Alternating Treatments Design

Alternating treatment designs, also called multielement designs, are single-case experimental designs, characterized by a rapid and frequent alternation of conditions. The specific sequence of conditions is usually determined at random, which enhances internal validity. This design feature makes possible the use of randomization tests, which improves statistical conclusion validity. Furthermore, replication of different alternation sequences across participants in the context of the same study is possible. In this entry, the main features of alternating treatment designs are described, distinguishing different ways of determining the alternation sequence and different uses. Indications for data analysis are also provided.