Department of Surgery, University of Queensland Medical School, Princess Alexandra Hospital, Brisbane, Australia.
Arch Clin Neuropsychol. 2011 Feb;26(1):67-75. doi: 10.1093/arclin/acq087. Epub 2010 Dec 8.
There is an ongoing debate over the preferred method(s) for determining the reliable change (RC) in individual scores over time. In the present paper, specificity comparisons of several classic and contemporary RC models were made using a real data set. This included a more detailed review of a new RC model recently proposed in this journal, that used the within-subjects standard deviation (WSD) as the error term. It was suggested that the RC(WSD) was more sensitive to change and theoretically superior. The current paper demonstrated that even in the presence of mean practice effects, false-positive rates were comparable across models when reliability was good and initial and retest variances were equivalent. However, when variances differed, discrepancies in classification across models became evident. Notably, the RC using the WSD provided unacceptably high false-positive rates in this setting. It was considered that the WSD was never intended for measuring change in this manner. The WSD actually combines systematic and error variance. The systematic variance comes from measurable between-treatment differences, commonly referred to as practice effect. It was further demonstrated that removal of the systematic variance and appropriate modification of the residual error term for the purpose of testing individual change yielded an error term already published and criticized in the literature. A consensus on the RC approach is needed. To that end, further comparison of models under varied conditions is encouraged.
关于确定个体分数随时间可靠变化（RC）的首选方法，一直存在争议。在本文中，使用真实数据集对几种经典和现代 RC 模型进行了特异性比较。这包括对最近在本期刊上提出的新 RC 模型的更详细回顾，该模型使用个体内标准差（WSD）作为误差项。该模型被认为对变化更敏感，在理论上更优越。本研究表明，即使存在均值练习效应，在可靠性良好且初始和重测方差相等的情况下，各模型的假阳性率也具有可比性。然而，当方差不同时，各模型之间的分类差异变得明显。值得注意的是，在这种情况下，使用 WSD 的 RC 提供了不可接受的高假阳性率。据认为，WSD 从未打算以这种方式测量变化。WSD 实际上结合了系统和误差方差。系统方差来自可测量的治疗间差异，通常称为练习效应。进一步证明，去除系统方差并适当修改残差误差项以测试个体变化，会得到一个已经发表并在文献中受到批评的误差项。需要就 RC 方法达成共识。为此，鼓励在不同条件下进一步比较模型。
