The What Works Clearinghouse quality standards provide guidance regarding studies capable of supporting evidence-based practices. Standards concerning single-case designs have been extensively revised to accommodate new evaluation methods, such as the design comparable effect size. These designs often omit data in which children and other participants receive training. Recently, the What Works Clearinghouse suggested studies with such “empty training phases” do not meet minimum standards of evidence. However, evidence regarding the effect of empty training phases on results is limited. This study used a subset of single-case design data from a recent meta-analysis to simulate studies with empty training phases. We calculated design-comparable effect sizes, evaluated differences between simulated and unsimulated data, and conducted random effects meta-analyses. Effects of simulated studies with artificially designed empty training phases were nearly four times as large as effects of the original, unaltered data. Guidance for intervention researchers follows a description of findings.

中文翻译：

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What Works Clearinghouse 指南对单例设计的影响：空训练阶段的调查


What Works Clearinghouse 质量标准为能够支持循证实践的研究提供指导。有关单案例设计的标准已被广泛修订，以适应新的评价方法，例如设计可比效应大小。这些设计通常省略了儿童和其他参与者接受培训的数据。最近，What Works Clearinghouse 建议具有这种 “空训练阶段 ”的研究不符合最低证据标准。然而，关于空训练阶段对结果影响的证据是有限的。这项研究使用了来自最近一项荟萃分析的单案例设计数据的子集来模拟具有空训练阶段的研究。我们计算了设计可比的效应大小，评估了模拟和非模拟数据之间的差异，并进行了随机效应meta分析。具有人工设计的空训练阶段的模拟研究的效果几乎是原始、未改变数据效果的四倍。干预研究人员指南遵循对结果的描述。