Three multidimensional IRT models for testlet-based tests¶
Research Method · All research methods
Evidence · 2 claims (2 for) · 1 study (1 theoretical),q2· 0 of 1 report an effect size · 2 claims rest on one study
Description¶
The report describes three multidimensional IRT models that account for conditional dependence among items sharing a testlet stimulus by incorporating testlet-specific dimensions. In the bifactor model, "each item measures a general dimension in addition to a testlet-specific dimension." The testlet model constrains specific loadings to be proportional to general loadings within each testlet, and in the second-order model items load only on testlet-specific factors whose correlations are modeled through a second-order factor. The report shows the latter two are formally equivalent and can be formulated as restricted bifactor models, and estimates all three within a common full-information ma
Accounts¶
- Three multidimensional IRT models for testlet-based tests: bifactor, testlet, and second-order models: The report describes three multidimensional IRT models that account for conditional dependence among items sharing a testlet stimulus by incorporating testlet-specific dimensions. In the bifactor model, "each item measures a general dimension in addition to a testlet-specific dimension." The testlet model constrains specific loadings to be proportional to general loadings within each testlet, and in the second-order model items load only on testlet-specific factors whose correlations are modeled through a second-order factor. The report shows the latter two are formally equivalent and can be formulated as restricted bifactor models, and estimates all three within a common full-information ma (Rijmen (2009))
Claims¶
- The second-order multidimensional IRT model for testlets is formally equivalent to the testlet model, and both are restricted bifactor models [+M]
- In an empirical comparison on a testlet-based English assessment test, the bifactor model is preferred over the second-order and unidimensional 2PL models by both AIC and BIC [+M]
Related Research Methods¶
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Key Sources¶
- Rijmen, F. (2009). Three Multidimensional Models for Testlet-Based Tests: Formal Relations and an Empirical Comparison. ETS Research Report RR-09-37. http://www.ets.org/research/contact.html. doi:10.1002/j.2333-8504.2009.tb02194.x
Page metadata
| Field | Value |
|---|---|
type |
research-method |
id |
three-multidimensional-irt-models-for-testlet-based-tests |
title |
Three multidimensional IRT models for testlet-based tests |
description |
The report describes three multidimensional IRT models that account for conditional dependence among items sharing a testlet stimulus by incorporating testlet-specific dimensions. |
status |
review |
moved_from |
theory/multidimensional-irt-models-testlet-based-tests |
generated |
by process:sweep-kinds on 2026-10-10 |
trust |
unverified — no one has confirmed this page's content |
sources |
1 — rijmen-2009 |
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