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Journal of Medical Education

Abstract

Background: Item analysis is used to ensure the validity of a test. The Classic Test Theory (CTT) and the Item Response Theory (IRT) are two main item analysis theories. Objective: This study discussed and compared advantages and disadvantages of CTT and IRT in screening out potential problematic test items. Expert opinion and student feedback were also considered before removal of truly problematic items. The study aimed to develop an item analysis procedure to ensure classroom test validity. Method: Eighty-six sixth-year medical students answered a newly developed authentic medical test composed of 48 multiple-choice questions. For item analysis, this study used CTT and IRT methods for the quantitative analysis, while the expert opinion and student feedback were used for the qualitative ones. Cronbach's Alphas were the coefficients of the internal consistency of the whole test. Results: The Cronbach's Alpha of the responses to all 48 items in the test was 0.55. Using IRT, 4 items were deleted and the alpha increased to 0.57. Using CTT, 24 items were deleted and the alpha increased to 0.70. Using IRT and CTT as well as expert opinion, 21 items were deleted and the alpha increased to 0.71. Conclusions: Both CTT and IRT help to increase the test reliability. Compared to IRT, CTT is more effective at increasing the test reliability. Moreover, expert opinion and student feedback offer valuable suggestions for item selection. Based on CTT, expert opinion and student feedback is a considerable procedure for item selection.

First Page

12

Last Page

20

DOI

10.6145/jme201302

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