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ERIC Number: ED600180
Record Type: Non-Journal
Publication Date: 2017-May-30
Pages: 47
Abstractor: As Provided
ISBN: N/A
ISSN: EISSN-
EISSN: N/A
Available Date: N/A
Summed Score Likelihood Based Indices for Testing Latent Variable Distribution Fit in Item Response Theory
Li, Zhen; Cai, Li
Grantee Submission
In standard item response theory (IRT) applications, the latent variable is typically assumed to be normally distributed. If the normality assumption is violated, the item parameter estimates can become biased. Summed score likelihood based statistics may be useful for testing latent variable distribution fit. We develop Satorra-Bentler type (Satorra & Bentler, 1994) moment adjustments to approximate the test statistics' tail-area probability. A simulation study was conducted to examine the calibration and power of the unadjusted and adjusted statistics in various simulation conditions. Results show that the proposed indices have tail-area probabilities that can be closely approximated by central chi-squared random variables under the null hypothesis. Furthermore, the test statistics are focused. They are powerful for detecting latent variable distributional assumption violations, and not sensitive (correctly) to other forms of model misspecification such as multidimensionality. As a comparison, the goodness-of-fit statistic M2 (Maydeu-Olivares & Joe, 2005) has considerably lower power against latent variable non-normality than the proposed indices. Empirical data from a patient-reported health outcomes study is used as illustration.
Publication Type: Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: National Center for Education Research (ED)
Authoring Institution: N/A
IES Funded: Yes
Grant or Contract Numbers: R305D140046
Author Affiliations: N/A