Communication Complexity Scale (CCS) scores for 269 minimally verbal participants were examined to determine if communicator behavior and task and communicator characteristics were related to scores in a manner consistent with theoretical and research evidence expectations. Each participant completed an interactive assessment with 6 joint attention tasks and 6 behavior regulation tasks. Caregivers completed the Vineland Adaptive Behavior Scales II. Results indicated (a) joint attention tasks yielded lower scores than behavior regulation tasks, (b) older participants had lower scores, (c) individuals with autism spectrum disorder scored more similarly than those without, (d) the difference between joint attention and behavior regulation scores was greater for the autism spectrum disorder group, and (e) adaptive behavior was significantly positively related to complexity scores.