Assessment of students' science literacy skills using diagnostic items on the concept of energy with Rasch modeling

This study aims to describe the quality of diagnostic items of the concept of Energy developed based on Rasch modeling and describe students' science literacy skills on the concept of Energy. The research method used in this research is descriptive. Research data were collected through online and offline tests and analyzed using the Rasch model and diagnostic items. The results showed that (1) The science literacy test instrument made was valid with an excellent category and a reliability value of 0.97, meaning that the quality of the items in the instrument was very good. This instrument can be used to assess students' abilities at all levels of ability, from those with low to high abilities; (2) For Person reliability or the quality of students' answers, the reliability value is below 0.30, meaning that the consistency of answers from students is low; (3) The quality of item questions based on the Rasch model from the item measure statistics results that all items meet the MNSA outfit criteria and no negative PTMEA Corr occurs. That is, all items are non-deviant, appropriate, and valid. This is also confirmed based on the bubble chat, where there are no items that are overfit or underfit; (4) The Rasch model makes very thorough and good measurements to measure the difficulty level of items and person's ability; (5) Based on the measurement results, it was found that the science literacy ability of students at SMPN 1 Paleleh was divided into low ability as much as 1.6%, moderate 53.6%, high 43.8%, very high 0.82%.