Battauz Michela
Department of Economics and Statistics, University of Udine, Udine, Italy.
Psychometrika. 2016 Oct 3. doi: 10.1007/s11336-016-9517-x.
When test forms are calibrated separately, item response theory parameters are not comparable because they are expressed on different measurement scales. The equating process includes the conversion of item parameter estimates on a common scale and the determination of comparable test scores. Various statistical methods have been proposed to perform equating between two test forms. This paper provides a generalization to multiple test forms of the mean-geometric mean, the mean-mean, the Haebara, and the Stocking-Lord methods. The proposed methods estimate simultaneously the equating coefficients that permit the scale transformation of the parameters of all forms to the scale of the base form. Asymptotic standard errors of the equating coefficients are derived. A simulation study is presented to illustrate the performance of the methods.
当分别校准测试形式时，项目反应理论参数不可比，因为它们是在不同的测量尺度上表示的。等值化过程包括将项目参数估计值转换到一个共同的尺度上，并确定可比的测试分数。已经提出了各种统计方法来在两种测试形式之间进行等值化。本文将均值 - 几何均值法、均值 - 均值法、Haebara法和Stocking - Lord法推广到多种测试形式。所提出的方法同时估计等值化系数，这些系数允许将所有形式的参数尺度转换为基础形式的尺度。推导了等值化系数的渐近标准误差。进行了一项模拟研究以说明这些方法的性能。
