There is a new Best Evidence in Brief with a follow-up study to an earlier post on a very popular theme: class size. Do note that the effect size is still pretty small for the high cost.

As in the U.S., French students from impoverished areas demonstrate lower achievement than their more affluent peers. In an effort to close this achievement gap, the French government issued a policy in 2017 reducing first grade class size in high-priority educational areas to no more than 12 students, extending to second grade classes and priority educational areas in 2018. In order to provide evidence regarding the feasibility of such a policy, researchers used data from a 2003 first-grade-class-size-reduction policy in France to examine its carryover effects into second grade.

The 2003 study involved assigning first grade classrooms to either small (12 students/class n=100 classes) or large (20-25 students/class, n=100 classes) class sizes. At the start of the 2002-03 school year, children were pretested on pre-reading skills and matched. In posttests at the end of the school year, results favored the small-class-size group on word reading (ES=+0.14) and word spelling (ES=+0.22). These effects are very small in light of the costs of halving class size.

The new study examined these students’ reading achievement at the end of second grade, where the students formerly placed in smaller first grades had been placed in full-sized classes again. Subjects were 1,264 students (663 E, 601C) who had received both the initial testing in first grade and had test scores at the end of second grade. Results showed that while both groups were equivalent at the start of first grade, and by the end of Grade 1 the small-class-size group showed greater academic achievement than the control group, this gain diminished over summer vacation and had completely disappeared by the end of Grade 2. That is, there was no long-term impact of one year of reduced class size.

Authors state that because reducing class size in first grade improved student achievement, and because these gains did not carry over into second grade when the students were placed in larger classes, class size reduction should be continued into second grade.

For more information, the original 2003 study was reported in Best Evidence in Brief in July.