The study reported in this paper quantitatively integrated the recent research findings on ability grouping in order to generalize about these effects on student achievement and student self-concept. Meta-analysis was used to statistically integrate the empirical data. The relationships among various experimental variables including grade level, sex, race/ethnicity, ability level of students, the subject matter being taught, the length of time students were grouped, and the effects of ability grouping were investigated. The relationships among various study characteristics including publication data, school size data, school socio-economic status, school geographic location, school curriculum information, the number of ability levels, measurement information, experimenter information, internal validity and the effects of ability grouping were investigated. The major findings of this study, based on 720 measurements derived from experimental data in 50 studies reported between 1967 and 1983, were that students who were ability grouped had the same cognitive outcome scores as students who were not ability grouped, and had lower affective outcome scores than students who were not ability grouped. The findings indicated not only that the practice of ability grouping does not increase student achievement, but also that ability grouping has adverse effects on students' self-concept. A bibliography containing nine citations from 1971 to 1985 is included. (Author/PN)