The Ministry of Education in France instituted a policy in 2002 that reduced class size to no more than 12 students in areas determined to have social difficulties and high proportions of at-risk students, called Zones d’Education Prioritaire (ZEP). In order to evaluate the effectiveness and usefulness of this policy, researcher Jean Ecalle and colleagues in France examined the results of the policy-mandated class size reduction on the reading achievement of first graders (Study 1), and compared them to the effects of an evidence-based literacy intervention on the reading achievement of at-risk children in regularly sized classes (20 students) (Study 2).

Study 1, reducing class size, involved assigning classrooms to either small (12 students/class n=100 classes) or large (20-25 students/class, n=100 classes) class sizes (with the support of the Ministry). At the start of the 2002-03 school year, 1,095 children were pretested on pre-reading skills and matched at pretest.

In Study 2, researchers separated 2,803 first graders in ZEP areas into an experimental group who received an evidence-based reading intervention, and a control group who did not. The intervention was a protocol developed by the Association Agir pour l’Ecole (Act for School), who developed a hierarchy of teaching reading based on evidence-based methods of learning to read, progressing from training phonological skills, to learning letter sounds, decoding, and fluency. Act for School monitored compliance with the protocol weekly. Class size for both groups was 20 students. Experimental teachers received a one-day training, and provided 30 minutes of instruction a day to average or high readers in groups of 10-12, and one hour a day for lower readers in groups of 4-6.

Students in the two studies were pre-tested on reading skills and matched between groups:

• The post-test results of study 1 favored the small-class-size group on word reading (ES=+0.14) and word spelling (ES=+0.22).
• The post-test results of study 2 favored the experimental group, with significant effects on word reading (ES=+0.13) and word spelling (ES=+0.12).

Researchers stated that based on the results of both studies, the optimal recommendation to improve literacy skills for at-risk students would be a double intervention, combining evidence-based practices within small classes.

Source: Ecalle, J., Gomes, C., Auphan, P., Cros, L., & Magnan, A. (2019). Effects of policy and educational interventions intended to reduce difficulties in literacy skills in grade 1. Studies in Educational Evaluation, 61, 12–20.