Working Paper | HBS Working Paper Series | 2014

The Diseconomies of Queue Pooling: An Empirical Investigation of Emergency Department Length of Stay

by Hummy Song, Anita L. Tucker and Karen L. Murrell


We conduct an empirical investigation of the impact of queue management on patients' average wait time and length of stay (LOS). Using an Emergency Department's (ED) patient-level data from 2007 to 2010, we find that patients' average wait time and LOS are longer when physicians are assigned patients under a pooled queuing system with a fairness constraint compared to a dedicated queuing system with the same fairness constraint. Using a difference-in-differences approach, we find the dedicated queuing system is associated with a 17 percent decrease in average LOS and a nine percent decrease in average wait time relative to the control group—a 39-minute reduction in LOS and a four-minute reduction in wait time for an average patient of medium severity in this ED. Interviews and observations of physicians suggest that the improved performance stems from the physicians' increased ownership over patients and resources that is afforded by a dedicated queuing system, which enables physicians to more actively manage the flow of patients into and out of ED beds. Our findings suggest that the benefits from improved flow management in a dedicated queuing system can be large enough to overcome the longer wait time predicted to arise from non-pooled queues. We conduct additional analyses to rule out alternate explanations for the reduced average wait time and LOS in the dedicated system, such as stinting and decreased quality of care. Our paper has implications for health care organizations and others seeking to reduce patient wait time and LOS without increasing costs.

Keywords: pooling; queue management; strategic servers; social loafing; empirical operations; health care; fairness; Management Practices and Processes; Service Delivery; Health Care and Treatment; Health Industry;


Song, Hummy, Anita L. Tucker, and Karen L. Murrell. "The Diseconomies of Queue Pooling: An Empirical Investigation of Emergency Department Length of Stay." Working Paper. (October 2014.)