A Rasch Model Analysis on Acid-Base Reading Literacy Instruments

Legian Setyorini, Sri Haryani, Endang Susilaningsih & Sudarmin

Chemistry Education, UNNES Post Graduated, Indonesia

legiansetyorini@students.unn, Haryanikimia83@mail.unnes.ac, endang.arkan@gmail.com & sudarmin@mail.unnes.a


One of the classical analysis areas for improvement is the inability to produce accurate and valuable data in interpreting test score information to measure a student’s ability. If the same score is obtained from a test item with a varying degree of difficulty, it must indicate that the student has varied skills. An analysis of the Rasch model will address this shortcoming. The student’s ability and the connection of students’ skills-difficulty items serve as the foundations for the Rasch model. This quantitative study aimed to analyze the quality of the items by validating the acid-base reading literacy instruments using the Rasch model. The research sample was 88 students of Semarang State University and UIN Kudus. The data collected was from students’ answer data to the 13 items of acid-base reading literacy instruments. Data analysis uses the Rasch model with the PCM model Winstep application. The analysis results show that the quality of the acid-base reading literacy instruments is suitable based on the following aspects: unidimensional, item fit, reliability of item and person, and difficulty item level. The construct validity was excellent criterion, and the first contrast of unexplained variance was in a good category. The item reliability is in excellent criteria, and the person reliability is in fair criteria. Two items need to be revised, namely questions number 5 and 2. The item difficulty level was very easy (31%), easy (38%), difficult (8%), and very difficult (23%).

Keywords: Reading Literacy, Acid-Base, Rasch Model, Winsteps, PCM

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