The CompACT-10: Development and validation of a Comprehensive assessment of Acceptance and Commitment Therapy processes short-form in representative UK samples

Abstract

The Comprehensive assessment of Acceptance and Commitment Therapy Processes (CompACT) has frequently been deployed within contextual behavioural research and shown to reliably measure psychological flexibility. However, at 23 items, the scale is relatively long and burdensome, limiting suitability for some measurement contexts, assessment schedules, and respondent groups. Although abbreviated versions of the CompACT have been proposed within the literature, these have arisen from efforts to improve the psychometric properties of the original scale (e.g., removing less stable items) versus any a priori goal of developing a short-form scale. In this study, we describe the development of a psychometrically robust short-form of the CompACT (CompACT-10), and explore and confirm the measure's factor structure, stability, validity, and reliability in two moderately large, independent, UK-representative samples (Ns = 401 and 399). The CompACT-10 demonstrated acceptable internal consistency, for both full- and sub-scale indices, and converged and diverged in theory-consistent ways with other measured variables; higher CompACT-10 scores (indicating greater psychological flexibility) were associated with lower psychological distress and greater levels of health and wellbeing. Confirmatory Factor Analysis of the new measure replicated the three-factor model of the original CompACT, suggesting that the CompACT-10 retains the theoretical scope of the longer measure. The research provides promising evidence that the CompACT-10 is a reliable and valid tool for the brief assessment of psychological flexibility.