Calibration sample size differences did not affect the size of on-grade versus all-grade item difficulty estimate differences¶
Claim · All claims
Evidence · 1 study · associationalr2·q2
Currency · newest study 2021 · not yet checked against its sources · not reviewed by a person · overdue for a recheck since 2024: 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? On-grade and original item difficulty estimates are highly correlated, and the correlation between calibration sample size difference and parameter estimate difference is small for most grades. → Wei He 2021
Evidence¶
Wei He 2021¶
Wei He, NWEA Psychometric Solutions. (2021). An Investigation of Item Parameter Invariance Using Focused Calibration Samples for MAP Growth. NWEA. https://www.nwea.org/research/publication/an-investigation-of-item-parameter-invariance-using-focused-calibration-samples-for-map-growth/
q2 · i? · associational · r2
Study 1 computed correlations between on-grade and original estimates (Table 3.2); the report describes these as close to 1 for most grades and states the sample-size correlations "did not affect the difference between the on-grade and the original item difficulty estimates."
"implying that the calibration sample sizes used to derive the on-grade and the original item difficulties did not affect the difference between the on-grade and the original item difficulty estimates."
Discussion¶
Related Claims¶
- For items aligned to multiple target grades, difficulty estimates from different on-grade calibration samples differ negligibly, at most 0.1 logit on average — related
- Average on-grade and all-grade item difficulty estimates differ by less than 0.1 logit for MAP Growth items — related
- At least 90% of reading and science items and about 80% of math items show difficulty differences within 0.3 logits between on-grade and all-grade calibration — related
- Item difficulty estimates from target-plus-adjacent-grade samples generally differ from original estimates about as much as on-grade estimates do, with mean differences within 0.11 logit — related
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
map-growth-sample-size-did-not-affect-difficulty-differences |
title |
Calibration sample size differences did not affect the size of on-grade versus all-grade item difficulty estimate differences |
description |
Calibration sample size differences did not affect the size of on-grade versus all-grade item difficulty estimate differences |
status |
review |
evidence_strength |
moderate |
newest_evidence |
2021 |
recheck_by |
2024 |
generated |
by process:wiki-ingest on 2026-10-08 |
trust |
unverified — no one has confirmed this page's content |
sources |
1 — wei-he-2021 |
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