Examining TEOG mathematic sub-test exam in terms of differential item functioning based on geographical regions

TEOG, known as the Secondary Education Transition System from Elementary Education is the central exam implemented from 2013-2014 to 2017-2018 academic years. The validity and reliability of a large-scale test, carried out throughout the country and intended for placement, must be high. Since Differential item functioning analysis (DIF) is a systematic fault, for validity and reliability, the test items must be free of DIF. In this study, through DM and SIBTEST methods, DIF was implemented on TEOG mathematics subtest of the fall and spring semesters of 2015-2016 according to the geographical area and independent of the statistical analysis results, the experts were asked whether the items contained DIF. According to statistical results of the study, the test items did not have DIF substantially. Only one item of the spring semester showed moderate DIF in the four regions compared to the Southeast Anatolian Region according to a single method. However, it was concluded that the test items did not contain DIF because it is determined by only one method. Moreover, it was observed that some experts gave inconsistent opinions with the analysis results on whether some items contained DIF. As a result of the study, it can be said that the reason for not observing the substance containing DIF according to the geographical regions in the TEOG mathematics subtest is due to the fact that the mathematics course has a structure which is at the lowest level from culture to culture or person to person and logical rules in itself