Analytic Approach of Response Pattern of Diagnostic Test Items in Evaluating Students’ Conceptual Understanding of Characteristics of Particle of Matter

This research aimed to evaluate the students’ conceptual understanding and to diagnose the students’ preconceptions in elaborating the particle characteristics of matter by development of diagnostic instrument as well as Rasch model response pattern analysis approach. Data were acquired by 25 multiple-choice written test items distributed to 987 students in North Sulawesi, Indonesia. Analysis on diagnostic test items response pattern was conducted in three steps: 1) conversion of raw score to a homogenous interval unit and effectiveness analysis of measurement instruments; 2) measurement of disparity of students’ conceptual understanding; and 3) diagnosis of students’ preconception by estimation of item response pattern. The result generated information on the diagnostic and summative measurement on students’ conceptual understanding in elaborating the topic; information also acts as empirical evidence on the measurement’s reliability and validity. Moreover, the result discovered a significant disparity between students’ conceptual understanding based on their educational level. It was found that the distractor item response pattern tended to be consistent, indicating a certain tendency of resistant preconception pattern. The findings are expected to be a recommendation for future researchers and educational practitioners that integrate diagnostic and summative measurement with Rasch model in evaluating conceptual understanding and diagnosing misconception. Keywords: conceptual understanding, item response, particle of matter, Rasch model