EFFECT OF PROBLEM-BASED LEARNING ON STUDENTS' ACHIEVEMENT AND CRITICAL THINKING SKILLS IN SECONDARY SCHOOL CHEMISTRY IN SOUTH-SOUTH NIGERIA

This study examined the effect of Problem-Based Learning (PBL) on students’ academic achievement and critical thinking skills in secondary school chemistry in South-South Nigeria. The study adopted a quasi-experimental pretest–posttest non-equivalent control group design. The population comprised senior secondary school chemistry students, from which a sample of 120 students was drawn using intact classes from selected public secondary schools. Two instruments—Chemistry Achievement Test (CAT) and Critical Thinking Skills Test (CTST)—were used for data collection. The instruments were validated, and reliability coefficients of 0.82 and 0.85 were obtained respectively. Data were analysed using mean, standard deviation, and Analysis of Covariance (ANCOVA) at the 0.05 level of significance. The results revealed that students taught chemistry using PBL achieved significantly higher academic performance and demonstrated superior critical thinking skills compared to those taught using the conventional method. The findings further showed that PBL had a strong positive instructional effect even after controlling for pretest differences. The study concluded that Problem-Based Learning is an effective pedagogical approach for improving achievement and higher-order thinking skills in chemistry. It was recommended that PBL be integrated into secondary school chemistry curricula and that teachers be trained in learner-centred instructional strategies.