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Emergency department crowding: towards an agenda for evidence-based intervention
  1. Zoë Slote Morris1,
  2. Adrian Boyle2,
  3. Kathleen Beniuk1,
  4. Susan Robinson2
  1. 1Engineering Design Centre (EDC)Department of Engineering,University of Cambridge,Cambridge, UK
  2. 2Emergency Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
  1. Correspondence to Zoë Slote Morris, Engineering Design Centre (EDC), University of Cambridge, Cambridge CB4 1YG, UK; zsm20{at}


Objective To determine the causes of emergency department (ED) crowding and to identify evidence-based solutions.

Design The review used a ‘conceptual synthesis’ approach to identify knowledge and opinion around the issue of ED crowding, not just effective interventions. Recommendations from the literature were classified according the quality of evidence and the extent to which they were under ED control.

Data sources SCOPUS and ISI were searched for studies of ‘ED’ AND ‘crowding OR overcrowding’ and backward citation retrieval was undertaken. To help identify systematic review evidence of effective interventions, the Cochrane Database, the National Institute of Health and Clinical Excellence (NICE) and NHS Evidence were searched. A Google search was included to identify relevant grey literature.

Eligibility criteria Papers were included if they added to substantive knowledge of ED crowding. Empirical studies, studies from the UK and studies of physical space were privileged in the review.

Results There is an established international literature on ED crowding. It suggests consistently that crowding has significant negative consequences. However, the literature offers limited practical help to practitioners for a number of reasons, such as a lack of shared definition and measurement of crowding and lack of evaluation of interventions. Many studies are single case studies from the USA.

Conclusions While current evidence is poor, this does not justify maintaining current practice which risks lives. Building up an evidence base is critical, but requires agreed definitions, measures and methods, which can be applied to systematic evaluation of plausible solutions.

  • Emergency care systems
  • emergency departments
  • emergency care systems
  • effieciency

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  • Funding The review derives from work undertaken at the Engineering Design Centre funded by the UK Engineering and Physical Sciences Research Council (EPSRC), grant reference EP/E001777/1. The views or opinions presented expressed in this paper are those of the authors and do not necessarily represent those of EPSRC, its associates or its sponsors. The role of the EPSRC was to provide funding for ZSM's post-doctoral position and partial funding for KB's PhD training.

  • Competing interests None.

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