Many universities stress gradually the importance of english-medium class in order to improve the international competitiveness and the internationalization of the university. In this paper, we compare english-medium class with korean class using course evaluation score. Also we analyze the factors that affect the effectiveness of the course evaluation score of english-medium class. First, logistic regression analysis is used to examine the main effects of subjects and individual characteristics. Also, decision tree analysis is used to examine the interaction effects for subjects and individual characteristics. The results of this paper are as follows. Grade, department category, class size, GPA and screening method affect the effectiveness of english-medium class. The highest effectiveness group of english-medium class is that grade is freshmen and department category is humanity. Also the group of the second highest effectiveness group is that grade is freshmen and department category is nature and art and GPA is high.