Objective: The aims of the study were to evaluate the effects of using the Partners for Change Outcome Management System (PCOMS) in psychotherapy and to explore potential moderators of the effect. Method: A comprehensive literature search including grey literature was conducted to identify controlled outcome studies on the PCOMS, randomized (RCTs), or non-randomized trials (N-RCT). Results: The literature search identified 18 studies, 14 RCTs, and four N-RCTs, including altogether 2910 participants. The meta-analysis of all studies found a small overall effect of using the PCOMS on general symptoms (g = 0.27, p = .001). The heterogeneity of the results was substantial. Moderation analyses revealed no effect of the PCOMS in psychiatric settings (g = 0.10, p = .144), whereas a positive effect was found in counseling settings (g = 0.45, p < .001), although almost all of these studies were characterized by a positive researcher allegiance and using the PCOMS Outcome Rating Scale (ORS) as the only outcome measure. Conclusion: The meta-analysis revealed a small overall effect of using the PCOMS, but no effect in psychiatric settings. The positive results in counseling settings might be biased due to researcher allegiance and use of the ORS as the only outcome measure.
Keywords: Partners for Change Outcome Management System (PCOMS); Routine Outcome Monitoring (ROM); client feedback; meta-analysis; psychotherapy outcome.