TitleDetecting DIF between Conventional and Computerized Adaptive Testing: A Monte Carlo Study
Publication TypeConference Paper
Year of Publication2011
AuthorsRiley, BB, Carle, AC
Conference NameAnnual Conference of the International Association for Computerized Adaptive Testing
Date Published10/2011
Keywords95% Credible Interval, CAT, DIF, differential item function, modified robust Z statistic, Monte Carlo methodologies

A comparison od two procedures, Modified Robust Z and 95% Credible Interval, were compared in a Monte Carlo study. Both procedures evidenced adequate control of false positive DIF results.

  • Exception: low difficulty items (< -2.5 logits).
  • Not significantly affected by % of DIF items.
  • Was affected by mean trait level difference.
  • 95% Credibility Interval evidenced slightly higher power to detect DIF, but also higher false positive rate.