Differential item/test functioning, gender-related DIF/DTF, item/test bias, university entrance exam, national entrance exam

The performance measurement of examinees through exerting statistical control on their ability may reveal different results in different gender groups. In this case, gender-related differential item functioning and differential test functioning as well as item/test bias is likely to occur. The main purpose of this research was to investigate the gender-related DIF/DTF and gender-related bias throughout national entrance exams in Iran. Then, special tests of a test booklet in 5 experimental groups participating in national entrance exams were chosen from 2008 to 2011 through one-stage cluster sampling method. Next, logistic regression and item response theory were used to investigate DIF and DTF, respectively. The results showed that, on average, about 14% of investigated test items had gender-related DIF with negligible effect size (EF