The Impact of Class Size Reduction on Student Achievement and Teacher Morale in Gambian Senior Secondary Schools West Coast Region

Abstract

This study employed an explanatory sequential mixed-methods design to investigate the impact of class size reduction on student academic achievement and teacher morale in Gambian senior secondary schools. The quantitative phase used a quasi-experimental, cross-sectional differential design with 360 Grade 11 science students and a correlational predictive design with 80 science teachers. The qualitative phase involved semi-structured interviews and classroom observations with 12 purposively selected teachers. The Integrated Science Achievement Test (ISAT) and the Science Teacher Morale and Efficacy Scale (STMES) were administered following rigorous pilot testing (ISAT KR20 = 0.84; STMES subscale α = 0.79–0.86). Independent samples t-tests revealed that students in reduced classes (≤35 students) significantly outperformed those in large classes (>55 students) on total ISAT scores (t(358)=9.85, p<.001, Cohen’s d=1.04), representing a very large educational effect size. Multiple regression analyses showed that class size was a strong negative predictor of instructional efficacy (β=0.492, p<.001) and workload satisfaction (β=0.614, p<.001), and a strong positive predictor of professional burnout (β=0.685, p<.001). Qualitative thematic analysis identified three major themes: abandonment of constructivist laboratory inquiry, excessive continuous assessment burdens, and chronic discipline problems leading to low instructional self-efficacy. The study concludes that classroom overcrowding constitutes a critical structural bottleneck undermining science education quality and teacher wellbeing in The Gambia. Recommendations include strategic infrastructural expansion, strict enrolment caps of 40 students per science section, differentiated teaching assignments with grading support, and targeted professional development in large-class pedagogy.