This systematic review and meta-analysis examines the impact of measuring, monitoring, and feeding back information on client progress to clinicians while they deliver psychotherapy. It considers the effects of the 2 most frequently studied routine outcome monitoring (ROM) practices: The Partners for Change Outcome Management System and the Outcome Questionnaire System. Like other ROM practices, they typify attempts to enhance routine care by assisting psychotherapists in recognizing problematic treatment response and increasing collaboration between therapist and client to overcome poor treatment response. A total of 24 studies were identified and considered suitable for analysis. Two-thirds of the studies found that ROM-assisted psychotherapy was superior to treatment-as-usual offered by the same practitioners. Mean standardized effect sizes indicated that the effects ranged from small to moderate. Feedback practices reduced deterioration rates and nearly doubled clinically significant/reliable change rates in clients who were predicted to have a poor outcome. Clinical examples, diversity considerations, and therapeutic advances are provided. (PsycINFO Database Record (c) 2018 APA, all rights reserved).