The Authenticity Scale as an outcome measure for psychological therapies

Abstract

Background. Counselling and psychotherapy services are under pressure to evidence clinical effectiveness. However, many of the outcome measures in use are based on the ‘disease model’: a paradigm that is at odds with several key psychotherapy approaches, including the humanistic approach. This has led to calls for psychometrically sound outcome measures that emphasise growth and well-being. One such measure is the Authenticity Scale (AS), based on the Rogerian concept of congruence. Authenticity is a core construct within humanistic psychology and the person-centred model of psychotherapy, and the measure has been developed specifically for use as an outcome tool for counselling and psychotherapy. Despite this, no research to date has assessed the validity of the AS in this way.
Aims. The aim of this thesis is to investigate the psychometric properties of the AS, and how it functions as an outcome measure, specifically looking at its reliability, validity, acceptability, and sensitivity to change in a clinical sample.
Methods. The thesis consists of two studies. Study 1 is a systematic review of the literature regarding the AS in general populations, collating psychometric data from 60 publications into a narrative synthesis and meta-analysis. In Study 2, a total of 67 clients receiving psychotherapy completed the AS and the CORE-10 periodically over the course of their therapy. Sensitivity to change was assessed using pre- and post-therapy comparisons, and multilevel modelling.
Results. In Study 1, the AS showed excellent psychometric properties in the majority of samples, confirming its potential as a psychotherapy outcome measure. In Study 2, the AS was internally reliable in the clinical sample, and showed convergent validity with the CORE-10 measure of psychological distress. Multilevel modelling indicated that the AS was sensitive to change, with participants’ scores increasing significantly over the course of therapy. These findings indicate that the AS may be a psychometrically valid and reliable outcome measure for use in the psychological therapies.

Date of Award	28 Aug 2019
Original language	English
Awarding Institution	University of Roehampton
Supervisor	Mick Cooper (Supervisor) & Chris Evans (Supervisor)