This study delves into the intricate landscape of second language (SL) writing assessment, with a focus on rater-associated variables and the impact of Dynamic Assessment (DA) on learners’ writing achievement. DA is an approach that combines instruction and assessment to mediate with the areas that students need help with to promote learners understanding and writing skills. To conduct this study, 90 participants were first given an online Oxford placement test and then, they were asked to write a descriptive essay as a pre-test, according to which, the students were randomly assigned to interventionist, interactionist, and control groups. Subsequently, the two experimental groups attended five weekly sessions in which the instructor introduced the five components of descriptive writing. The students were then given a writing task as the post-test and were asked to fill out a Five Factor Personality Inventory. The analysis of the data obtained reveals that students’ personality traits significantly affect their performance in descriptive writing. Also, both interactionist and interventionist techniques exhibit a positive influence on learners' writing achievement. Furthermore, the study compares the impact of interaction and intervention techniques, concluding that both are effective in enhancing EFL learners' writing achievement. This resonates with the broader academic discourse where dynamic assessment is recognized as a central goal of language learning, and autonomy is considered an indispensable prerequisite for successful language acquisition. The study's results are supported by parallel research reinforcing the positive influence of interactionist and interventionist approaches on learners' writing skills. پرونده مقاله