Comprehensive assessment of Acceptance and Commitment Therapy processes (CompACT): Measure refinement and study of measurement invariance across Portuguese and UK samples

The need for a transnational validation is imperative at the stage of development CompACT, self-report measure psychological flexibility. This study aimed to translate, validate and test factor structure Portuguese version CompACT conduct measurement invariance analysis comparing scale's performance in UK samples. Results from an Exploratory Factor Analysis demonstrated that statistically performed better without 5 items Openness Experience subscale. 18-item Portuguese-adapted presented significant correlations expected directions with magnitudes AAQ-II, CFQ-7, MAAS, CAQ-8, DASS-21. Partial metric was between original sample. non-correspondence responses these versions may be due differences British cultures. contributes adaptation language refinement this instrument flexibility, appears adequate use lack complete found across samples highlights importance psychometrically analyzing instruments before cultural contexts distinct one targeted measure's study. • CompACT's partial invariance. refined structure. showed key measures directions.