Detecting Item Bias in an Anatomy & Physiology Test for Nursing Students using Item Response Theory

This study aimed to assess whether or not there were bias items towards male or female examinees in the Anatomy & Physiology (A&P) test for the Diploma of Nursing in Ministry of Health (MOH), Malaysia. The study involved 971 examinees from the first semester cohort of the January 2013 session in which 867 examinees were females and 104 males. A differential item functioning (DIF) analysis was conducted with the help of Xcalibre software using Mantel-Haenszel coefficient (M-H) method. While 88.9% of the items did not indicate bias, three items were found to demonstrate bias, namely Item 17 (M-H = 0.28, p < 0.05), 18 (M-H = 0.51, p < 0.05), and 29 (M-H = 0.54, p < 0.05), from the topics of Cardiovascular System and Digestive System. All these three items favour female examinees where by female examinees tend to answer it correctly as compared to male students. These items need to be further revised, so that decisions can be made whether to improve or to remove them from the test.