A single-subject design, which is also known as a single-case research design, provides a rigorous approach for documenting experimental effects. Single-case research has been used to (a) establish basic principles of behavior, (b) document the impact of specific interventions, and more recently (c) establish evidence-based practices. The defining feature of single-case research is the use of each participant (subject) as his or her own experimental control. This approach to research design arose from early work of researchers such as Burrhus F. Skinner and Werner Honig in the 1940s and 1950s focusing on behavior analysis, and it was codified in the seminal book Tactics of Scientific Research by Murray Sidman in 1960. Sidman defined in detail how the systematic study of individual participants over time could ...