The Nonconcurrent Multiple-Baseline Design: It is What it is and Not Something Else

[...]their conceptual analysis probes the underlying logic of multiple-baseline designs and their inherent temporal structure that has been considered a critical element in efforts to establish experimental control. In their book on group comparison logic, they focused on how specific design tactics did/did not control for exogenous threats to internal validity. Because the Slocum et al. article focused on three of Campbell and Stanley’s threats to internal validity (i.e., maturation, test–retest, and history), I will focus my commentary on those specific confounding variables (plus one additional confounding variable). Given that most maturational variables unfold over the developmental course of the individual, they tend to be gradual (cf. [...]as long as the multiple-baseline design is relatively brief in time scope (e.g., days or weeks), developmental threats to experimental control may not be a concern. [...]kudos to Slocum et al. for expanding the discussion of nonconcurrent multiple-baseline designs.