Design of Rasch-Based Evaluation Scale for Chemistry Experimental Teaching Literacy among Pre-Service Teachers

Experimental teaching competence constitutes a fundamental component of professional literacy for pre-service chemistry teachers, reflecting their ability to integrate theoretical knowledge with practical laboratory skills, organize and present experimental procedures effectively, and adapt their instructional strategies to diverse learning situations. Systematically assessing the developmental level of this competence is critical for guiding teacher preparation programs, informing curriculum design, and promoting the overall quality of chemistry education. Based on the Rasch measurement model, this study developed a comprehensive evaluation scale tailored to pre-service chemistry teachers' experimental teaching literacy. By deconstructing the workflow of experimental teaching tasks, a four-dimensional framework was established, encompassing "knowledge understanding, skill execution, expression and organization, and thinking adjustment," with twelve initial indicators. These indicators were translated into 75 test items through a rigorous development process involving iterative expert review and multiple revisions. The scale was administered to 244 pre-service chemistry teachers from two universities, and Rasch modeling analysis was performed using Winsteps software. Items were evaluated and refined based on fit statistics, discrimination indices, and other relevant metrics, resulting in a final scale containing 56 well-functioning items. Empirical analysis indicates that the finalized scale demonstrates strong internal consistency, robust construct validity, and the capacity to provide multidimensional and precise assessment of experimental teaching literacy. By offering a reliable and empirically validated tool, this study supports both research and practical evaluation in chemistry teacher education, enabling educators and program designers to identify strengths and areas for improvement, and to tailor instructional interventions that enhance the development of high-quality experimental teaching competencies among pre-service teachers.