Ability Grouping:
Helpful or Harmful?
Mary Ann Swiatek, Ph.D.
Licensed Psychologist
swiatek@rcn.com
Definitions
Ability grouping: Placing students
in learning groups with others of
similar aptitude; can vary by
subject; can be flexible over time
Tracking: Assignment of students
to one group for all subjects,
based on a measure of general
ability (e.g., IQ)
The Arguments
For: Helps teachers focus the
level of the presentation
Against:
Reduces expectations of lowerability students
Discriminates against minority
students
Promotes inequity
The Evidence:
Meta-analyses
Quantitative summaries of
research results
General steps:
Stipulate methodological criteria a
study must meet to be included
Locate as many qualifying studies
as possible
Quantify the results of the studies in
terms of effect sizes
The Evidence:
Meta-analyses
Effect size:
A common metric allowing
comparison of results across studies
Quantifies magnitude of results in
standard deviation units
Range: -3.00 to +3.00
(approximately)
The Evidence:
Meta-analyses
Classification:
 Below 0.2: Negligible
 0.2 to 0.5: Small
 0.5 to 0.8: Medium
 Above 0.8: Large
The Evidence:
Meta-analyses
Problems with the evidence
Some meta-analyses use only
studies that randomly assign
students to groups
Some meta-analyses discount
findings if curriculum is modified
for different groups
The Results:
Gifted Students
Gifted students achieve
better in ability groups
In elementary school:
 28 studies of achievement test
scores: Average ES = .19 (.49 in 9
studies of programs designed for
G&T, .07 in 19 studies of broad
programs)
The Results:
Gifted Students
In high school:
 51 studies with “measured
outcomes” had average ES = .10
(.33 in the 14 studies of classes
designed for G&T students, .02 in
33 studies of broad programs)
The Results:
Gifted Students
Elementary and high school
together:
 78 studies of achievement test
scores
Average ES = .15
For honors classes (N = 25),
ES = .33
For “XYZ grouping” ES = .12 for
high ability students
The Results:
Gifted Students
 23 studies of homogeneous vs.
heterogeneous classrooms
Standardized achievement tests:
 ES = 0.4 for science, social
studies, and total
 ES <0.25 for math, reading, and
writing
 ES = 0.4 favoring
heterogeneous classes for
languages
The Results:
Gifted Students
Bigger effects for teacher-made
tests
 All favored homogeneous
classes
 ES = 1.0 for math and science
 “Large” ES for English and
social studies
The Results:
Low-Ability Students
Low-ability students’
academic achievement in
ability groups is equal to or
better than in heterogeneous
settings.
Effect sizes are negligible to
small (-0.02 to 0.29).
The Results:
Low-Ability Students
In high school:
 4 studies with “measurable
outcomes:” Average ES “near
zero” for programs designed for
academically deficient
students
The Results:
Low-Ability Students
In elementary and high school
together:
 For remedial programs (N = 4),
ES = .14
 In XYZ grouping (N = 39), ES was
“virtually zero”
The Results:
Across Ability Groups
Elementary school:
Effects near zero for “compre-
hensive ability grouping”
14 studies (1959-1968) of “Joplin
plan” grouping in reading:
ES = .45
8 studies of within-class grouping
for math: ES = .32
The Results:
Across Ability Groups
High School
29 studies of tracking: No
effect
The Results:
Cooperative Groups
In middle school:
High achieving students
achieve more in heterogeneous cooperative groups
than in individual learning?
…but more in homogeneous
than heterogeneous
cooperative groups?
The Results:
Ability Grouping vs. Tracking
Remember definitions
Ability grouping is associated
with increased performance;
tracking is not
The Results:
Curriculum Modification
Effectiveness of ability
grouping corresponds to the
extent to which curriculum is
modified to meet the needs
of the group
The Results:
Social/Emotional Adjustment
Often cannot be subject to
meta-analysis
Many studies do not include
these variables
Those that do are not
consistent in what variables are
included or how they are
measured
The Results:
Social/Emotional Adjustment
Most meta-analyses find
negligible effects of grouping
In elementary school:
9 studies of “self-esteem
(apparently global)
Average ES = .06
No separate data for gifted
students (probably due to small
N)
The Results:
Social/Emotional Adjustment
In high school:
15 studies of “self-concept”
Average ES = .01
No separate data on gifted
students
8 studies of attitudes toward
subject matter: ES = .37
11 studies of attitudes toward
school: Average ES = .09
The Results:
Social/Emotional Adjustment
In elementary and high school
together:
 24 studies of “self-esteem”
Average ES “near zero”
Honors classes (N = 6) ES
“trivial”
XYZ programs: ESs negligible
Remedial programs (N = 3):
ES = .33
The Results:
Social/Emotional Adjustment
 Subset (not clear how many) of 23
studies of homogeneous vs.
heterogeneous classrooms
ES = 0.09 for self-concept
ES = -0.02 for creativity
“Positive effect” (ES not
specified) for attitude toward
school
ES = -.46 for attitude toward
peers
So, In General…
Gifted students achieve better in
ability groups when curriculum is
modified for them
Low-ability students achieve
about the same with or without
grouping
Ability grouping for gifted
students is supported by
research; tracking is not
So, In General…
Homogeneous cooperative
groups may be more effective
than heterogeneous ones.
Grouping typically is found to
have no effect on
social/emotional adjustment
References
 Goldring, E. B. (1990). Assessing the
status of information on classroom
organizational frameworks for gifted
students. Journal of Educational
Research, 83(6), 313-326.
 Kulik, C-L. C. & Kulik, J. A. (1982).
Effects of ability grouping on
secondary school students: A metaanalysis of evaluation findings.
American Educational Research
Journal, 19(3), 415-428.
References
 Kulik, C-L. C. & Kulik, J. A. (1984). Effects
of ability grouping on elementary
school pupils: A meta-analysis. Paper
presented at the annual meeting of the
American Psychological Association,
Toronto, Ontario, Canada. (ERIC
Document Reproduction Service No.
ED 255329)
References
 Kulik, C-L. C. (1985, August). Effects of
inter-class ability grouping on
achievement and self-esteem. Paper
presented at the annual meeting of the
American Psychological Association,
Los Angeles, CA. (ERIC Document
Reproduction Service No. ED 263492)
References
 Neber, H., Finsterwald, M., & Urban, N.
(2001). Cooperative learning with
gifted and high-achieving students: A
review and meta-analysis of 12 studies.
High Ability Studies, 12(2), 199-214.
 Slavin, R. E. (1987). Ability grouping and
student achievement in elementary
schools: A best-evidence synthesis.
Review of Educational Research, 57(3),
293-336.
References
 Slavin, R. E. (1990). Achievement
effects of ability grouping in
secondary schools: A bestevidence synthesis. Review of
Educational Research, 60(3), 471499.