Trained research assistants collected direct observation data. Frequency counts were used to record instances of problem behavior during the functional analysis and choice analysis. For Ian, yelling and screaming nearly always preceded aggression and property destruction, which were severe at times, resulting in significant injury to others or damage to the environment. Thus, for safety reasons, yelling or screaming (e.g., any instance of a verbal noise or utterance at a volume louder than a typical speaking voice) served as the target behavior.