Small classes don’t close achievement gap: study |
By Paul Heiser
Research Analyst
While studies consistently show that small classes improve average overall academic achievement of students, a new study finds that small classes don’t close the achievement gap between lower-performing and higher-performing students.
The results do not indicate that low achievers are better off in regular classes, according to the study. Rather, all types of students benefit from being in small classes, but the small class effect was consistently greater for high achievers than for other students.
The study, “Do Small Classes Reduce the Achievement Gap between Low and High Achievers? Evidence from Project STAR,” was conducted by Spyros Konstantopoulos, a professor at North-western University. Konstantopoulos examined the differences in achievement between small and regular classes as well as differences in achievement of students within those classes.
The analysis used data from the well-known Project STAR study. Project STAR was a four-year large-scale randomized experiment conducted in Tennessee in the mid-1980s that found that students in smaller classes, as a whole, performed better in math and reading than did students in larger classes or larger classes with a teacher aide.
That study sample consisted of nearly 11,000 elementary school students from 79 elementary schools in 42 districts who participated in the experiment from kindergarten to grade 3. During the first year of the study, kindergarten students within each school were assigned randomly to classrooms in one of three treatment conditions: smaller classes (13-17 students), larger classes (22-26 students) or larger classes with a full-time classroom aide.
Teachers were also assigned randomly to classes of different types. The assignments of students to classroom types were maintained through the third grade for students who remained in the study. Teachers at each subsequent grade level were also assigned randomly to classes as the experimental cohort passed through grades.
Project STAR measured the effects of small classes on reading and math by looking at the results of students on Stanford Achievement Tests.
Overall, the results indicate that class size reduction increased not only achievement for all students on average, but the variability among higher and lower achieving students as well. Differences in achievement due to reduced class sizes were observed for both math and reading mainly during the first two years of the study (kindergarten and first grade). The differences favoring small classes were more pronounced and significant in the first two years of the experiment (kindergarten and grade 1) and smaller and less significant in the last two years of the experiment (grades 2 and 3).
The study offered several possible explanations for these findings. One possible explanation was that teachers were more likely to identify higher-achieving students in small classes and thus were more likely to provide effective strategies that benefit these students more.
Another possible explanation was that instructional practices in small classes benefit higher achievers more because those students may be more engaged in learning than other students in small classes. High achievers may take more advantage of the opportunities or teacher practices that take place in small classes or create more opportunities for learning in small classes than lower achieving students.