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

Author: Schlosser Ralf   Braun Ursula  

Publisher: Informa Healthcare

ISSN: 0743-4618

Source: Augmentative & Alternative Communication, Vol.10, Iss.4, 1994-01, pp. : 207-223

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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. The following variables are considered crucial, and are therefore discussed as such, to an accurate evaluation of generalization effectiveness: (a) the strategies used to induce generalization; (b) the number and type of dimensions involved; and (c) the design options selected to assess generalization effectiveness. As a further conceptual clarification of efficacy, it is proposed that treatment effects, including intermediate, instrumental, and ultimate effects, be distinguished, based on their roles in the treatment process. To date, AAC efficacy evaluation has primarily been concerned with intermediate effects. The authors propose that the evaluation of instrumental and ultimate effects also be considered in the evaluation of AAC interventions.