The percentage of session with reinforcement was calculated by dividing the duration of reinforcement time by the session duration. Reinforcement duration included all of the session time in which the participant had access to the reinforcer identified in the functional analysis. For Gail, reinforcement duration was scored when she was allowed access to both toys and her mother's attention. For Dale, reinforce- ment duration was scored when the analyst or parent removed demands, provided access to the preferred activity, and honored his request for idiosyncratic reinforcers (e.g., sitting in a particular place, changing the movie). For Bob, reinforcement duration was scored when the analyst or parent allowed Bob to play with the iPad or solve the math problems his way.