Title | Ability Grouping and Student Achievement in Elementary Schools: A Best-Evidence Synthesis
Author | Slavin, R. E.
Source | Review of Educational Research, 57 (3), 293-336
Year Published | 1987
Review of research of between-class and within-class ability grouping on the achievement of elementary students. The review technique–best-evidence synthesis–combines features of meta-analytic and narrative reviews.
Overall, the evidence does not support assignment of students to self-contained classes according to ability (median ES = 0.00), but grouping plans involving cross grade assignment for selected subjects can increase student achievement. Research particularly supports the Joplin Plan, cross-grade ability grouping for reading only (median ES = 0.45). Within class ability grouping in mathematics is also found to be instructionally effective (median ES = 0.34). Ability grouping is maximally effective when done for only one or two subjects, with students remaining in heterogeneous classes most of the day; when it greatly reduces student heterogeneity in a specific skill; when group assignments are frequently reassessed; and when teachers vary the level and pace of instruction to students’ needs. Ability grouping appears most effective for specific subjects with students remaining in heterogeneous classes most of the day. Cross-grade assignment for selected subjects can increase achievement.
Ability grouping of students has a substantial history of use in elementary and secondary schools. There are two commonly used types of ability grouping: between-class* and within-class* ability grouping. Between-class ability grouping is a school-level practice; it refers to forming classrooms so that students of similar ability are placed together. Within-class grouping is a teacher-level practice, where a teacher groups students of similar ability together within a single class. There has been an on-going debate in education about whether or not ability grouping helps or harms student achievement.
The argument in favor of ability grouping is that it allows teachers to challenge high-achievers, while providing remediation, repetition and review for low-achievers. Proponents of ability grouping claim that in mixed ability classrooms teachers have to teach to the average level, which bores the high-achievers and is too fast paced for the low achievers, thereby creating an ineffective educational environment for most of the children in the class.
The arguments against ability grouping usually focus on its negative impact on low-achievers, who, when separated from their high-achieving peers, suffer the double blow of losing the positive example of their peers and suffering lowered-expectations from their teachers. In addition, some researchers believe that low-achieving groups are likely to receive lower quality instruction than high-achieving groups, further increasing the achievement gap. This meta-analysis examines not only whether ability grouping is effective, but also whether students benefit more or less from ability grouping depending on the academic subject it is used in, or the type of ability grouping plan being implemented.
What are the effects of between- and within-class grouping practices on the academic achievement of elementary school students?
Best-Evidence Synthesis (combines elements of meta-analysis and narrative reviews)
- Number of Studies Included | 43 studies in total
- 14 studies of comprehensive ability-grouped class assignment plans
- 7 studies of ability grouping for selected subjects (i.e. reading and math)
- Number of Subjects | N/A
- Years Spanned | 1936-1986
Elementary school students in classrooms which divided children by ability groups.
Age/Grade of Subjects
Students ranged from 1st through 6th grade.
Specific disabilities were not reported, but many ability groups were split by high, average, or low IQ/achievement.
Students were grouped by ability in different subjects. Some ability grouping was done within a single class, while other studies looked at ability grouping between grades.
Duration of Intervention
All studies lasted at least one semester.
- Overall, the evidence does not support assignment of students to self-contained classes according to ability.
- However, grouping plans involving cross-grade assignment for selected subjects can increase student achievement. Research particularly supports the Joplin Plan, a cross-grade ability grouping plan for reading only. Within-class ability grouping in mathematics was also found to be effective.
- Ability grouping is most effective when done for only one or two subjects, with students remaining in heterogeneous/mixed-ability classes most of the day.
- Ability group assignments should be frequently reassessed and teachers should vary the level and pace of instruction to students’ needs.
Combined Effects Size
The median Effect Size (ES) of assigning students to self-contained classes according to ability was 0.00, meaning that it was neither beneficial nor detrimental. Ability grouping overall simply had no effect on the students. The Joplin Plan (a cross-grade ability grouping program for reading only) had a moderate median effect size of 0.45. Within class ability grouping in mathematics had a median effect size of 0.34.
Slavin concludes that schools and teachers should use ability grouping methods proven most effective, such as within-class ability grouping in mathematics and the Joplin Plan, a cross-grade ability grouping plan in reading. Some tips for successful ability grouping include:
- Encourage students to identify primarily with the whole heterogeneous* class. Only regroup students by ability when being with similar ability-level peers is particularly important for learning, as is the case with math or reading instruction;
- Allow for different levels of IQ and overall achievement levels within different subject specific ability groups;
- Choose grouping plans that allow for frequent reassessment of student placement and for easy reassignment based on student progress;
- Vary the level and pace of instruction according to students’ needs, levels of readiness, and learning rates in regrouped classes;
- Keep the number of within-class ability groups small, so the teacher will be able to provide adequate direct instruction for each group;
- Only reduce student heterogeneity in the specific skill being taught such as reading or math, allow students to work with students of varying ability levels for most of the day.