title: Measuring effective capacity in an emergency department.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Technology Management and Economics, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Lantz
authors.forename: Peter
authors.initials: P
authors.lastname: Rosén
mesh_terms: D017598:Efficiency, Organizational; D004636:Emergency Service, Hospital / Q000458:organization & administration*; D006801:Humans; D019984:Quality Indicators, Health Care; D013548:Sweden; D014218:Triage; D014850:Waiting Lists
keywords: Capacity measurement; Emergency department; Hawthorne effect; Performance management; Performance measurement; Performance monitoring; Queueing theory; Sweden; Triage function