Examining and Enhancing the Methodological Quality of Nonconcurrent Multiple-Baseline Designs

In this article we respond to the recent recommendation of Slocum et al. (2022), who provided conceptual and methodological recommendations for reconsidering the credibility and validity of the nonconcurrent multiple-baseline design. We build on these recommendations and offer replication and randomization upgrades that should further improve the status of the nonconcurrent version of the design in standards and single-case design research. Although we suggest that the nonconcurrent version should be an acceptable methodological option for single-case design researchers, the traditional concurrent multiple-baseline design should generally be the design of choice.