The CES-D-10, QIDS-SR, and DASS-21-DEP are brief self-report instruments for depression that have demonstrated strong psychometric properties in clinical and community samples. However, it is unclear whether any of the three instruments is superior for assessing depression and treatment response in an acute, diagnostically heterogeneous, treatmentseeking psychiatric population. The present study examined the relative psychometric properties of these instruments in order to inform selection of an optimal depression measure in 377 patients enrolled in a psychiatric partial hospital program. Results indicated that the three measures demonstrated good to excellent internal consistency and strong convergent validity. They also demonstrated fair to good diagnostic utility, although diagnostic cut-off scores were generally higher than in previous samples. The three measures also evidenced high sensitivity to change in depressive symptoms over treatment, with the QIDS-SR showing the strongest effect. The results of this study indicate that any of the three depression measures may satisfactorily assess depressive symptoms in an acute psychiatric population. Thus, selection of a specific assessment tool should be guided by the identified purpose of the assessment. In a partial hospital setting, the QIDS-SR may confer some advantages, such as correspondence with DSM criteria, greater sensitivity to change, and assessment of suicidality.Keywords Depression . Assessment . Psychometric . Center for the epidemiological studies of depression-short form . Quick inventory of depressive symptomatology-self-report version . Depression anxiety and stress scales-21-item versionThe identification of valid, clinically useful, and efficient assessment tools is particularly important in the context of increasing emphasis on evidence-based mental healthcare and outcomes evaluation (Hunsley and Mash 2005). Yet, far less attention has been paid to issues related to the evidence-based assessment of depression in real-world clinical settings, relative to the emphasis placed on evidence-based treatment approaches in these settings (Barlow 2005;Hunsley and Mash 2005). Although there are a number of instruments available (see Joiner et al. 2005), there is a dearth of empirically-based information to guide the selection of depression measures in acute, heterogeneous treatment populations. Assessing treatment progress and outcome in acute treatment settings (e.g., inpatient, residential, or partial hospitals) is just as critical as other settings and warrants its own empirically-based evidence given the unique characteristics of these settings (e.g., very limited time to provide treatment in a population with high levels of symptom severity, comorbidity, functional impairment, and suicide risk).Although the clinical benefits of using evidence based assessments to monitor treatment outcome are clear (e.g., Duffy et al. 2008;Slade et al. 2006), they remain underutilized in psychiatric settings (Weiss et al. 2009;Zimmerman and McGlinchey 2008;Gilbody ...