Purpose Single-subject experimental designs (SSEDs) represent an important tool in the development and implementation of evidence-based practice in communication sciences and disorders. The purpose of this article is to review the strategies and tactics of SSEDs and their application in speech-language pathology research. Method The authors discuss the requirements of each design, followed by advantages and disadvantages. The logic and methods for evaluating effects in SSED are reviewed as well as contemporary issues regarding data analysis with SSED data sets. Examples of challenges in executing SSEDs are included. Specific exemplars of how SSEDs have been used in speech-language pathology research are provided throughout. Conclusion SSED studies provide a flexible alternative to traditional group designs in the development and identification of evidence-based practice in the field of communication sciences and disorders.

This study examined the effects of variant versus invariant high-probability (high-p) request sequences on the performance of requests to initiate a social bid by young children with emotional-behavioral disorders. In the initial phases of the investigation, a multiple baseline design showed that the delivery of invariant sequences (i.e., high-p requests delivered in the same sequence) produced initial increases in compliance to requests to initiate a social bid to a peer. However, increases were not maintained across the invariant condition. The delivery of variant high-p sequences produced increases in compliance to requests to initiate social bids that were maintained across the variant condition. In a follow-up condition, the number of requests within the pool of the variant and invariant high-p requests were controlled. Results of the follow-up condition replicated those found in the initial condition. Implications for applied use and future research are discussed.

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Over the past decade, aided language stimulation has emerged as a strategy to promote both symbol comprehension and symbol production among individuals who use graphic mode communication systems. During aided language stimulation, an interventionist points to a graphic symbol while simultaneously producing the corresponding spoken word during natural communicative exchanges. The purpose of this study was to determine the impact of aided language stimulation on children with moderate cognitive disabilities. Three preschool children with moderate cognitive disabilities who were functionally nonspeaking participated in the investigation. The investigator implemented a multiple-probe design across symbol sets/activities. Elicited probes were used to determine whether the children increased their comprehension and production of graphic symbols. Results indicated that all 3 children displayed increased symbol comprehension and production following the implementation of aided language stimulation.