Point measure correlations were unchanged by the difficulty adjustment because the new person ability estimates are linear transformations of the old ones¶
Claim · All claims
Evidence · 1 study · associationalr2·q2
Currency · newest study 2020 · checked against its sources 2026-10-20 (automated, 1 of 1 entry) · not reviewed by a person · overdue for a recheck since 2023: tool and model accuracy changes quickly
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? Old and new point measure correlation statistics remained the same for both Reading and Mathematics items in the follow-up study. → He 2020
Evidence¶
He 2020¶
He, W. (2020). MAP Growth K–2 item fit analysis: A follow-up study. NWEA. https://www.nwea.org/research/publication/map-growth-k-2-item-fit-analysis-study-a-follow-up-study/
q2 · i? · associational · r2
Summary statistics in Table 2.2 show identical rpm_new and rpm_old means (0.31) for both content areas and samples; the report attributes the invariance to the linear transformation of ability estimates.
"The old and new statistics for the point measure correlations remained the same for both Reading and Mathematics items in the follow-up study, which is expected as the new person ability estimates for each content area were obtained by applying a linear equation to the old person ability estimates."
Discussion¶
Related Claims¶
- New and old fit statistics are highly correlated after difficulty adjustment, with outfit correlations near 0.99 for Mathematics and infit correlations around 0.7 for Mathematics and mid-to-high 0.8–0.9 for Reading — related
- Adjusting MAP Growth K–2 item difficulties improved item fit, with old infit and outfit statistics more scattered than new ones in both samples — related
- New and old fit statistics are moderately correlated, with Pearson coefficients mostly between 0.50 and 0.79 — related
- Rescoring with new item parameters changed average ability estimates negligibly, with new and original scores correlated above 0.99 — related
- Learned difficulty parameters show a moderate positive correlation with empirical KC difficulty on QATD2k — related
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
map-k2-point-measure-correlations-unchanged |
title |
Point measure correlations were unchanged by the difficulty adjustment because the new person ability estimates are linear transformations of the old ones |
description |
Point measure correlations were unchanged by the difficulty adjustment because the new person ability estimates are linear transformations of the old ones |
status |
review |
evidence_strength |
moderate |
newest_evidence |
2020 |
source_checked |
2026-10-20 |
recheck_by |
2023 |
generated |
by process:wiki-ingest on 2026-10-08 |
trust |
unverified — no one has confirmed this page's content |
sources |
1 — he-2020 |
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