A quantitative synthesis of functional analytic psychotherapy single-subject research

Functional Analytic Psychotherapy (FAP) is a contextual behavioral therapy that utilizes behaviorism within the therapeutic relationship to implement in-session changes with the idea that these changes will generalize outside of session. The therapist focuses on reinforcing adaptive behavior and decreasing problematic behavior. Although FAP has existed as a therapy for nearly three decades, there is a limited amount of research examining its efficacy, and the majority of FAP efficacy studies use single-subject data. The current study aims to synthesize data from 20 FAP single-subject design research studies in order to provide a quantitative estimate of its efficacy. The metrics used to synthesize the data in this study include percentage of non-overlapping data (PND), split-middle trend estimation (SMTE), reliable change index (RCI), and Swanson's dsw. For PND and SMTE analyses the overall mean effect sizes fell into the "questionably effective" to "fairly effective" classification. RCIs were consistently classified as "statistically reliable" and swanson's dsw analyses indicated that differences were large and reliable.