Emerg Med J 29:868-871 doi:10.1136/emermed-2011-200646
  • Original articles

Emergency department crowding: prioritising quantified crowding measures using a Delphi study

  1. P John Clarkson1
  1. 1Engineering Design Centre, Department of Engineering, University of Cambridge, Cambridge, UK
  2. 2Emergency Department, Addenbrooke's Hospital Cambridge University Hospitals NHS Foundation Trust, Cambridge, Cambridgeshire, UK
  1. Correspondence to Ms K Beniuk, Engineering Design Centre, Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK; kb424{at}
  1. Contributors AAB and KB conceived the study and undertook recruitment of participants. KB conducted the study, and was responsible for data collection and analysis. AAB and PJC supervised the completion of this research and provided advice on study design. KB drafted the manuscript and all authors contributed to its revision. KB takes responsibility for the paper as a whole.

  • Accepted 3 November 2011
  • Published Online First 23 December 2011


Aims Emergency department (ED) crowding has been associated with a number of negative health outcomes, including unnecessary deaths, increased waiting times and a decrease in care quality. Despite the seriousness of this issue, there is little agreement on appropriate crowding measures to assess crowding effects on ED operations. The objective of this study was to prioritise a list of quantified crowding measures that would assess the current state of a department.

Methods A three round Delphi study was conducted via email and an Internet based survey tool. The panel consisted of 40 professionals who had exposure to and expertise in crowding. Participants submitted quantified crowding measures which, through three rounds, were evaluated and ranked to assess participant agreement for inclusion.

Results The panel identified 27 measures of which eight (29.6%) reached consensus at the end of the study. These measures comprised: (1) ability of ambulances to offload; (2) patients who leave without being seen or treated; (3) time until triage; (4) ED occupancy rate; (5) patients' total length of stay in the ED; (6) time to see a physician; (7) ED boarding time; and (8) number of patients boarding in the ED.

Conclusions This study resulted in the identification of eight quantified crowding measures, which present a comprehensive view of how crowding is affecting ED operations, and highlighted areas of concern. These quantified measures have the potential to make a considerable contribution to decision making by ED management and to provide a basis for learning across different departments.


  • Funding UK Engineering and Physical Sciences Research Council (EPSRC), grant No EP/E001777/1. The role of the EPSRC was to provide partial funding for KB's PhD training. The researchers were independent of the EPSRC. At no time did the EPSRC attempt to influence the direction of the research undertaken.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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