Applying queueing theory to the study of emergency department operations: a survey and a discussion of comparable simulation studies

Queueing models are important tools for the design and management of emergency departments (EDs). In this survey, we examine the contributions of queueing theory (QT) in modeling EDs and assess the strengths and limitations of this application. We include a direct comparison to discrete-event simulation when applied to similar problems, and discuss data acquisition and challenges associated with each method. Specifically, we review applications of QT from the perspective of demand- and supply-side problems, as well as various methodological innovations developed to address the complexities of ED operations. In reviewing relevant articles published since 1970, we found that queueing models tend to oversimplify operations and underestimate congestion levels (especially for smaller systems), and obtain less realistic results than comparable simulation models. The combination of queueing and simulation is shown to be a powerful approach. Future efforts should exploit this and more widely available real-world data.