Sample Size Determination In The Dif Tests Based On Partial Credit Model

In the filed of educational and psychological tests,test has been widely applied to the entrance,employment and social services,promotions,etc.,affects people's work and life.The fairness of test questions on differential subjects from the same overall group is differential item functioning(DIF)gets more and more attention of the public,and the sample size is the most important factor to influence the differential item functioning,and economic factors,selecting the appropriate sample size becomes very important.This paper studies the polytomous scored Partial Credit Model(PCM),the probability of the Type?error can be controlled at a predetermined level by basing the test on the appropriate number of respondents,to eliminate the influence of differential item functioning to respondents.Some simulation studies are conductted to show the performance of our methods.Finally,a real data analysis is provided to illustrate the implementation of the theoretical result..