Efficacy of AAC interventions: Methodologic issues in evaluating behavior change, generalization, and effects

Abstract

The purpose of this paper is to discuss selected methodologic issues related to the evaluation of the efficacy of interventions in augmentative and alternative communication (AAC). Previous literature is summarized for the evaluation of the effectiveness of AAC intervention programs as an organizational framework. Efficacy is then defined as an umbrella term, comprising not only effectiveness, but also efficiency and effects. Two indices, previously insufficiently addressed, are discussed in detail: (1) causal behavior change and (2) generalization. It is emphasized that demonstrations of causal behavior change require experimental research methodology rather than case study methodology. Generalization is defined and distinguished into stimulus and response generalization as two broad dimensions of generalization. Researchers are encouraged to explore the wide range of stimulus generalization conceivable in AAC and to evaluate whether collateral effects correspond conceptually to response generalization. ...