Using a repertory grid to evaluate psychological change: A review of the evidence and application of the tool to evaluate a brief Cognitive Analytic Therapy-informed intervention for adolescents who self-injure

  • Molly Marsden

Student thesis: Doctor of Clinical Psychology


The thesis investigated how repertory grids (RGs) have been applied to evaluate psychological change following therapy and whether the method is a feasible and acceptable tool to evaluate a pilot, brief Cognitive Analytic Therapy (CAT) informed intervention for adolescence who engage in non-suicidal self-injury (NSSI). The thesis is presented as three papers: (1) a systematic review of the literature; (2) an empirical study using a RG to evaluate a brief CAT-informed intervention; and (3) a critical appraisal of the overall research process. Paper one is a systematic review exploring the use of RGs to evaluate therapy. The systematic search strategy identified 23 relevant papers. The review highlighted that the current evidence base is poor quality. Most of the included studies reflected small-scale practice-based evidence, rather than gold standard randomised control trials. Common ways of implementing the RG included providing elements and eliciting constructs, and analysing the data by comparing element distances or complexity of construing. There is some evidence of significant change on RG metrics, which also mirrors changes on self report measures. However, further rigorous research is required. Paper two is an empirical paper investigating the feasibility and acceptability of using a RG to evaluate a brief CAT-informed intervention for adolescent who engage in NSSI. Eleven adolescents completed the 5-session CAT-informed intervention; nine participants completed pre and post-therapy RGs. Results suggested RGs are an acceptable methodology to administer to adolescents who self-injure. Following the brief CAT informed intervention, participants RGs indicated some change in construing. For example, changes in distance between self and ideal self were observed, which may indicate improvements in participants self-esteem. Larger scale research is required. Paper three is a critical reflection of the research process as a whole. Paper one and two are presented separately, highlighting areas of strength and weakness, and implications for future research. Personal reflections on the experience of completing the thesis are also included.
Date of Award31 Dec 2022
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorPeter Taylor (Supervisor)

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