An Italian validation of the Comparative Psychotherapy Process Scale: Reliability and validity

The Comparative Psychotherapy Process Scale (CPPS) is an instrument designed to measure therapist interventions in a psychotherapy session. The scale includes 20 items divided into two subscales: the PI (psychodynamic-interpersonal) scale, which describes psychodynamic-interpersonal techniques; and the CB (cognitive-behavioural) scale, which includes cognitive-behavioural interventions. The aim of the study was to examine the psychometric properties of the CPPS, comparing the PI and CB subscales with the psychodynamic, cognitive and STTP prototypes, as described by the Psychotherapy Process Q-set(PQS). The sample comprised 94 sessions (N = 94) of psychodynamic and cognitive-behavioural orientation. Two groups of independent raters with excellent interrater reliability (ICC =.78) evaluated the sessions. The results suggest that the CPPS is a valid and reliable instrument that provides a clinically sensitive and psychometrically robust evaluation of a therapist's techniques. The clinical and research implications of the results are discussed.