Average on-grade and all-grade item difficulty estimates differ by less than 0.1 logit for MAP Growth items¶
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? Across math, reading, and science, the average difference between on-grade and original all-grade item difficulty estimates is less than 0.1 logit (1 RIT). → 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 recalibrated 2,716 MAP Growth items with on-grade samples using the standard MAP Growth Rasch calibration procedure and compared the estimates to the original all-grade estimates. The report states the average differences "are less than 0.1 logit (i.e., 1 RIT)" across subjects and grades.
"are less than 0.1 logit (i.e., 1 RIT). The average on-grade item response counts ranged between 393 for reading and 643 for math, which accounted for the 19%–27% of the responses used to derive the original item difficulties."
Discussion¶
Related Claims¶
- Average drift in MAP Growth item difficulty estimates is negligible across subjects, with original-new correlations above 0.99 — 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
- 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
- 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
- Calibration sample size differences did not affect the size of on-grade versus all-grade item difficulty estimate differences — related
- Item calibration results from Pychometrik and the existing tool are mostly comparable across 1,180 AGC-calibrated MAP Growth items, with average RIT differences ranging from 0.33 (mathematics) to 0.91 (science) — related
- Old (English-borrowed) and newly calibrated Spanish item RITs differ negligibly, with correlations of 0.98 and no statistically significant paired t-test differences — related
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
map-growth-ongrade-allgrade-mean-difference-under-01-logit |
title |
Average on-grade and all-grade item difficulty estimates differ by less than 0.1 logit for MAP Growth items |
description |
Average on-grade and all-grade item difficulty estimates differ by less than 0.1 logit for MAP Growth items |
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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