Rasch 모형하에서 공통 능력척도 개발을 위한 적률 및 특성곡선 척도연계 방법들의 기능 비교

초록

In the development of common ability scales using item response theory (IRT), the Rasch scale that is defined by setting the mean difficulty of items at 0 should be distinguished from the “0-1” scale that is defined by standardizing the ability distribution of examinees. The linking between two Rasch ability scales requires adjustments only for the origin difference between them, but the linking between two “0-1” ability scales calls for adjustments for both of the origin and unit differences. The purpose of the present study is to present modified versions of the “0-1” scales based moment and characteristic curve linking methods that can be used for linking the Rasch ability scales and to investigate the relative performances of the modified linking methods. In addition, this study provides how to properly implement the “0-1” scales based linking methods in order that IRT parameter estimates expressed on “0-1” ability scales may be transformed onto the Rasch ability scale. Results from a simulation study showed that under the Rasch modeling and calibration, the modified linking methods performed slightly better than or nearly as well as the linking methods developed based on “0-1” scales.

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