Thesis (Ph.D.) - Indiana University, Department of Psychological and Brain Sciences, 2018Despite its emergence as an evidence-based practice (Glasgow et al., 2014; Scott & Lewis, 2014), there is a dearth of literature explicating how measurement-based care (MBC) achieves its positive effects in psychotherapy for depression. MBC involves the systematic use of client progress data to guide treatment decisions in therapy (Scott & Lewis, 2014). MBC has three key elements when applied with adherence: a) administration of a symptom measure; b) clinician and client review of symptom scores; and c) clinician and client discussion of symptom scores in session. Simply providing clinicians with feedback regarding client progress improves client outcomes (Lambert et al., 2003). Despite evidence supporting MBC’s effectiveness, a gap exists in the literature regarding the process and mechanisms by which MBC acts to produce change in depression symptoms. The present studies served to close this gap in the literature regarding how MBC is used in session and MBC’s potential mechanisms of action through the use of rigorous qualitative and quantitative modeling procedures. The present studies sought to achieve the following aims: Study 1) To evaluate the variation in clinician approaches to integrating MBC into clinical sessions across treatment; Study 2) To identify patterns and trajectories of clinician MBC adherence following MBC training; and Study 3) To assess session attendance (i.e. treatment engagement) as a putative mechanism by which MBC may act to produce depression symptom change. Study findings suggested that clinicians generally responded to MBC feedback in line with Feedback Intervention Theory (Kluger & DeNisi, 1996), but also highlighted the complexities of clinician assessment and decision-making processes. Observable patterns of clinician MBC adherence post training also emerged, and clinicians demonstrated significant variation in their MBC use. The studies, however, failed to identify treatment engagement as MBC’s mechanism of change. Although additional research is needed to elucidate MBC’s causal processes, findings from the present studies may serve inform strategies to enhance implementation of MBC, improve outcomes for clients seeking psychotherapy, and reduce the burden of disease associated with depression.