Korean J Med Educ.  2007 Jun;19(2):163-169.

Testing Unidimensionality and Goodness-of-fitness for the Application of Item Response Theory to the Korean Medical Licensing Examination

• Yim MK
• Huh S

Abstract

PURPOSE: In order to apply the item response theory to test results, the assumptions made about unidimensionality and item goodness-of-fitness should be tested before analysis. To know if the Korean Medical Licensing Examination results fulfill these assumptions, appropriate tests were done on these two features.
METHODS
Three results(from three subjects) of the Korean Medical Licensing Examination, done in January 2004, were converted into 1, 0 data. The Holland and Rosenbaum Method(HRMH) and DETECT were used to test unidimensionality. The Winsteps was used to test goodness-of-fitness according to the Rasch model.
RESULTS
Unidimensionality was rejected by HRMH but accepted by DETECT. With the Rasch model, 2 out of 550 items were inadequate. Each 137, 73 and 455 examinees out of 3,881 were inadequate in three subjects of 126, 400 and 24 items.
CONCLUSION
The above results suggest that DETECT is desirable for testing unidimensionality of high-stakes tests with more than 100 items. According to the Rasch model, the Korean Medical Licensing Examination fulfills the goodness-of-fitness to be analyzed according to the item response theory.

Keyword

Item response theory; Unidimensionality; Goodness-of-fitness; Korean Medical Licensing Examination

MeSH Terms

Licensure*
Netherlands