Effectiveness of the PECS Phase III app and choice between the app and traditional PECS among preschoolers with ASD

We investigated the efficacy of a tablet-computer-based Picture Exchange Communication System (PECS) application for use with three preschoolers with ASD and investigated participant preference for the app versus traditional PECS (i.e., with a physical communication book) once the participants demonstrated minimal levels of mastery of both. We implemented a single-case multiple baseline design to determine the efficacy of the app. Results indicated that participants rapidly demonstrated above-chance level mastery of the app. Following mastery, two participants demonstrated a preference for the app, while the other preferred the traditional PECS communication book.