Determination of differantial item functioning (DIF) according to SIBTEST, Lord’s χ2 , Raju’s area measurement and Breslow-Day methods

Abstract

The aim of this study is to examine whether the items in the mathematics subtest of the Centralized High School Entrance Placement Test [HSEPT] administered in 2012 by the Ministry of National Education in Turkey show DIF according to gender and type of school. For this purpose, SIBTEST, Breslow-Day, Lord’s χ2 and Raju's area measurement methods were used to determine the DIF of the 20 items in the mathematics subtest of HSEPT in 2012, and it was determined whether the items show DIF according to these methods or not. The research was conducted on the basis of the data obtained from HSEPT that the eighth grade students took in 2012. After the missing data were removed from the data set, DIF analyses were performed for the mathematics subtest of 1,063,570 (nfemale=523,939 and nmale=539,631; nstate school=1,025,979 and nprivate school =37,591) in total. Since it is aimed to examine the current situation, this study is based on a descriptive research design. According to the methods used, the number and DIF levels of the items with DIF differed depending on the variables of gender and type of school. In line with the findings, this research suggests the researchers to use at least two methods to determine the DIF.

Keywords

• Differential item functioning
• SIBTEST
• Breslow-Day
• Lord’s χ2
• Raju’s Area Measurement