Characteristics of Assessment Instrument for Diagram and Verbal Representation Ability of High School Physics Students in Physics with Partial Credit Model

摘要

The characteristics of assessment instrument are important to obtain representative information about students' knowledge and abilities in education. The representation ability is fundamental ability to solve problems in learning Physics. This study aims to determine the characteristics of assessment instrument for the representation abilities of diagram and verbal in high school Physics. The assessment instrument consists of two test sets with four category response according to Partial Credit Model (PCM). The subject of the research was a sample of 305 students of XI IPA class from high schools in Yogyakarta. The subject was selected through purposive sampling based on the result of national high school examination year 2016/2017. The research data were analyzed with item response theory (IRT) according to PCM. Based on the result estimation of parameter and student ability, that (1) item difficulty index ranged from -1.02 to +1.17, which satisfies the criteria of good test items; (2) all test items fit with the PCM model; (3) the information function is 10 and SEM is 0.21; and (4) the ability estimation ranges from -2.08 to +2.10, indicating that students' abilities are varied. The assessment instrument fits with PCM model and can be categorized as good, meaning that it can be used to measure diagram and verbal representation abilities of high school students in Physics.