Class size reduction shows a negative, statistically non-significant effect on mathematics achievement (pooled SMD ‐0.03)¶

Claim · All claims
Evidence · 1 study · quant-synthesis r3 · q3
Currency · newest study 2018 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q3 i? The random-effects pooled standardised mean difference for mathematics is ‐0.03 (95% CI ‐0.22 to 0.16), negative and statistically non-significant, so a possible adverse impact on some students cannot be ruled out. → Filges 2018

Evidence¶

Filges 2018¶

Filges, T., Sonne‐Schmidt, C. S., Nielsen, B. C. V. (2018). Small class sizes for improving student achievement in primary and secondary schools: a systematic review. Campbell Systematic Reviews 2018:10. https://doi.org/10.4073/csr.2018.10

q3 · i? · quant-synthesis · r3

Meta-analysis of non-STAR studies of mathematics achievement using random-effects models; the pooled SMD was ‐0.03 (95% CI ‐0.22 to 0.16), with inconsistency in direction and magnitude across primary studies and no statistically significant effect.

"Primary study effect sizes for mathematics lies in the range ‐0.41 to 0.11. Two of the study‐level effects were statistically non‐significant. The weighted average was negative and statistically non‐significant."

Discussion¶

Related Claims¶

• Class size reduction produces a small, statistically significant positive effect on reading achievement by end of treatment year (pooled SMD 0.11) — related
• All four meta-analysable STAR studies report positive, statistically significant effects of small classes, but average effects are small — reports the opposite