A study was undertaken to make an evidence-based case for the value of social workers in efficient discharge of patients from acute care hospitals and to assist hospital managers in making informed staffing decisions. Hospital administrative databases from March 1 to November 30, 2008, were used for the analysis of inpatient discharges on days when social workers were on vacation compared with days fully staffed with social workers. Two performance measures, daily discharge rate and average length of stay, were evaluated. During the study period, 1825 patients were discharged from the General Internal Medicine inpatient service. Team discharge rates were significantly lower on social work vacation Fridays versus regular Fridays. In contrast, the average length of stay for patients discharged on social work vacation Fridays was significantly shorter than that for patients discharged on regular Fridays. It was concluded that daily discharge rate better quantified the role of social work in patient discharge. More generally, these results provide preliminary support for the need for adequate social work staffing in timely and efficient patient discharge.