Does "more complexity" equal "better writing"? Investigating the relationship between form-based complexity and meaning-based complexity in high school EFL learners' argumentative writing

The study examines the relationship between form-based complexity and meaning-based complexity in argumentative essays written by high school students learning English as a foreign language (EFL) in relation to writing quality. The data comprise argumentative essays written by 102 Japanese high school learners at different proficiency levels. The students' proficiency levels were determined based on the evaluation of their argumentative essays by human raters using the GTEC rubric. The students' essays were analyzed from multiple dimensions, focusing on both form-based complexity (lexical complexity, large-grained syntactic complexity, and fine-grained syntactic complexity features) and meaning-based complexity (argument quality). The results of the multidimensional analysis revealed that the most influential factor in determining overall essay scores was not form-based complexity but meaning-based complexity achieved through argument quality. Moreover, the results indicated that meaning-based complexity was strongly correlated with the use of complex nominals rather than clausal complexity. These insights have significant implications for both the teaching and assessment of argumentative essays among high school EFL learners, underscoring the importance of understanding what aspects of writing to prioritize and how best to assess student writing.