CTT and MFRM yield a positive, perfect correlation between item difficulty indices for open-ended items under a crossed design¶
Claim · All claims
Evidence · 1 study · associationalr2·q3
Currency · newest study 2018 · not yet checked against its sources · not reviewed by a person · overdue for a recheck since 2021: 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.
q3 i? Item difficulty indices estimated according to CTT and MFRM for ten open-ended mathematics items correlate positively and perfectly (r = .999, p<.001). → Ilhan 2018
Evidence¶
Ilhan 2018¶
Ilhan, M., & Guler, N. (2018). A Comparison of Difficulty Indices Calculated for Open-Ended Items According to Classical Test Theory and Many Facet Rasch Model. Eurasian Journal of Educational Research, 75. doi:10.14689/ejer.2018.75.6
q3 · i? · associational · r2
Correlational analysis of difficulty indices computed for ten open-ended items from ratings of 375 eighth graders by three teachers; CTT indices via Excel, MFRM via FACETS. The chart reports "r = .999, p<.001".
"Spearman’s correlation coefficient shown at the bottom of Chart 1 suggests that there is a positive and perfect correlation between item difficulty indices estimated in CTT and MFRM."
Discussion¶
Related Claims¶
- CTT and MFRM yield similar item difficulty results for open-ended questions regardless of crossed or nested design — a broader claim this one bears on
- Items ranked from easiest to most difficult are identical under CTT and MFRM — related
- Scorer severity and standard difficulty were statistically adjusted using Many-Facet Rasch analysis before assignment and work measures were compared — related
- CTT-based quiz difficulty rankings are validated by IRT analysis with near-perfect rank correlation — related
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
ctt-mfrm-difficulty-indices-perfect-correlation-open-ended |
title |
CTT and MFRM yield a positive, perfect correlation between item difficulty indices for open-ended items under a crossed design |
description |
CTT and MFRM yield a positive, perfect correlation between item difficulty indices for open-ended items under a crossed design |
status |
review |
evidence_strength |
moderate |
newest_evidence |
2018 |
recheck_by |
2021 |
generated |
by process:wiki-ingest on 2026-09-27 |
trust |
unverified — no one has confirmed this page's content |
sources |
1 — ilhan-2018 |
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