The American Educational Research Journal has published a meta-analysis on the impact of tutoring programs on student academic achievement in preK-12. The study aims to show how the effects vary based on a range of characteristics. For inclusion in the review, studies had to use randomized designs and evaluate preK-12 tutoring interventions on learning outcomes measured through independent tests (i.e., not created by researchers/developers of the program). A total of 90 studies were included in the review. Of these, 72 studies measured literacy outcomes and 22 math outcomes. Most of the programs were delivered by a paraprofessional (43 studies), while the others were delivered by teachers and non-professionals or parents. The authors also coded the following characteristics to assess the variation in impact of tutoring: teacher-student ratio, setting, grade level, and the quality of the study design.
Overall, results showed significant positive effects of tutoring programs on student achievement (ES = +0.29) with larger effect sizes in kindergarten (ES = +0.41) and grade 1 (ES = +0.38) than grades 2-11. One-to-one tutoring had a larger effect (ES = +0.32) than small group tutoring (ES = +0.26). Tutoring provided by teachers was found to be more effective (overall ES = +0.39) than tutoring provided by paraprofessionals (ES = +0.30) and non-professionals (ES = +0.17), with the strongest difference in first grade.
On program delivery features, no difference was found between short and long duration (less or more than 20 weeks), while larger effects were found for intensity with 4-5 days/week of tutoring having a larger impact (ES = +0.35) than 1-3 days/week, however when tutoring was provided by a teacher, the effect for 3 days/week was higher. When tutoring was delivered in short sessions (less than 30 minutes; ES = +0.33) the impact was larger than when delivered in longer sessions (ES = +0.21). When tutoring was provided during the school time the effect was larger (ES = +0.31) than when provided after school (ES = +0.21).
