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Threats To Internal Validity In Multiple-Baseline Design Variations, Timothy A. Slocum, Sarah E. Pinkelman, P. Raymond Joslyn, Beverly Nichols

Special Education and Rehabilitation Counseling Faculty Publications

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 vigor 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 …