Implementation of Problem-based Learning Model to Improve Students' Critical Thinking Skills: The Case of Christian University of Indonesia

Critical thinking skills are one of the essential competencies of the 21st century that students must possess to face complex global challenges and support logical and rational decision-making. However, in higher education, the still-dominant conventional learning methods tend to be less effective in stimulating students' critical thinking skills. Therefore, learning models that can activate higher-order thinking processes are needed, one of which is the Problem-Based Learning (PBL) Model. This study aims to determine the effect of implementing the Problem-Based Learning Model on improving students' critical thinking skills. The study used a quasi-experimental design with a non-equivalent control group design approach. The sample consisted of two classes of fourth-semester chemistry education students, each as an experimental group taught using the PBL model and a control group using the conventional model. The research instrument was a critical thinking test with indicators of interpretation, analysis, evaluation, and inference, which was analyzed using paired and independent sample t-tests. The results showed a significant increase in critical thinking skills in the experimental group compared to the control group. The average critical thinking score in the experimental group increased from 62.1 to 84.7 with an N-Gain of 0.62 (moderate category), while the control group only experienced an increase from 61.8 to 70.5 with an N-Gain of 0.28 (low category). The indicator that experienced the highest increase was analysis and inference. It can be concluded that the implementation of the PBL model can significantly improve students' critical thinking skills. This model is recommended for widespread implementation in higher education to optimally develop students' higher-order thinking skills.