Getting the MOST out of Single-Case Experimental Intervention Development: An Application of the Multiphase Optimization STrategy

As behavioral science moves towards more equitable and individualized interventions, there is a pressing need for flexible and efficient research frameworks. The Multiphase Optimization STrategy (MOST) is a framework for developing more optimized interventions through a sequential development of screening, refining, and confirming phases of knowledge generation. Traditionally reliant on group design studies, MOST can be strengthened by leveraging the strengths of single-case experimental design (SCED) studies, which allow for real-time modifications, contextual sensitivity, and individualized analysis. In this paper, we provide guidance that enables SCED researchers to leverage the benefits of the MOST framework to enhance adaptive intervention development, particularly for, but not limited to, populations that are often underrepresented in group design research. By doing so, researchers can more effectively identify, optimize, and evaluate adaptive intervention components to accelerate the development of evidence-based practice and build equitable behavioral health interventions.