A recent randomized evaluation conducted in Norway investigated the effects of a small group mathematics instruction on student academic achievement in elementary school. The study involved 159 elementary schools and 14,891 students in 10 municipalities in Norway. Schools were randomly assigned to receive the intervention or business as usual.
Students in the intervention group were pulled out from their regular math class into small groups homogenous for ability for 3-4 hours per week. Therefore, the small group instruction was delivered to all students in the class, not only to low-achieving students or pupils at risk for failure. The intervention lasts for one or two years with two periods of 4-6 weeks of intervention each year.
The authors evaluated the effects of the intervention on student mathematics achievement in fifth grade – after one or two years of intervention – through the Norwegian national test. Results showed significant positive effects for student math achievement (ES = +0.06). Although the long-term effect is small, the authors concluded that low-dosage small group tutoring can increase outcomes in mathematics for students of all ability levels.
Source (Open Access): Bonesrønning, H., Finseraas, H., Hardoy, I., Vaag Iversen, J. M., Nyhus, O. H., Opheim, V., Salvanes, K. V., Sandsør, A. M. J., & Schone, P. (2021). Small Group Instruction to Improve Student Performance in Mathematics in Early Grades: Results from a Randomized Field Experiment (SSRN Scholarly Paper ID 3979348). Social Science Research Network. https://doi.org/10.2139/ssrn.3979348