Measuring effective capacity in an emergency department

PURPOSE: The purpose of this paper is to show how elements from queueing theory can be used to obtain objective measures of effective capacity in the triage function at Skaraborg Hospital in Sweden without direct observation of the function itself. DESIGN/METHODOLOGY/APPROACH: Approximately 30,000 patients arrived to the emergency department at Skaraborg Hospital in Sweden during 2011. The exact time of arrival and the exact time of triage were recorded for each patient on an individual level. Basic queueing theory uses arrival rates and system capacity measures to derive average queueing times. The authors use the theoretical relation between these three measures to derive system capacity measures based on observed arrival rates and observed average queueing times. FINDINGS: The effective capacity in the triage process is not a linear function of the number of nurses. However, the management of capacity seems well adapted to the actual demand, even though service levels vary substantially during the day and night. ORIGINALITY/VALUE: This paper uses elements from queueing theory in an innovative way to measure the effective capacity of a service process without direct observation, thereby also avoiding the potential risk of the Hawthorne effect.