The impact of differential item functioning on ability estimation using the Korean Medical Licensing Examination with computerized adaptive testing: a post-hoc simulation study.

Purpose: This study examined the impact of differential item functioning (DIF) on ability estimation in a computerized adaptive testing (CAT) environment using real response data from the 2017 Korean Medical Licensing Examination (KMLE). We hypothesized that excluding gender-based DIF items would im...

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Publicado en:Journal of Educational Evaluation for Health Professions Vol. 22; pp. 1 - 9
Autores principales: Kim, Dogyeong, Choi, Jeongwook, Seo, Dong Gi
Formato: equations & formulas pictorial research tables/charts Journal Article
Publicado: National Health Personnel Licensing Examination Board 2025
Acceso en línea:Ver este registro en EBSCOhost
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      dt: 2025
      vid: 22
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      pub: National Health Personnel Licensing Examination Board
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        10.3352/jeehp.2025.22.31
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        atl: The impact of differential item functioning on ability estimation using the Korean Medical Licensing Examination with computerized adaptive testing: a post-hoc simulation study.
      aug:
        au:
          Kim, Dogyeong
          Choi, Jeongwook
          Seo, Dong Gi
        affil: Department of Psychology, College of Social Science, Hallym University, Chuncheon, Korea
      sug:
        subj:
          Education, Medical South Korea
          Credentialing Examinations
          Licensure
          Educational Measurement
          Computerized Educational Testing
          Differential Item Functioning
          Psychometrics Evaluation
          Human
          Funding Source
          South Korea
          Male
          Female
          Post Hoc Analysis
          Simulations
          Sex Factors
          Discrimination
          Validity Evaluation
          Descriptive Statistics
          Pearson's Correlation Coefficient
          Rasch Analysis
          Data Analysis Software
          Male
          Female
      ab: Purpose: This study examined the impact of differential item functioning (DIF) on ability estimation in a computerized adaptive testing (CAT) environment using real response data from the 2017 Korean Medical Licensing Examination (KMLE). We hypothesized that excluding gender-based DIF items would improve estimation accuracy, particularly for examinees at the extremes of the ability scale. Methods: The study was conducted in 2 steps: (1) DIF detection and (2) post-hoc simulation. The analysis used data from 3,259 examinees who completed all 360 dichotomous items. Gender-based DIF was detected with the residual-based DIF method (reference group: males; focal group: females). Two CAT conditions (all items vs. DIF-excluded) were compared against a "true θ" estimated from a fixed-form test of 264 non-DIF items. Accuracy was evaluated using bias, root mean square error (RMSE), and correlation with true θ. Results: In the CAT condition excluding DIF items, accuracy improved, with RMSE reduced and correlation with true θ increased. However, bias was slightly larger in magnitude. Gender-specific analyses showed that DIF removal reduced the underestimation of female ability but increased the underestimation of male ability, yielding estimates that were fairer across genders. When DIF items were included, estimation errors were more pronounced at both low and high ability levels. Conclusion: Managing DIF in CAT-based high-stakes examinations can enhance fairness and precision. Using real examinee data, this study provides practical evidence of the implications of DIF for CAT-based measurement and supports fairness-oriented test design.
      pubtype: Academic Journal
      doctype:
        equations & formulas
        pictorial
        research
        tables/charts
        Journal Article
      ougenre: Article
    language: English
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