The effects of ability grouping versus mixed ability grouping on fourth grade mathematics achievement

The purpose of the study was to investigate the effects of ability grouping vs. mixed ability grouping on the mathematics achievement of high, medium, and low ability fourth grade students. Achievement was measured by mean growth on California Standardized Testing and Reporting (STAR) California Standards Tests (eSTs). The sample was composed of 704 fourth grade students from two elementary schools in the same Southern California school district. The research method chosen was a non-experimental quantitative retrospective study. Statistical analysis using a two-way ANOV A and t-tests was performed on three consecutive years oftest scores. Results showed that students of all ability levels experienced significantly higher achievement in homogeneously grouped classes. High ability students in heterogeneously grouped classes showed negative mean growth all three years of the study and medium ability students showed negative mean growth two of three years. Pacing, level of differentiation, and affect may play an important part in the effects of instructional grouping observed in the study. Keywords: ability grouping, homogeneous, heterogeneous, differentiation, pacing, affect, mathematics performance