<![CDATA[21st-century learning requires educators not only to master content knowledge but also to design learning processes that facilitate higher-order thinking skills (HOTS). Conventional assessment methods, particularly those emphasizing multiple-choice questions and factual recall, are considered insufficient for measuring HOTS, highlighting the need for authentic assessment instruments aligned with project- and problem-based learning. This research and development (R&D) study aims to develop and validate an authentic HOTS assessment instrument based on the C4–C6 cognitive levels of Anderson & Krathwohl's taxonomy, integrated with the Hybrid ProBL (Project–Problem Based Learning) model using a design thinking approach, and to describe the results of its initial trial. Instrument development followed the 4-D model (Define, Design, Develop, and Disseminate), encompassing needs analysis, instrument design, expert validation, and limited field testing. The instrument was validated by three experts specializing in HOTS content, instructional design, and educational evaluation. A limited trial involving university students was conducted to evaluate the instrument's reliability and practicality. The results indicated that the instrument achieved an average content validity coefficient (Aiken's V) of 0.86, meeting the established content validity criterion, and a Cronbach's Alpha coefficient of 0.89, indicating high internal consistency. The developed instrument shows potential for assessing students' HOTS achievement in contextualized learning activities through project- and problem-based learning. However, this study did not statistically examine the instrument's effectiveness in improving students' HOTS. This study contributes an authentic HOTS assessment instrument that can serve as a reference for teacher education institutions in integrating innovative learning models and authentic assessment into teacher preparation programs.]]>
