A Study On The LDFA Method And Its Application In The Analysis Of DIF

With the problem of fairness in psychological and educational testing drawing an increasing attention world-widely, the study of DIF has been one of the hottest topic in psychological and educational domain.This thesis generalized the recent study of DIF in-and-out China, and gave a systematical introduction about LDFA method and a brief comparison between it and several other polytomously scored DIF detecting methods. After conducted a simulation study of LDFA method to test its validity, this thesis made an applicational research on analyzing DIF of an English Test in the College Entrance Examination with LDFA method.The study of LDFA method in a 300-times simulation research showed that LDFA method can be used both in 0,1 scored and polytomously scored items, and it can detect both uniform DIF and Nonuniform DIF simultaneously in one model. It also showed that the indexs of statistical power and the type I error of LDFA method are 0.9 and 0.04 respectively. The LDFA method was used to detect DIF in the English test from four aspects-- male or female, arts or science, city or country and the Han or the minority, and find three, five, and four items containing DIF respectively.