In order to control spending and keep costs down, education policymakers often decide to increase class sizes. But what impact does this have on the academic ability and achievements of children?
A 110-page report by Campbell Collaboration attempts to lift the lid on class sizes and their effect on student learnings in both primary and secondary schools.
This systematic review summarises findings from 148 reports from around the world. Ten studies were also included in the meta-analysis. A total of 127 studies, consisting of 148 papers, met the inclusion criteria. These 127 studies analysed 55 different populations from 41 different countries.
Here’s what the research found…
General consensus about class size
The vast majority of those in education research believe that smaller classes are effective in student achievement. As a result, a number of US states, the UK, and the Netherlands have changed policy to reduce class sizes.
However, that doesn’t mean to say everybody shares the same sentiment. Some argue that the effects of class size reduction are only modest, with more cost-effective strategies available to improve educational standards.
Research results and conclusions
Whereas one strand of class size research suggests that smaller numbers can lead to positive and significant improvements, another points to small and insufficient effects.
In this review, the intervention has been class size reduction, meaning that studies only considering average class size measuring a student-teacher ratio at school level (or higher levels) were not included.
As the author’s conclusion explains:
“There is some evidence to suggest that there is an effect of reducing class size on reading achievement, although the effect is very small,” said Trine Filges, Christoffer Scavenius Sonne-Schmidt, Bjørn Christian Viinholt Nielsen.
“We found a statistically significant positive effect of reducing the class size on reading. The effect on mathematics achievement was not statistically significant, thus it is uncertain if there may be a negative effect.”
What does this mean for schools?
Essentially, class size reduction is a costly exercise, with the available evidence pointing to no or only very small effect in sizes of small classes when compared to larger classes.
Even when you take the individual variation in effects into consideration, it is difficult to rule out the possibility that small classes may be counterproductive for some students.
Therefore, it would help to know more about the relationship between class size and achievement, particularly how it influences what teachers and students do in the classroom. That way, money can be allocated in the best possible areas.
- The evidence suggests smaller class sizes result in a small effect on reading achievement
- There is a negative but statistically insignificant effect on mathematics
- Actually implementing a reduction in class size is expensive and not always cost-effective
- No or only small effect in sizes of small classes when compared to larger classes
- In certain instances or scenarios, small classes may be counterproductive for some students
For more, here’s the report in full – Small class sizes for improving student achievement in primary and secondary schools: a systematic review.