Claims

Contextual-mean effects show little moderation by individual achievement; apparent positive moderation is illusory when the quadratic term is omitted

Claim · All claims
Evidence · 1 study (2 entries) · associational r2 · q2
Currency · newest study 2026 · 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.

q2 i? In the fully specified curvature-adjusted model, the L1 × L2 interaction was small and slightly negative, opposite to the ordinal-standing prediction of a positive attenuating interaction. → Herbert W. Marsh 2026 q2 i? Omitting the quadratic term produced an apparently moderate positive interaction that largely disappeared once curvature was modeled. → Herbert W. Marsh 2026 (2)

Evidence

Herbert W. Marsh 2026

Herbert W. Marsh. (2026). Four Decades After the Big-Fish–Little-Pond Effect: Critical Boundary Tests and Integrative Models of Mean-Context, Ordinal-Standing, and Distributional-Scaling in 46 Countries. Educational Psychology Review. https://doi.org/10.1007/s10648-026-10200-0

q2 · i? · associational · r2

Multilevel Model 5 (L1, L2, L1², L1 × L2) in the TIMSS 2019 sample: the interaction was "small and slightly negative (β = −0.052, SE = 0.006)", providing little evidence that the contextual effect weakens at higher achievement levels.

"In the fully specified curvature-adjusted model (Model 5), the interaction was small and slightly negative (β = −0.052, SE = 0.006). Figure 1D shows that the contextual-effect profiles remained close to parallel across levels of individual achievement."

Herbert W. Marsh 2026 (2)

Herbert W. Marsh. (2026). Four Decades After the Big-Fish–Little-Pond Effect: Critical Boundary Tests and Integrative Models of Mean-Context, Ordinal-Standing, and Distributional-Scaling in 46 Countries. Educational Psychology Review. https://doi.org/10.1007/s10648-026-10200-0

q2 · i? · associational · r2

Model 4 (without L1²) in the same sample produced "an apparently moderate positive interaction (β = 0.153, SE = 0.003)"; the article attributes this to illusory moderation arising from omitted nonlinear terms.

"The importance of modeling curvature is illustrated by Model 4, where omission of the quadratic term produced an apparently moderate positive interaction (β = 0.153, SE = 0.003) and the fan-shaped pattern visible in Fig. 1C. Once the quadratic term was included, however, the apparent moderation largely disappeared."

Discussion

Learner Variables

Page metadata
Field Value
type claim
id bflpe-moderation-by-achievement-small-and-illusory
title Contextual-mean effects show little moderation by individual achievement; apparent positive moderation is illusory when the quadratic term is omitted
description Contextual-mean effects show little moderation by individual achievement; apparent positive moderation is illusory when the quadratic term is omitted
status review
evidence_strength moderate
newest_evidence 2026
generated by process:wiki-ingest on 2026-10-21
trust unverified — no one has confirmed this page's content
sources 2 — herbert-w-marsh-2026, herbert-w-marsh-2026-2

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