This paper presents the findings of a longitudinal, causal comparative investigation of an elementary school cluster grouping program. Both quantitative and qualitative methodologies were used. Although the cluster grouping program was originally designed to provide differentiation of content and instruction for gifted students, positive effects were also found on the achievement of all students in the school. During the three program years, students involved in the school using cluster grouping were more likely to be identified as high achieving or above average. Fewer students were identified as low achieving. A significant increase in achievement test scores of all students was found when these students were compared to similar students from a comparison school district. Qualitative analyses yielded three core categories—the use of grouping, the impact of teachers, and the general school environment—that helped to provide an understanding of the quantitative findings.
U022016