Abstract
Traditionally, communication intervention outcomes have been described in terms of changes in such factors as the rate of language acquisition and extended symbol vocabulary. In recent years, such outcome expectancies have been questioned for individuals who do not use symbols to communicate. To date, there are no standard criteria for the establishment of effective intervention goals and methods for these individuals, nor is it known if intervention goals are being attained. This lack of information is the result of difficulties associated with defining both the target population and how the concepts of communication, outcome, and effect relate to their needs. These difficulties result in practical problems with respect to both assessment and intervention, as well as uncertainty with regard to how to interpret evidence of change as a consequence of intervention. Difficulties and possible solutions are discussed in relation to the efficacy of communication intervention for persons who are presymbolic communicators.