THE COMPARISION RESEARCH OF TWO MODIFIED ITEM-SELECTED METHODS IN CAT

Item-selecting method of maximum information is widely used in CAT. But it inclines to select the item of high differentiation, hence brings about high percentage of exposure and low percentage for using item base. A-stratification method can overcome this, but it has its faults. The paper introduces two modified item-selecting methods based on a-stratification item-selecting. On the basis of analyzing the two kinds of methods, the paper compares them by monte-karlo simulation experiment.