Randomized controlled trials have shown that using client feedback obtained from routine outcome monitoring can lead to better clinical outcomes in psychotherapy. However, existing randomized controlled trial studies did not address the between-person and within-person effects of routine outcome monitoring simultaneously. To fill this critical gap, this study conducted a multilevel analysis to explore the effect of therapist utilization of client symptom outcome data in a naturalistic practice setting. Participants were 26 therapist trainees and their 456 clients who conducted 5,917 sessions in total. Clients completed the Outcome Questionnaire (OQ)-45.2 prior to every session, and we used de-identified data to code whether each OQ report was reviewed by the therapist the session, or not reviewed by the therapist. Multilevel analysis showed that, within the same therapist-client dyad, sessions where the therapist reviewed the client's OQ score beforehand (rather than afterhand) showed significantly larger symptom improvement by the next session than sessions without such a review. Additionally, comparing clients within a therapist's caseload, a higher percentage of sessions where the therapist reviewed OQ scores before (rather than after) was associated with quicker symptom recovery for those clients. Finally, comparing therapists, those who reviewed client OQ scores more frequently before (rather than after) therapy sessions achieved faster client symptom recovery across all clients. Practical implications of the findings were discussed. (PsycInfo Database Record (c) 2025 APA, all rights reserved).
