A systematic literature review of randomization procedures within single-case research designs

This systematic literature review examined the use of randomization procedures within single-case research designs in the field of education. We identified 717 documents that met our inclusion criteria for reports (articles, dissertations, theses) published or made available between 2010 and 2022. Results indicated a steady increase in the use of randomization procedures over this twelve-year period. Researchers most often included randomization procedures within multiple baseline and alternating treatments designs. The most common types of randomization procedures in order from most to least often reported were within-intervention case randomization, phase-order randomization, between-intervention case randomization, and intervention start-point randomization. In addition, randomization tests were conducted in 8% of studies. Findings of this study provide implications for research when using and reporting randomization procedures. Suggestions for determining suitable student outcomes and educational settings for using randomization procedures within single-case research are discussed.