Average drift in MAP Growth item difficulty estimates is negligible across subjects, with original-new correlations above 0.99¶
Claim · All claims
Evidence · 1 study · associationalr2·q2
Currency · newest study 2022 · checked against its sources 2026-10-20 (automated, 1 of 1 entry) · not reviewed by a person · overdue for a recheck since 2025: 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? Re-estimation of items calibrated at least four years earlier yielded average difficulty changes of 0.03, -0.03, 0.06, and 0.02 logit in math, reading, language usage, and science, with original-new correlations above 0.99 in all four subjects. → He 2022
Evidence¶
He 2022¶
He, W. (2022). MAP Growth item parameter drift study. NWEA Research Report. https://www.nwea.org/research/publication/map-growth-item-parameter-drift-study/
q2 · i? · associational · r2
Item recalibration of items analyzed after excluding those with fewer than 1,000 responses, using the post-June 2021 calibration procedure on Fall 2017–Spring 2019 test events. The report calls these changes "quite small" and notes the difficulty difference distributions are normal and symmetrical around zero.
"The average change in item difficulty estimates was 0.03, -0.03, 0.06, and 0.02 logit in math, reading, language usage, and science, respectively."
Discussion¶
Related Claims¶
- Rescoring with new item parameters changed average ability estimates negligibly, with new and original scores correlated above 0.99 — related
- Students encountered substantial numbers of items with changed parameter estimates, averaging 11–38% of test length by subject — related
- Both item-level and test-level analyses indicate the MAP Growth measurement scales are remaining stable — a broader claim this one bears on
- Average on-grade and all-grade item difficulty estimates differ by less than 0.1 logit for MAP Growth items — related
- Flagged items showed no clear pattern by original difficulty, spreading across the entire scale like unflagged items — related
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
map-growth-average-difficulty-drift-negligible |
title |
Average drift in MAP Growth item difficulty estimates is negligible across subjects, with original-new correlations above 0.99 |
description |
Average drift in MAP Growth item difficulty estimates is negligible across subjects, with original-new correlations above 0.99 |
status |
review |
evidence_strength |
moderate |
newest_evidence |
2022 |
source_checked |
2026-10-20 |
recheck_by |
2025 |
generated |
by process:wiki-ingest on 2026-10-08 |
trust |
unverified — no one has confirmed this page's content |
sources |
1 — he-2022 |
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