Erna Noor Savitri, Sudarmin, Murbangun Nuswowati, Sigit Saptono, Ani Rusilowati, Endang Susilaningsih, Roswanna Safkolam
This research aims to develop a digital literacy instrument and test it on prospective science teachers using the Rasch Rating Scale Model. The study involved 81 second-semester students from the Science Education Study Program at Semarang State University (UNNES) and 59 students from UIN Salatiga. The instrument consists of 30 items, 10 essay questions, and 20 questionnaire statements measured using a four-point scale. Data were analyzed using the WINSTEPS Version 5.7.3.0 application. Content validity results show that all essay questions are valid, while 4 out of 20 questionnaire items are inconsistent and require revision. Construct validity analysis indicates that the essay questions account for 29% of the total variance, and the questionnaire explains 46%. The internal consistency (KR-20) is acceptable for essay questions (0.65) and very high for the questionnaire (0.83). Item reliability is excellent, with 0.92 for essay questions and 0.98 for the questionnaire. Item characteristics show a standard deviation of 0.35 for essay questions and 1.01 for the questionnaire. Reliability was evaluated using KR-20 for essay-based items and Cronbach’s Alpha for the questionnaire. This ensures consistency in reporting reliability across both test and non-test components. Differential Item Functioning (DIF) analysis reveals bias in several essay questions between groups, with low probability values and high DIF contrast. In contrast, the questionnaire items function similarly across both groups. Biased items were reviewed and revised. Overall, the instrument demonstrates strong reliability and is suitable for measuring digital literacy in prospective science teachers. © 2026 Savitri et al. Published by Pejabat Karang Mengarang (UPSI Press).
Faculty of Mathematics and Natural Sciences, Universitas Negeri Semarang, Semarang, 50229, Indonesia; General Science Program, Faculty of Science Technology and Agriculture, Yala Rajabhat University, Yala Province, Yala, 95000, Thailand
