language use, vocabulary, and organization and fewer incidents involved content and mechanics. Qualitative data analysis indicated that most learners and teachers held positive attitudes towards the efficacy of G-DA for supporting EFL writing development. However, a few participants asserted that the procedures were unsystematic, stressful, time consuming, and inappropriate for large classes.
