<![CDATA[This study aims to produce mathematics questions that can be used to measure the critical thinking skills of fifth-grade elementary school students on the material of data presentation and interpretation and that meet the criteria of validity and reliability. The method used is Research and Development (R&D) with the Tessmer development model, consisting of preliminary stages, self-evaluation, expert review, one-on-one, small group, and field testing. This study involved 3 students in the one-on-one stage, 6 students in the small group stage, and 30 students in the field testing stage. Data collection was carried out through expert validation sheets, interviews, and tests and was then analyzed using qualitative and quantitative approaches. The results of the study showed that the assessment of the three validators obtained an average percentage of 81.3%, which was included in the valid category. In the one-on-one and small group stages, the questions developed were considered easy for students to understand and had met the aspects of readability and clarity, so they were worthy of being tested in the field testing stage. The results of the validity test showed that 10 questions (83.33%) were declared valid and 2 questions (16.67%) were declared invalid. Meanwhile, the reliability test results obtained a coefficient of 0.967, which is categorized as reliable. Therefore, it can be concluded that the developed mathematics questions have met the validity and reliability criteria, making them suitable for measuring the critical thinking skills of fifth-grade elementary school students.]]>
