Class size reduction produces a small, statistically significant positive effect on reading achievement by end of treatment year (pooled SMD 0.11)¶
Claim · All claims
Evidence · 1 study · quant-synthesisr1·q3·i1small
Currency · newest study 2018 · not yet checked against its sources · not reviewed by a person
Subclaims¶
Reading the evidence codes
q is the design tier, i the impact, n the sample, and the kind with its r
the rigour judged within that kind: what each code means.
This claim: no standardized effect is recorded in observations/ for it yet, so no benchmark reading is possible.
q3 i1 The random-effects pooled standardised mean difference for reading favouring small classes is 0.11 (95% CI 0.05 to 0.16), characterised as small. → 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 · i1 · quant-synthesis · r1
Meta-analysis of five non-STAR studies (USA, Netherlands, France; one RCT, five NRS; grades K–3 and grade 10) using random-effects inverse-variance weighting of Hedges' g. The pooled reading effect size was SMD = 0.11 (95% CI 0.05 to 0.16), "positive and statistically significant" and characterised as small.
"The weighted average was positive and statistically significant. The random effects weighted standardised mean difference was 0.11 (95% CI 0.05 to 0.16) which may be characterised as small."
Discussion¶
Related Claims¶
- Class size reduction shows a negative, statistically non-significant effect on mathematics achievement (pooled SMD ‐0.03) — related
- All four meta-analysable STAR studies report positive, statistically significant effects of small classes, but average effects are small — related
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
class-size-reduction-small-positive-reading-effect |
title |
Class size reduction produces a small, statistically significant positive effect on reading achievement by end of treatment year (pooled SMD 0.11) |
description |
Class size reduction produces a small, statistically significant positive effect on reading achievement by end of treatment year (pooled SMD 0.11) |
status |
review |
evidence_strength |
moderate |
newest_evidence |
2018 |
generated |
by process:wiki-ingest on 2026-10-08 |
trust |
unverified — no one has confirmed this page's content |
sources |
1 — filges-2018 |
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