Effect of Cooperative Learning Strategy on Students’ Achievement in Chemistry in Senior Secondary Schools in Lagos State

This study investigated the effect of cooperative learning strategy on students' achievement in Chemistry among senior secondary school students in Lagos State, Nigeria. The conventional lecture method remains dominant in many Nigerian Chemistry classrooms despite growing evidence supporting collaborative approaches in science education. A quasi-experimental design involving pretest-posttest control group arrangement was adopted for the study. Four intact SS2 Chemistry classes from four randomly selected public secondary schools in the Ikeja Education District were used, with two classes assigned to the experimental group and two to the control group. The experimental group was taught using cooperative learning techniques, including structured group tasks and peer evaluation, while the control group received traditional instruction. The Chemistry Achievement Test, comprising 40 multiple-choice items validated by subject experts, served as the primary instrument. Data analysis employed Analysis of Covariance to control for pre-existing differences. Results indicated that students in the cooperative learning group achieved significantly higher scores than their counterparts in the control group. Gender was not found to be a significant moderating variable. The study recommended that Chemistry teachers in Lagos State embrace cooperative learning as an evidence-based pedagogical approach and that teacher training programs integrate cooperative methodology modules. Keywords: cooperative learning, Chemistry achievement, secondary education, Lagos State, quasi-experiment.