Construct the Validity of STEM and Project-based Critical Thinking Skills Test Instruments Using the Rasch Model

Abstract

Abstract. Students' critical thinking skills are very important abilities in the 21st century. To measure critical thinking skills, a valid and reliable instrument is needed. This article uses the Rasch model to construct an instrument for critical thinking skills on number pattern material whose learning uses STEM PjBL. The development method uses the analysis, design, development, implementation, and evaluation (ADDIE) stages. Data processing uses the Rasch model assisted by the Winstep program. The instrument was tested on 33 public junior high school students in Semarang. The research results include validity, namely the validity test by experts with an average percentage of 92.4% in the very valid category, the quality of the questions in the instrument reliability aspect is good, and the average critical thinking ability of students who use STEM-based and Project Based instruments Learning was 61.46, higher than other classes at 49.79. The critical thinking test instrument is based on STEM and the project needs to be further developed on other materials.