Abstract
This paper discusses methodologic issues in comparing the efficacy of two or more interventions in augmentative and alternative communication (AAC). The extant database of AAC interventions was searched for studies using comparative single-subject experimental designs. A brief content review of identified studies is presented. Next, methodologic issues related to the selected decision points in comparative evaluations are discussed and potential solutions are presented. This discussion and presentation of solutions are intended to assist clinical researchers in producing and consuming published comparative efficacy studies. Comparative investigations are posited as essential for the development of data-based recommendations about which interventions should be used to train specific individuals given certain communicative tasks and goals.