Abstract

In Indonesia, the implementation of STEM (Science, Technology, Engineering, and Mathematics) education faces various challenges. One is the perception that STEM education is difficult, targeting only individuals with high intellectual abilities. This study aims to validate an instrument designed to measure students’ self-efficacy, self-concept, and interest in mathematics activities within STEM education, using the Rasch Model. A quantitative approach was employed, with the Rasch Model applied to test the validity and reliability of the instrument. The instrument consisted of three main components: self-efficacy, self-concept, and students’ interest in STEM-based mathematics activities, measured through a questionnaire distributed to high school students in Greater Jakarta, including Bogor, Depok, Tangerang, and Bekasi City area. The results showed that the developed instrument had strong measurement quality, with adequate validity and reliability levels. All indicators in the instrument were shown to be consistently and accurately measured, and were relevant to the context of mathematics learning in STEM. This study concludes that the validated instrument effectively measures the psychological factors influencing students’ interest and success in STEM education, providing a solid foundation for developing more effective STEM curricula in the future.