Doctoral Student

Hummy Song

Hummy Song is a PhD candidate in Health Policy Management at the Harvard Graduate School of Arts and Sciences and Harvard Business School. Her research focuses on health care operations, specifically factors that affect the productivity of the health care workforce and the implications for operational efficiency and quality of care.

Hummy received an AB in History with a secondary field in Psychology from Harvard College. She holds an MPP from the Harvard Kennedy School of Government, where she focused on global health and development policy. Prior to her master’s program, she worked with the Campaign for Tobacco-Free Kids on international tobacco control policy development and implementation. She also worked as a policy analyst at The Century Foundation.

During and since her master’s program, Hummy has worked with several organizations that are engaged in health care delivery and community health worker programs in the U.S. and in developing countries. She has designed willingness-to-pay studies for global health organizations, and has executed randomized control trials and observational studies in sub-Saharan Africa on health-related topics.

Currently, she is working on projects that examine various operational and organizational factors that may affect worker productivity and quality of care. 

Working Papers

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

    We conduct an empirical investigation of the impact of two different queue management systems on throughput times. Using an Emergency Department's (ED) patient-level data (N = 231,081) from 2007 to 2010, we find that patients' lengths of stay (LOS) were longer when physicians were assigned patients under a pooled queuing system, compared to when each physician operated under a dedicated queuing system. The dedicated queuing system resulted in a 10 percent decrease in LOS—a 32-minute reduction in LOS for an average patient of medium severity in this ED. We propose that the dedicated queuing system yielded shorter throughput times because it provided physicians with greater ability and incentive to manage their patients' flow through the ED from arrival to discharge. Consistent with social loafing theory, our analysis shows that patients were treated and discharged at a faster rate in the dedicated queuing system than in the pooled queuing system. We conduct additional analyses to rule out alternate explanations, such as stinting on care and decreased quality of care. Our paper has implications for health care organizations and others seeking to reduce throughput time, resource utilization, and costs.

    Keywords: pooling; queue management; strategic servers; social loafing; empirical operations; health care; 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." Harvard Business School Working Paper, No. 14-050, December 2013.