A Meta-Analysis of the Relation between Class Size and Achievement

Abstract

The purpose of this investigation was to examine the effects of Indiana's project PRIME TIME on reading and math achievement test scores of second graders who had completed 2 years of a state-supported reduced-class-size program. PRIME TIME reduced class sizes in grades K-3. The results of 10 studies yielding a total of 24 comparisons (3,967 scores) of PRIME TIME (small) and pre-PRIME TIME (large) classes were combined using Fisher's inverse chi-square procedure. Large classes averaged 26.4 students and small classes averaged 19.1 students. The results of this meta-analysis were significant at the .001 level. 10 comparisons (1,148 scores) were combined in a second meta-analysis for a control group in which class size was not reduced, and these results were not significant. The effect size for the PRIME TIME group was .34 standard deviations. This suggests that PRIME TIME students had higher achievement in basic skills after 2 years than did their cohorts in larger classes and indicates that primary children learn more effectively in smaller classes.