Relationship Between Class Size and Science Teaching Effectiveness in Junior Secondary Schools in Borno State

This study examined the relationship between class size and Science teaching effectiveness in junior secondary schools in Borno State, Nigeria. Overcrowded classrooms have been persistently flagged as a structural impediment to quality education in Nigerian schools, yet empirical data specific to science teaching effectiveness in the North East context is limited. A descriptive correlational research design was employed. The study covered 180 JS2 Science classes across Maiduguri, Jere, and Konduga Local Government Areas. Class enrolment records and a validated Science Teaching Effectiveness Scale, completed by both teachers and students, were used as instruments. Reliability was confirmed at 0.77. Pearson's correlation and regression analysis were used to explore the relationship. Results revealed a significant negative correlation between class size and teaching effectiveness scores, indicating that as class size increased beyond 45 students per class, teacher interaction quality, use of practical activities, and individual assessment declined markedly. Classes with 30 to 40 students recorded the highest effectiveness ratings. Recommendations included immediate recruitment of additional Junior Science teachers, redistribution of student enrolments across available classes, and construction of additional classroom blocks to reduce class congestion. Keywords: class size, teaching effectiveness, junior secondary schools, Borno State, science instruction.