The Trade-off between Quality and Quantity: Evidence from a Field Experiment on Tutoring

High-dosage tutoring has the potential to substantially raise adolescent academic achievement, but schools may lack the resources to deliver small-group tutoring frequently at scale. This paper studies the relative importance of tutoring group size (quality) versus tutoring frequency (quantity) using a randomized controlled trial in a Midwestern U.S. charter middle school. Students were randomized to a control group, tutoring twice a week in 2-student groups, or tutoring three times a week in 3-student groups, with equal total cost per student across the two treatment arms. The results show that tutoring in 2-student groups led to a statistically significant improvement in math skills of 0.23 standard deviations, while the more frequent 3-student group tutoring did not produce significant gains. The findings suggest that, under budget constraints, smaller group size may be more effective than higher frequency.