Parameters for the Item Response Theory between Different Groups —— An Example of Comparison of the Mathematics Placement Tests between Two Universities ——
43 , 2016-02 , 広島工業大学
The item response theory (IRT) is often used in modern educational evaluation scene. However, if the two groups are different from each other, the estimated IRT parameters such as item difficulty parameters, discriminant parameters, and students’ ability parameters in each group may differ from each other. We have investigated this phenomenon using the two universities’ testing results (high school level mathematics placement tests). The universities are both specified to science and technology. The number of students in investigation in a university is 145, and 179 in another university. As a result, we have found that 1) the estimates for the item difficulty parameters show no clear differences between the two groups, 2) the estimates for the students’ ability parameters differ from each other if the two groups are different. To compare the difference of ability among groups, use of combined data is strongly required.