Matthew A. Kraft and colleagues conducted a meta-analysis of the causal evidence on the effect of teacher coaching on teaching and learning. Their paper, published in the Review of Educational Research, reviewed 60 studies on teacher coaching programs conducted after 2006 that measured the impact of teacher coaching on either teaching (measured using tools such as the Classroom Assessment Scoring System or the Early Language and Literacy Classroom Observation) or student academic performance (measured by standardized tests).
Their results found that
- Sustained coaching improves both classroom teaching (ES= +0.49) and student achievement (ES=+0.18).
- The effectiveness of a teacher coaching program seems to be determined by the number of participants. When studies were divided into programs that had fewer than 100 participants and those that had more than 100 participants, the impact on teaching was nearly double for the smaller programs than for programs with more than 100 participants.
- For student achievement, the smaller programs showed an impact of nearly three times that of the larger programs.
The authors remarked that more knowledge was needed on whether teacher coaching was best implemented as a smaller scale targeted program tailored to local contexts or if it could scale up in a high-quality and cost-effective way.