Haerul Salam, Fatchur Rohman, Aynin Mashfufah
The development of higher-order thinking skills and scientific literacy is a central goal of contemporary science education, particularly in Indonesia where instructional innovation is unevenly implemented. This study examined the effectiveness of STEM-based Project-Based Learning (STEM-PjBL) in improving elementary students’ critical thinking, creative thinking, and scientific literacy. A quasi-experimental pretest–posttest control group design was applied, involving experimental (STEM-PjBL) and control (conventional instruction) groups. Data were analyzed using both frequentist and Bayesian approaches, including Bayesian ANCOVA and Bayesian regression, to provide robust evidence of instructional effects. The findings indicated that students in the STEM-PjBL group showed significantly greater gains in all measured outcomes. Bayesian ANCOVA revealed very strong evidence for the effect of STEM-PjBL on critical thinking (BF = 15.15) and strong evidence on creative thinking (BF = 5.28). However, the direct effect on scientific literacy was weaker. Further Bayesian regression analysis showed that scientific literacy was best predicted by the combined contribution of critical and creative thinking (BF = 6.01), accounting for 51.2% of the variance. These results suggest that scientific literacy is primarily developed indirectly through the enhancement of higher-order thinking skills. Overall, the findings suggest that STEM-PjBL may serve as an effective instructional approach for supporting deeper cognitive development and meaningful science learning in Indonesia contexts. © 2026, Kura Publishing House. All rights reserved.
Basic Education, School of Postgraduate, Universitas Negeri Malang, Malang, Indonesia; Biology Department, Faculty of Mathematics and Natural Science, Universitas Negeri Malang, Malang, Indonesia
