Psychometric Properties of the Persian Version of the Clients' Experience of Therapy Scale (CETS)

Abstract

Background: Assessing clients' subjective experiences is essential for understanding psychotherapy processes and outcomes beyond symptom reduction. Objectives: This study aimed to evaluate the psychometric properties of the Persian version of the Clients' Experience of Therapy Scale (CETS) in an Iranian sample. Methods: In this cross-sectional study, 458 participants with current or prior psychotherapy experience completed the CETS, the Real Relationship Inventory-Client (RRI-C), the In-Session Patient Affective Reactions Questionnaire (SPARQ), and the Rift In-Session Questionnaire (RISQ). Confirmatory factor analysis (CFA) was conducted to examine the proposed five-factor structure. Internal consistency, convergent validity, and discriminant validity were also assessed. Results: The initial CFA indicated suboptimal model fit. After theoretically justified modifications involving residual covariances between conceptually related items, the revised five-factor model demonstrated acceptable fit indices (CFI = 0.93, GFI = 0.92, RMSEA = 0.07). The total scale demonstrated good internal consistency (Cronbach's α = 0.84), and subscale reliability coefficients ranged from 0.66 to 0.88. The CETS total score was positively correlated with the RRI-C and SPARQ Positive Affect and negatively correlated with the RISQ and SPARQ Negative Affect, supporting convergent and discriminant validity. Conclusions: The Persian version of the CETS demonstrated acceptable preliminary psychometric properties in an Iranian sample and may serve as a useful process-oriented measure for assessing clients’ subjective experiences of psychotherapy. Further research is needed to replicate the factor structure and evaluate additional psychometric properties across diverse clinical populations.