Applying the Rasch model to measure students’ critical thinking skills on the science topic of the human circulatory system

Critical thinking (CT) is essential in science education to enable students to deeply understand scientific concepts and apply their knowledge to solve complex real-world problems. Despite its importance, a notable gap remains in the availability of instruments designed to measure CT in specific science topics. This study addresses this gap by testing the accuracy of an instrument for assessing secondary students’ CT related to the human circulatory system, focusing on six APA-defined indicators: interpretation, analysis, inference, evaluation, explanation, and self-regulation. The study was conducted in Bantul Regency, Yogyakarta, Indonesia, and involved 445 8th-grade students from urban, middle, and rural schools. Data were collected through an online test administered in collaboration with teachers after students had completed the topic. Using the Rasch model for data analysis improved the accuracy and consistency of the instrument. Results showed that self-regulation was CT subskill with the lowest mean score, highlighting it as a priority for development. At the same time, interpretation had the highest mean score, particularly in the level 4 rating category, making it the most mastered skill. These findings underscore the need for educators to develop targeted learning strategies that enhance CT skills and adapt them to other science topics with similar complexity to the human circulatory system.