Hummy Song

Hummy Song

Assistant Professor of Operations, Information, and Decisions, University of Pennsylvania Wharton School

Dissertation Title: "Drivers of Physician Productivity and Performance: The Role of Queuing Systems, Relative Performance Feedback, and Cohort Turnover"

This dissertation investigates how operational choices about the design of work systems in health care settings impact the way physicians deliver care. Across three studies, I examine the following potential drivers of physician productivity and performance: queuing systems, relative performance feedback, and cohort turnover.

In Chapter 1 – coauthored with Anita L. Tucker and Karen L. Murrell – we analyze the impact of pooled versus dedicated queuing systems on wait times and processing times in an emergency department (ED) setting. We find that – in contrast to what traditional queuing theory would predict – patients’ average wait times and lengths of stay (LOS) are shorter when physicians are assigned patients under a dedicated queuing system. Interviews and observations of physicians suggest that improved performance under a dedicated system stems from physicians’ increased ownership over patients and resources, which enables them to more actively manage the flow of patients.

In Chapter 2 – coauthored with Anita L. Tucker, Karen L. Murrell, and David R. Vinson – we examine whether and how publicly (as opposed to privately) disclosing relative performance feedback (RPF) affects the speed and quality with which physicians deliver care in the ED. We find that public disclosure of RPF enables the identification and diffusion of best practices around ED workflow, which ultimately helps reduce physician processing times without sacrificing quality.

In Chapter 3 – coauthored with Robert S. Huckman and Jason R. Barro – we explore when and how cohort turnover affects hospital operational performance in U.S. teaching hospitals. Despite the anticipated nature of the cohort turnover and the supervisory structures that exist in teaching hospitals, we find that the annual cohort turnover of resident physicians in July results in increased resource utilization; we find limited evidence of negative effects on quality. Particularly in major teaching hospitals, we find evidence of a strong anticipation effect in which hospitals exhibit a gradual trend of decreasing performance that begins several months before the actual cohort turnover. Together, these studies advance our understanding of how certain operational choices enable physicians to deliver care more efficiently without adversely affecting the quality of care. In doing so, this dissertation contributes to the literatures on health care operations, behavioral operations, and the productivity of service and knowledge workers. In addition, it provides practical implications for hospital managers who make important operational decisions that affect the efficiency and quality of care delivery.


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