The MIMIC method with scale purification for detecting differential item functioning

Wen Chung WANG, Ching Lin SHIH, Chih Chien YANG

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36 Citations (Scopus)


This study implements a scale purification procedure onto the standard MIMIC method for differential item functioning (DIF) detection and assesses its performance through a series of simulations. It is found that the MIMIC method with scale purification (denoted as M-SP) outperforms the standard MIMIC method (denoted as M-ST) in controlling false-positive rates and yielding higher true-positive rates. Only when the DIF pattern is balanced between groups or when there is a small percentage of DIF items in the test does M-ST perform as appropriately as M-SP. Moreover, both methods yield a higher true-positive rate under the two-parameter logistic model than under the three-parameter model. M-SP is preferable to M-ST, because DIF patterns in real tests are unlikely to be perfectly balanced and the percentages of DIF items may not be small. Copyright © 2009 Sage Publications.
Original languageEnglish
Pages (from-to)713-731
JournalEducational and Psychological Measurement
Issue number5
Publication statusPublished - Oct 2009



Wang, W.-C., Shih, C.-L., & Yang, C.-C. (2009). The MIMIC method with scale purification for detecting differential item functioning. Educational and Psychological Measurement, 69(5), 713-731.


  • Differential item functioning
  • Scale purification
  • Item response theory
  • Confirmatory factor analysis