Effect of Class Size on Students Academic Achievement and Retention in Mathematics in Umuahia North Local Government Area Abia State

The study investigated the effects of class size on students’ academic achievement and retention in Mathematics in Umuahia North Local Government Area, Abia State. Three research questions and three corresponding hypotheses guided the study. A quasi-experimental, non-randomized pre-test–post-test design was adopted. The population comprised 1,753 Senior Secondary School One (SS1) students, while a sample of 102 students was selected using simple random sampling. Data were collected using the Mathematics Achievement Test (MAT), and the study lasted three weeks. Mean and standard deviation were used to answer the research questions, while Analysis of Covariance (ANCOVA) was employed to test the hypotheses. The findings revealed that teaching Mathematics in small classes was significantly more effective than teaching in large classes in improving students’ academic achievement and retention. Both male and female students benefited from small-class instruction. Based on these findings, the study recommends that Mathematics teachers adopt smaller class sizes to promote meaningful learning, improve academic performance, and develop positive attitudes towards Mathematics. Furthermore, teacher-training programmes, seminars, workshops, and conferences should emphasize effective teaching strategies for small classes. The government and relevant professional bodies, including the Science Teachers Association of Nigeria (STAN), should promote manageable class sizes. Additionally, the Ministry of Education should establish appropriate student admission limits for schools to facilitate effective Mathematics teaching and learning.