https://www.sciencedaily.com/releases/2021/04/210407083628.htm

The review analyzed evidence from 205 studies, 186 of which were randomized controlled trials, to examine the effects of targeted school-based interventions on students' performance on standardized tests in reading and math.

Peer-assisted instruction and small-group instruction by adults were among the most effective interventions. The authors noted that these have substantial potential to boost skills in students experiencing academic difficulties.