Likelihood-Ratio DIF Testing: Effects of Nonnormality  

Oleh:

Woods, Carol M.

Jenis: Article from Journal - ilmiah internasional
Dalam koleksi: Applied Psychological Measurement vol. 32 no. 7 (Oct. 2008), page 511-526.
Topik: differential item functioning; LR-DIF; IRT-LR-DIF; item response theory; item bias; measurement invariance
Fulltext: 511.pdf (165.87KB)

Isi artikel

Differential item functioning (DIF) occurs when an itemhas different measurement properties for members of one group versus another. Likelihoodratio (LR) tests for DIF based on item response theory (IRT) involve statistically comparing IRT models that vary with respect to their constraints. A simulation study evaluated how violation of the normality assumption about the random latent variable for one or both groups affected IRT-LRDIF results. Item response data with or without DIF were generated from the two-parameter logistic model and fitted under the assumption that the latent distribution was normal for both groups. Although the IRT-LR-DIF method performed well when latent distributions were normal for both groups, results were distorted when the distribution was skewed for one or both groups. Specifically, Type I error was inflated, differences between reference- and focal-group item parameter estimates were inaccurate, and group differences in the mean and variance of the latent distribution were overestimated.

Opini Anda

Klik untuk menuliskan opini Anda tentang koleksi ini!

Kembali