Ongoing, Explicit, and Direct Functional Assessment is a Necessary Component of ACT as Behavior Analysis: A Response to Tarbox et al. (2020).

Tarbox et al. (2020) offered preliminary functional analyses and practical guidelines for incorporating acceptance and commitment therapy (ACT) within the scope of practice of applied behavior analysis (ABA). Although we agree that this is a needed goal, the approach taken by the authors gives rise to important conceptual, ethical, and practical concerns that warrant further discussion. In particular, we propose that explicit functional assessment of behavior (FA) is necessary in any intervention said to be ABA, and we wonder about the apparent omission of explicit FA throughout the article. We question what we read as the authors' tacit assertion that the functions of verbal stimuli can be inferred based on behavioral topography, that the function of verbal behavior can likewise be inferred based on form, and that behavior-behavior relations are both causal and predictive of behavior, irrespective of context. Furthermore, we consider whether a number of procedures for functional assessment presented in the article under consideration are consistent with established ABA best practices. Finally, we discuss the extent to which ACT interventions absent explicit FA in ABA interventions introduces the possibility that the interventions may do harm, arguing that further discussion around competence and scope of ethical practice for behavior analysts who wish to incorporate ACT into their work is needed. © Association for Behavior Analysis International 2021.