Korean J Med Educ.  2001 May;13(1):159-167.

Correlation among Item Characteristics of Examinations in College of Medicine

• Huh S

Abstract

After item analysis of examinations in College of Medicine, the correlation among characteristics were examined for the better understanding of their meaning. The 78 subjected examinations in College of Medicine, Hallym University, Korea from March 1999 to October 2000 were analyzed. Discrimination indexes (D) by the method of extreme group were positively correlated with item-total correlation(ITC) with mean correlation coefficient r=0.8506 ranged between 0.6430 and 0.9520. Number of items of each examination was positively correlated with Cronbach coefficient alpha reliability index(r=0.7920) whereas negatively correlated with standard deviation(r=-0.5691), odd-even split reliability index(r=-0.8767) and mean ITC(r=-0.4079). Thereafter, the standard deviation was positively correlated with odd-even split reliability index (r=0.5072) and mean ITC(r=0.6166). There was negative correlation between Cronbach coefficient alpha reliability index and odd-even split reliability index(r=-0.7385). Above results suggested that the number of items in each examination was most powerful factor affecting to other item analysis characteristics. The appropriate number of items should be considered for better result of item analysis characteristics. Odd-even split reliability index is not appropriate for the estimation of the reliability among item, since it decreased according to the increase of number of items. Positive and high correlation between D and ITC means that both methods are appropriate to interpretate the discriminating power of the items.

Keyword

Item analysis; Evaluation; Discrimination index; Reliability index

MeSH Terms

Discrimination (Psychology)
Korea