Slocum Timothy A, Pinkelman Sarah E, Joslyn P Raymond, Nichols Beverly
Department of Special Education & Rehabilitation Counseling, Utah State University, 2865 Old Main Hill, Logan, UT 84322 USA.
Perspect Behav Sci. 2022 Jan 27;45(3):619-638. doi: 10.1007/s40614-022-00326-1. eCollection 2022 Sep.
Multiple baseline designs-both concurrent and nonconcurrent-are the predominant experimental design in modern applied behavior analytic research and are increasingly employed in other disciplines. In the past, there was significant controversy regarding the relative rigor of concurrent and nonconcurrent multiple baseline designs. The consensus in recent textbooks and methodological papers is that nonconcurrent designs are less rigorous than concurrent designs because of their presumed limited ability to address the threat of coincidental events (i.e., history). This skepticism of nonconcurrent designs stems from an emphasis on the importance of across-tier comparisons and relatively low importance placed on replicated within-tier comparisons for addressing threats to internal validity and establishing experimental control. In this article, we argue that the primary reliance on across-tier comparisons and the resulting deprecation of nonconcurrent designs are not well-justified. In this article, we first define multiple baseline designs, describe common threats to internal validity, and delineate the two bases for controlling these threats. Second, we briefly summarize historical methodological writing and current textbook treatment of these designs. Third, we explore how concurrent and nonconcurrent multiple baselines address each of the main threats to internal validity. Finally, we make recommendations for more rigorous use, reporting, and evaluation of multiple baseline designs.
多重基线设计——包括同时性和非同时性的——是现代应用行为分析研究中的主要实验设计，并且在其他学科中也越来越多地被采用。过去，关于同时性和非同时性多重基线设计的相对严谨性存在重大争议。最近的教科书和方法学论文中的共识是，非同时性设计不如同时性设计严谨，因为它们假定应对巧合事件（即历史因素）威胁的能力有限。对非同时性设计的这种怀疑源于对跨层级比较重要性的强调，以及对为解决内部效度威胁和建立实验控制而进行的重复层级内比较的相对较低重视。在本文中，我们认为主要依赖跨层级比较以及由此导致的对非同时性设计的贬低是没有充分理由的。在本文中，我们首先定义多重基线设计，描述内部效度的常见威胁，并阐述控制这些威胁的两个基础。其次，我们简要总结这些设计的历史方法学著作和当前教科书的论述。第三，我们探讨同时性和非同时性多重基线如何应对内部效度的每一个主要威胁。最后，我们对更严谨地使用、报告和评估多重基线设计提出建议。
