What Does the Acceptance and Action Questionnaire (AAQ-II) Really Measure?

• Factor analytic examination of the discriminant validity of the AAQ-II
• The AAQ-II seems to a significant extent measure psychological distress
• Using the AAQ-II might lead to confounded measurements.

The present study seeks to investigate the extent to which the Acceptance and Action Questionnaire (AAQ-II) is successful in discriminating between experiential avoidance/psychological flexibility on the one hand and the supposed outcomes in terms of psychological well-being of having this trait on the other. This was done using exploratory factor analysis on an item pool containing the AAQ-II items, and items designed for the present study to measure distress and acceptance/non-acceptance, to see what factors are identified and on which factor(s) the AAQ-II items had the highest factor loadings. Interestingly, the analysis found the items of the AAQ-II to be more strongly related to items designed to measure distress than items designed to measure acceptance/nonacceptance with minimal references to functional outcomes. The results of the study are interpreted and discussed in relation to the widespread use of the AAQ in both clinical and scientific contexts and given the centrality of the measure in empirically validating the ACT model of psychopathology and treatment.