Key points are not available for this paper at this time.
In this concluding paper related to subject selection in augmentative and alternative communication (AAC) research, four issues previously discussed are brought together: the representativeness/homogeneity of subjects, methodological design, external validity, and research economics. In light of these particular issues, a set of heuristics for making appropriate subject choices is provided.
Higginbotham et al. (Sun,) studied this question.