Experimental control in the adapted alternating treatments design: A review of procedures and outcomes

Abstract

The adapted alternating treatments design (AATD) is a single-case experimental design (SCD) that allows for the comparison of two or more instructional procedures on the acquisition of non-reversible behaviors. Recent descriptions of quality indicators and methodological practices (e.g., equating target sets) specific to the AATD may help guide researchers and clinicians interested in using this design, although additional descriptions of best practices are warranted. One area that has not been considered previously are methods to demonstrate experimental control in the AATD; a two-step process that involves experimental procedures and outcomes of the study. The current review analyzed studies published using the AATD in 27 journals to describe researchers' use of methods that allow for the demonstration of experimental control (e.g., no-treatment control condition or combined experimental designs) and, when present, whether participants' responding suggested that potential threats to internal validity were present. The current review found that authors arranged for some type of control procedure in just over half of the reviewed studies. These studies also commonly adhered to recommended practices by frequently assessing responding in the control condition; nevertheless, participant performance suggesting potential threats to internal validity were common. Recommended practices and areas for future research are considered.