An Analytic Comparison of Effect Sizes for Differential Item Functioning
An Analytic Comparison of Effect Sizes for Differential Item Functioning
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差异项目功能效应大小的分析比较
DOI：
10.1080/08957347.2011.580255
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发表时间：
2011
影响因子：
1.5
通讯作者：
Christine E. DeMars
中科院分区：
文献类型：
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作者：
Christine E. DeMars
本文描述了DIF的三种效应大小：对数优势比(对数赔率差异)、概率正确差异和解释方差的比例。使用这些指数涉及到以不同方式概念化DIF的程度。这篇综合综述讨论了试题难度、试题辨别和试题下渐近线如何以不同的方式影响这些测量。例如，对于固定的辨别，概率的差异随着项目难度和平均能力之间的差异的增加而减小。在相同条件下，如果下渐近线为零，则赔率比的对数保持不变。对于简单题和难题，非零下渐近线对称地减小了概率差的绝对值，但对于难题，它使对数赔率差的绝对值减小得更多。因此，人们不能在一个指标中设置定义大效果大小的标准，而在另一个指标中找到在所有项目或能力分布上相等的对应标准。在选择效果大小时，必须了解和考虑这些差异。
Three types of effects sizes for DIF are described in this exposition: log of the odds-ratio (differences in log-odds), differences in probability-correct, and proportion of variance accounted for. Using these indices involves conceptualizing the degree of DIF in different ways. This integrative review discusses how these measures are impacted in different ways by item difficulty, item discrimination, and item lower asymptote. For example, for a fixed discrimination, the difference in probabilities decreases as the difference between the item difficulty and the mean ability increases. Under the same conditions, the log of the odds-ratio remains constant if the lower asymptote is zero. A non-zero lower asymptote decreases the absolute value of the probability difference symmetrically for easy and hard items, but it decreases the absolute value of the log-odds difference much more for difficult items. Thus, one cannot set a criterion for defining a large effect size in one metric and find a corresponding criterion in another metric that is equivalent across all items or ability distributions. In choosing an effect size, these differences must be understood and considered.