The Exploration And Research Of Parametric Polytomous Differential Item Functioning Detection Method

This dissertation includes two sections of theory survey and application study mainly. Theory survey part introduces some concepts relative to Item Bias and Differential Item Functioning, as well as the recent development and some ordinary methods, especially parametric IRT approaches used to explore DIE Based on the response the 21 optional item of the laws pertaining to the economy (both dichotomously and polytomously scored items) in 2004 intermediate economic test throughout country, a parametric procedures using the Graded Response Model (GRM, Samejima, 1969) and MULTILOG (Thissen,1991) was used to detect gender-related DIF, nation-related DIF, district-related DIF and work classification-related DIF. The parametric procedures research found: 4 items showed nation-related DIF; 1 item showed gender-related DIF; and only 1 item showed work classification-related DIF. Nation-related DIF (item 68) is a uniform DIF and item 64 appears both nation-related DIF and work classification-related DIF. According to the results of analysis among item statistics, characteristic curves and decisions of specialists, results show that the main cause of DIF are as follows: the economic development between districts, the working experiences, psychological traits between different groups, the interest or familiarity to the content, etc. Among the DIF, some are the benign.