ABSTRACT
X type questions have been used for the national medical licensing examination since 1997. At Tsukuba University, X type questions have been used since 1996. We compared X typeand K type questions on the basis of the percentage of correct answers and discrimination power. The average percentage of correct answers was 68.2% for K type questions and 53.1% for X type questions. However, the average discrimination power was +0.227 for K type questions and +0.257 for X type questions. These results indicate that X type questions are more difficult and are suitable for achievement tests. The estimated knowledge quantity was 2.04 for K type questions and 2.32 for X type questions. This suggests that the person writing the questions decreased the essential difficulty of X type questions.