Validation of the German Version of the Comparative Psychotherapy Process Scale

The Comparative Psychotherapy Process Scale (CPPS) is a 20-item scale which aims to capture technical features distinguishing cognitive behavioral (CBT) from psychodynamic (PD) psychotherapy (and vice versa) in two corresponding subscales (CBT and PD Subscale). Our objective was to validate a German self-report version of the CPPS regarding a previous psychotherapy session in a psychotherapist- and in a patient-version. Fifty-three psychotherapists and their 53 patients answered to the according German CPPS Scale as well as to specific subscales of the Multitheoretical List of Therapeutic Interventions self-report-instrument (MULTI-30 subscales) assessing CBT- and PD-specific intervention characteristics. We analyzed (a) the correlation of the CPPS with the MULTI-30 subscales, (b) the ability of the CPPS to distinguish whether therapy sessions were either CBT or PD using logistic regression, and (c) the correlation between psychotherapists' and patients' self-report regarding the preceding session (correlation). Both the psychotherapist- and the patient-version showed acceptable to good values of internal consistencies (alpha = .78-.84). The CBT and PD Subscales of the MULTI-30 correlated with the CPPS subscales in both versions (CBT: r(s) = .85 [psychotherapist-version] and .80 [patient-version], PD: r(s) = .79 [both versions]). Subscales correctly discriminated whether the previous session was a CBT or a PD session (correct predictions in 88.7% in the psychotherapist-version, 73.6% in the patient-version; chi(2) >=; 14.03, p < .001). The German version of the CPPS is a promising instrument to facilitate research on CBT- and PD-specific psychotherapy processes.