Development and validation of a short form of the Comprehensive assessment of Acceptance and Commitment Therapy processes (CompACT-SF)

Morris, Jessica (2019) Development and validation of a short form of the Comprehensive assessment of Acceptance and Commitment Therapy processes (CompACT-SF). DClinPsy thesis, University of Nottingham.

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Abstract

Psychological flexibility is the purported mechanism of chance in Acceptance and Commitment Therapy (ACT), theoretically underpinned by the six processes which make up the ACT ‘hexaflex’ model. However, it has been suggested that the processes can be clustered into three dyadic processes, namely ‘Openness to Experience’, ‘Valued Action’, and ‘Behavioural Awareness’.

The Comprehensive Assessment of Acceptance and Commitment Therapy Processes (CompACT; Francis et al., 2016) was developed as a new general measure of ACT processes, in response to criticisms relating to the Acceptance and Action Questionnaire (AAQ-II) being a conflated measure of distress. The three-factor structure of the CompACT, and its reliability and validity, were subsequently demonstrated in an independent sample (Bayliss et al., 2018). However, at 23 items in length, the full CompACT measure may present an undue respondent burden for use in idiographic research or as a therapy tracking measure, thus indicating the need for an abbreviated measure.

The present research concerns the development and validation of a short form of the CompACT (the CompACT-SF). To derive the short form, the 23 CompACT items were assessed according to internal, intuitive, and external criteria; this included: 1) internal scale reliability assessed by Cronbach’s ; 2) inter-item correlation assessed by Pearson’s r; 3) factor loadings in a Confirmatory Factor Analysis (CFA); 4) judgements regarding content coverage and semantic redundancy; 5) association with measures of psychological flexibility, wellbeing, and distress. The internal reliability, concurrent and convergent validity, and factor structure of the new CompACT-SF were assessed in an independent sample (N = 571).

The CompACT-SF demonstrated acceptable levels of internal reliability ( > .70) and good convergent validity via significant correlation with the AAQ-II (r = -.69; p < .01). Concurrent validity with measures of distress and well-being as demonstrated by significant association with the DASS-21 (r = -.613; p < .01) and SF12v2 Mental Health scale (r = 61; p < .01), respectively. A CFA supported the three-factor model, with acceptable factor loadings (loadings > .50) and good performance on various indices of model fit.

This research provides promising evidence that the CompACT-SF may be a useful, reliable, and valid tool for the brief assessment of psychological flexibility, in both research and clinical practice.

Item Type: Thesis (University of Nottingham only) (DClinPsy)
Supervisors: Golijani-Moghaddam, Nima
Dawson, David
Keywords: Acceptance and Commitment Therapy, Psychometrics, Short-form psychometrics
Subjects: W Medicine and related subjects (NLM Classification) > WM Psychiatry
Faculties/Schools: UK Campuses > Faculty of Medicine and Health Sciences > School of Medicine
Item ID: 57105
Depositing User: Morris, Jessica
Date Deposited: 10 Jan 2020 14:33
Last Modified: 06 May 2020 11:33
URI: http://eprints.nottingham.ac.uk/id/eprint/57105

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