Abstract
The identification of interventions that are both effective and efficient is an ongoing need for the practice of applied behavior analysis. The parallel treatments design (PTD) has been described as powerful tool for comparing interventions in applied settings. The PTD combines elements of the multiple probe design and the adapted alternating treatments design. Execution of a PTD requires adherence to experimental tactics related to both designs, as well as adherence to specific features of the PTD outlined by the original authors (Gast & Wolery, 1988). The purpose of this systematic literature review was to evaluate (a) publication trends with the PTD, (b) applications of the PTD across behaviors and interventions, and (c) the extent to which articles that named the PTD as the design adhered to its defining features. Outcomes are discussed with respect to the utility of the PTD, limitations of the PTD, and potential refinements of the definition of the PTD.