Implementing a Collaborative-Inquiry learning Model to Foster 21st Century Critical Thinking: A Validity and Practicality Study for Sustainable Human Development

Introduction: Critical thinking skills are core competencies of the 21st century for individuals to solve complex problems, make data-based decisions, and adapt to rapid social, technological, and environmental changes. This condition indicates the need for innovative learning models to encourage active student involvement and develop critical thinking in a meaningful collaborative context. This study aims to evaluate the validity and practicality of the Collaborative-Inquiry Learning (Collin) model in developing 21st century critical thinking skills, which contribute to sustainable human development in the era of digital transformation.Method: The study was conducted in stages: preliminary study, prototype design, and formative evaluation. The products developed include model books, student’s book, and teacher’s book designed to support collaborative inquiry learning. Validation was carried out by education experts, colleagues, and practitioners, while the practicality test was obtained from teachers and students’ feedback.Results: The validation results showed a very high level of validity with an average score: model book (0.85), teacher’s book (0.85), and student’s book (0.82). The practicality from teachers resulted in a score of 89.27 for teacher’s and student’s book. The practicality from students resulted a score of 94.82 for student’s book. All instruments were declared feasible and relevant to be applied in 21st century learning.Conclusion: The Collaborative-Inquiry learning model is declared valid and practical to be applied in learning, especially in developing students’ critical thinking skills. This model supports active and reflective learning needed to form human resources that are adaptive, collaborative, and ready to face global challenges sustainably.