Huang Hung-Yu
Psychol Rep. 2014 Feb;114(1):104-25. doi: 10.2466/03.PR0.114k11w0.
This study compares three methods of detecting differentialitem functioning (DIF), the equal mean difficulty (EMD), all-other-item (AOI), and constant item (CI) methods, in terms of estimation bias and rank order change of ability estimates using a series of simulations and two empirical examples. The CI method generated accurate DIF parameter estimates, whereas the EMD and AOI methods produced biased estimates. Moreover, as the percentage of DIF items in a test increased, the superiority of the CI method over the EMD and AOI methods became more apparent. The superiority of the CI method is independent of the sample size, test length, and item type (dichotomous or polytomous). Two empirical examples, a mathematics test and a hostility questionnaire, demonstrated that these three methods yielded inconsistent DIF detections and produced different ability estimate rankings.
本研究通过一系列模拟及两个实证示例，就估计偏差和能力估计的排序变化方面，比较了检测差异项目功能（DIF）的三种方法，即等平均难度（EMD）法、所有其他项目（AOI）法和常数项目（CI）法。CI法产生了准确的DIF参数估计值，而EMD法和AOI法产生了有偏差的估计值。此外，随着测试中DIF项目的百分比增加，CI法相对于EMD法和AOI法的优势变得更加明显。CI法的优势与样本量、测试长度和项目类型（二分制或多分制）无关。两个实证示例，一个数学测试和一个敌意问卷，表明这三种方法产生了不一致的DIF检测结果，并产生了不同的能力估计排名。
