Coaching program effects shrink substantially at scale: effectiveness trials of larger programs show only a fraction of efficacy-trial effects¶

Claim · All claims
Evidence · 1 study · quant-synthesis r? · q2
Currency · newest study 2018 · checked against its sources 2026-10-20 (automated, 1 of 1 entry) · not reviewed by a person

Subclaims¶

q2 i? Graphical analysis by deciles of teacher sample size shows a clear negative relationship between program size and program effects for both instruction and achievement. → Kraft 2018

Evidence¶

Kraft 2018¶

Kraft, M.A., Blazar, D., Hogan, D. (2018). The effect of teacher coaching on instruction and achievement: A meta-analysis of the causal evidence. Review of Educational Research, 88(4), 547-588. https://doi.org/10.3102/0034654318759268

q2 · i? · quant-synthesis · r?

Figure 4 scatterplot of average effect size by deciles of teacher sample size with an overlaid OLS linear relationship, using teacher sample size as a proxy for program size; the pattern is descriptive, not a causal estimate.

"Graphs for both instruction (Panel A) and achievement (Panel B) depict a clear negative relationship between program size and program effects, consistent with a theory of diminishing effects as programs are taken to scale."

Discussion¶

Related Claims¶

• Pairing coaching with group trainings is associated with larger effects on instruction and achievement; instructional materials with larger, and video libraries with smaller, effects on instruction — the general claim this finding bears on, with the studies behind it

- Teacher coaching programs improve teachers' instructional practice by a pooled 0.49 SD across 43 causal studies — the general claim this finding bears on, with the studies behind it¶