The Phase Model of Psychotherapeutic Outcome: Validation of the ``Questionnaire for the Evaluation of Psychotherapeutic Change Processes'' (FEP)

Abstract

Sufficiently theoretically founded and validated measures in German language to assess psychotherapeutic change are rare. The German Questionnaire for the Evaluation of Psychotherapeutic Change Processes (FEP) was designed on the basis of the Phase model of psychotherapeutic outcome. In the present study, the psychometric properties of the FEP and especially its factorial structure are validated. Psychometric values were calculated and confirmatory factor analyses were performed (outpatient sample, N = 427). Itemindices, reliability - with exception of retest-reliability - and validity reached overall good to very good values. The best model-fit indices were obtained for the 3-factor-structure corresponding to the FEP-subscales Well-being, Symptoms and Interpersonal relations which represent the dimensions postulated by the Phase model. The FEP proved to be a psychometrically well-founded transdiagnostic measure of outcome and change which represents multidimensional phases of change. Its application in outcome monitoring is recommended.