This paper seeks to provide an empirically grounded discussion of the critical appraisal model of Evidence-based practice (EBP) in social work practice. Studying real-time treatment decisions, the paper looks ethnographically at an attempt to implement critical appraisal in everyday social work practice, and problematizes some of the assumptions underlying this idea. Whereas critical appraisal tends to view treatment decisions as clear-cut events emanating from autonomous social workers, participant observation shows that decisions emerge over time and are ‘organizational’ rather than individual. Drawing on the notion of ‘logic of care’ and findings from studies of organizational decision-making, a more practice oriented understanding of treatment decision-making is outlined.