In the Pychometrik item parameter recovery simulation across 27 conditions (Grades K-8, sample sizes 500, 1,000, and 2,000), recovery accuracy increased with sample size and was best for Grade 8 simulees¶
Claim · All claims
Evidence · 1 study · designr2·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? Item recovery for Grade 8 was most accurate because its score distribution (mean 2.03) is closest to the mean item difficulty of 2.37, and higher sample size produced higher recovery accuracy. → He 2021
Evidence¶
He 2021¶
He, W., Bo, E., Meyer, P., & Grandgeorge, R. (2021). A comparison of item parameter estimates in Pychometrik and the existing item calibration tool. NWEA. https://www.nwea.org/research/publication/a-comparison-of-item-parameter-estimates-in-pychometrik-and-the-existing-item-calibration-tool/
q2 · i? · design · r2
Item parameter recovery simulation using MAP Growth Reading distributions across nine grades and three sample sizes (500, 1,000, 2,000), assessing bias, MAD, RMSE, and correlation between estimated and simulated parameters, reported in Figures 3.2-3.4.
"Item recovery for Grade 8 students has the best accuracy in all three figures. The Grade 8 score distribution has a mean of 2.03 (see Table 3.7), which is the closest to the mean item difficulty of 2.37 (see Table 3.8) compared to the other grades. Another observation is that the higher the sample size, the higher the accuracy of item parameter recovery."
Discussion¶
Related Claims¶
- When item difficulty and simulee ability ranges align (minimum -10, maximum 8), Pychometrik recovery is accurate, with correlations above 0.99 across all three sample sizes; recovery degrades above the simulee ability maximum of 7.94 — related
- In a fixed-person calibration simulation with 60 Rasch items and 1,200 simulees, estimates from both tools were comparable to true parameters, with the existing tool underestimating difficulty by 0.03 RIT on average — related
- Simulating higher-cognitive-ability students is easier: simulation quality correlates positively with student cognitive score — related
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
pychometrik-recovery-sample-size-and-grade-effects |
title |
In the Pychometrik item parameter recovery simulation across 27 conditions (Grades K-8, sample sizes 500, 1,000, and 2,000), recovery accuracy increased with sample size and was best for Grade 8 simulees |
description |
In the Pychometrik item parameter recovery simulation across 27 conditions (Grades K-8, sample sizes 500, 1,000, and 2,000), recovery accuracy increased with sample size and was best for Grade 8 simulees |
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 — he-2021 |
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