Lanovaz Marc J, Turgeon Stéphanie
École de psychoéducation, Université de Montréal, C.P. 6128, succursale Centre-Ville, Montreal, QC H3C 3J7 Canada.
Centre de recherche de l'Institut universitaire en santé mentale de Montréal, Montreal, QC Canada.
Perspect Behav Sci. 2020 Jul 29;43(3):605-616. doi: 10.1007/s40614-020-00263-x. eCollection 2020 Sep.
Design quality guidelines typically recommend that multiple baseline designs include at least three demonstrations of effects. Despite its widespread adoption, this recommendation does not appear grounded in empirical evidence. The main purpose of our study was to address this issue by assessing Type I error rate and power in multiple baseline designs. First, we generated 10,000 multiple baseline graphs, applied the dual-criteria method to each tier, and computed Type I error rate and power for different number of tiers showing a clear change. Second, two raters categorized the tiers for 300 multiple baseline graphs to replicate our analyses using visual inspection. When multiple baseline designs had at least three tiers and two or more of these tiers showed a clear change, the Type I error rate remained adequate (< .05) while power also reached acceptable levels (> .80). In contrast, requiring all tiers to show a clear change resulted in overly stringent conclusions (i.e., unacceptably low power). Therefore, our results suggest that researchers and practitioners should carefully consider limitations in power when requiring all tiers of a multiple baseline design to show a clear change in their analyses.
设计质量指南通常建议，多重基线设计应至少包含三次效果展示。尽管这一建议被广泛采用，但其似乎并非基于实证证据。我们研究的主要目的是通过评估多重基线设计中的I型错误率和检验效能来解决这一问题。首先，我们生成了10000个多重基线图表，对每一层应用双标准方法，并计算不同层数（显示出明显变化）的I型错误率和检验效能。其次，两名评分者对300个多重基线图表的各层进行分类，以便通过目视检查重复我们的分析。当多重基线设计至少有三层，且其中两层或更多层显示出明显变化时，I型错误率仍保持在可接受水平（<0.05），同时检验效能也达到了可接受水平（>.80）。相比之下，要求所有层都显示出明显变化会导致结论过于严格（即检验效能低得不可接受）。因此，我们的结果表明，研究人员和从业者在要求多重基线设计的所有层在分析中都显示出明显变化时，应仔细考虑检验效能的局限性。
