Experimental Design
Recruitment
Schools and classes interested in participating in the study were identified during the first half of the 2025–2026 school year. Participation was voluntary, and schools registered through the Ministry of Education.
All interested schools/classes received instructions to complete the pre-test and student questionnaire. The sample used for randomization consists of all classes that successfully completed the baseline assessments and surveys by the randomization deadline, excluding schools that no longer wished to participate in the programme (see details below).
Data collection
The impact of the intervention will be analysed by collecting data in both groups on: pupils' performance in mathematics and French; their motivation and self-efficacy, measured using validated scales; the classroom atmosphere and friendship networks, measured using validated scales; treatment fidelity (actions carried out by the pairs in the treatment group based on the workbooks distributed); two questionnaires for teachers (at midline and endline).
This data will be collected through pre- and post-tests and surveys using a platform developed for this purpose; it will ultimately be supplemented by the Ministry’s DEPP's national assessments at the beginning of CM1 and CM2. Longer-term monitoring of DEPP data may be considered if the results are conclusive.
Additionally, qualitative interviews with a number of teachers will be conducted to discuss the advantages and challenges of implementing tutoring in their classrooms.
All students will participate in the experiment as part of their Math and French classes. However, data will not be collected for students whose parents have refused the participation in the study.
Randomization
The randomization sample consisted of 78 schools and 92 classes that completed the baseline pre-tests and surveys.
Participating units were randomly assigned to one of two experimental conditions. In the Resources group (control), schools/classes receive French and mathematics workbooks for individual student use but do not implement peer-to-peer tutoring. In the Duos/Tutoring group (treatment), schools/classes receive workbooks containing the same exercises adapted for peer-to-peer tutoring and implement the Duos d’apprentissage tutoring programme.
The unit of randomization was the school whenever multiple eligible classes participated within the same school, in order to avoid within-school contamination. Otherwise, the participating class/school was randomized as a single unit.
Randomization was conducted in six batches to accommodate variation in the timing of baseline data collection. Within each batch, assignment was stratified by académie (a geographical administrative unit in the French education system). When a batch-académie cell contained more than seven schools, the stratum was further split by baseline academic performance, measured as the school-level average of students’ mathematics and French pre-test scores. We aimed to form strata of four schools where possible.
The final randomization procedure produced 20 strata. Six strata contained fewer than four schools. One school was randomized alone using a Bernoulli trial.
After randomization, one class dropped out of the evaluation before the teacher was informed of its assignment. This class belonged to a school with multiple participating classes, so this exclusion did not change the number of schools. One additional school dropped out after randomization but before learning its treatment status. Because both these dropouts occurred with no knowledge of the randomization status, it cannot bias the treatment allocation and we can take those two classes out of the analysis.
The final baseline sample therefore contains 77 schools, of which 38 are assigned to treatment and 39 to control, and 90 classes, of which 46 are assigned to treatment and 44 to control.