An empirical study of the behavior of patients who leave the emergency department without being seen

Queue abandonment has a significant impact on system performance. However, the key drivers for abandonment, particularly in observable systems, are not well understood. To better inform our understanding of abandonment behavior, we study the effect of three operational drivers of abandonment from a hospital emergency department (ED), namely, waiting time, queue length, and observed service rate. We confirm that all three factors affect a patient's propensity for leaving the waiting area without being seen by a physician (LWBS), that is, abandoning the queue. Further, these factors interact with each other in a nonlinear fashion. Both ED crowding and observed service rate influence a patient's perception of waiting time. Moreover, patients are not homogenous in their abandonment response, and we observe behavior that is distinct for patients with severe conditions. Specifically, patients who report to a congested ED with more severe conditions are more inclined to abandon the ED early in the process compared to patients with less severe conditions. Further, we observe that patients with severe conditions who elect to remain in the crowded ED exhibit less sensitivity to waiting time and observed service rate than other patient types. We discuss the implications of this observed abandonment behavior on ED management.