Effects of Ability Grouping on Secondary School Students: A Meta-Analysis of Evaluation Findings

This article reports results from a meta-analysis of findings from 52 studies of ability grouping carried out in secondary schools. In the typical study the benefits from grouping were small but significant on achievement examinations—an average increase of one-tenth standard deviations on examination scores, or an increase from the 50th to the 54th percentile for the typical student in a grouped class. The size of achievement effect differed in different types of studies of grouping, however. Studies in which high-ability students received enriched instruction in honors classes produced especially clear effects, for example, while studies of average and below average students produced near-zero effects. The benefits of grouping were also clear in the area of student attitudes. Students in grouped classes developed more positive attitudes toward the subjects they were studying than did students in ungrouped classes.