Randomization tests for single-case experiments: State of the art, state of the science, and state of the application

• A single-case experiment can be used to evaluate the effect of an intervention for a single entity.
• Schedules to include randomization into the design of single-case experiments are discussed.
• The use of a free software package is illustrated.

A single-case experimental design is a research design that can be used to evaluate the effect of an intervention for a single entity. There are two important schedules to include randomization into the design of single-case experiments: phase designs and alternation designs. We present these two schedules and provide a detailed example for each schedule. For both examples, we illustrate the use of a free software package that assists researchers in designing and analyzing single-case experiments using randomization tests. Furthermore, we discuss several additions (simultaneous and sequential replication designs; meta-analysis of single-case experimental studies) and alternatives (statistical and visual analysis methods).