Using a Nonconcurrent Multiple-Baseline Across-Participants Design to Examine the Effects of Individualized ACT at School.

The purpose of the current study was to examine the effectiveness of implementing acceptance and commitment therapy (ACT) with three students who displayed disruptive and off-task behaviors in a classroom. A nonconcurrent multiple-baseline across-participants design with an embedded reversal was used to compare the effects of individualized ACT exercises and treatment-control conditions on classroom behaviors that included on-task behavior, vocal disruption, physical aggression, and classroom disruption. Classroom behaviors were measured during 5-min direct observations using continuous 30-s interval recording. During baseline, all participants displayed low levels of on-task engagement and high or varying rates of challenging behaviors. When the individualized ACT intervention was implemented, participants' on-task and challenging behaviors improved compared to baseline and treatment-control conditions; treatment-control conditions produced mixed results. Implications for school-based treatment programs and collaborative transdisciplinary intervention strategies are discussed. © Association for Behavior Analysis International 2021, corrected publication 2021.