Similarities and differences between retrospective and pre–post measurements of outcome

In past years, various theoretical conceptualizations of therapeutic outcome have been proposed. Differences based on pre–post and retrospective measurements were found (Michalak et al., 2003 Michalak, J., Kosfelder, J., Meyer, F. and Schulte, D. 2003. Messung des Therapieerfolgs. Veränderungsmasse oder retrospektive Erfolgsbeurteilung [Measurement of therapy success: Pre-post effect sizes and retrospective success evaluation]. Zeitschrift für Klinische Psychologie, 32: 94–103. [Crossref], [Web of Science ®] , [Google Scholar]). In the current study, a sample of 263 patients completed seven questionnaires pre- and posttreatment or retrospectively. The results were examined with explorative and confirmative factor analyses. The authors found high intercorrelations and internal consistency over all seven questionnaires (Cronbach's α = .85). In confirmatory factor analyses, a three-factor model encompassing global retrospective, multi-item retrospective, and pre–post measures has the best fit indexes. Retrospective and pre–post measures are equally mood dependent at posttreatment measurements. Regression effects are observed only with pre–post measures.