Applying a polytomous Rasch model to investigate Likert scale functioning and L2 writing strategy use

While Rasch models have been increasingly employed in applied linguistics research, their use remains underexplored in L2 writing strategy research, which has relied primarily on statistical methods that assume continuous data. This study aimed to address this methodological gap by applying a polytomous Rasch modelling approach to investigate Likert scale functioning in the context of L2 writing strategy use. Participants were 172 Thai EFL English-major undergraduates who completed a 26-item, 5-category Likert-type scale designed to measure five strategy domains: metacognitive, effort-regulation, cognitive, social, and affective strategies. The data were analysed using a Rasch rating scale model (RSM) implemented in Winsteps and Facets software programmes. The main results indicated that the RSM analysis provided sound evidence of appropriate item and category functioning, while revealing specific areas for refinement, such as limited item coverage, item redundancy, and category disordering. The RSM analysis also revealed systematic trends in Thai EFL students’ writing strategy use across domains and proficiency levels: metacognitive strategies were used most often and clearly differentiated higher- and lower-achieving students, while social strategies were less common and more frequently used by lower achievers. These findings highlight the value of a polytomous Rasch modelling approach in examining not only rating scale functioning but also writing strategy use. The present findings have implications for rating scale validation and L2 writing strategy instruction.