ERIC Number: EJ723311
Record Type: Journal
Publication Date: 2006
Reference Count: 30
DIF Identification Using HGLM for Polytomous Items
Williams, Natasha J.; Beretvas, S. Natasha
Applied Psychological Measurement, v30 n1 p22-42 2006
The relationship between the hierarchical generalized linear model (HGLM) and item response theory (IRT) models has been demonstrated for dichotomous items. The current study demonstrated the use of the HGLM for polytomous items (termed PHGLM) for identification of differential item functioning (DIF). First, the algebraic equivalence between parameterizations of a constrained form of Muraki's rating scale model and PHGLM was demonstrated. Next, as a precursor to using the PHGLM for DIF identification, a simulation was conducted to compare estimation of item and person latent trait parameters using HLM 5 and PARSCALE software. The resulting PHGLM and IRT parameter estimates were comparable. Last, a simulation was conducted that compared the performance of PHGLM with that of the generalized Mantel-Haenszel statistic for DIF identification. Both approaches performed similarly. Benefits and limitations of using PHGLM for DIF identification are presented. Index terms: hierarchical linear modeling, item response theory, polytomous items, parameter estimation, differential item functioning, attitude measurement.
Descriptors: Identification, Rating Scales, Test Items, Item Response Theory, Test Bias, Simulation, Models
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Publication Type: Journal Articles; Reports - Evaluative
Education Level: N/A
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