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Waiting times in emergency departments: exploring the factors associated with longer patient waits for emergency care in England using routinely collected daily data
  1. Steven Paling,
  2. Jennifer Lambert,
  3. Jasper Clouting,
  4. Júlia González-Esquerré,
  5. Toby Auterson
  1. Economics team, NHS Improvement, London, UK
  1. Correspondence to Steven Paling, Economics team, NHS Improvement, London SE1 8UG, UK; steven.paling{at}


Background Long lengths of stay (also called waiting times) in emergency departments (EDs) are associated with higher patient mortality and worse outcomes.

Objective To add to the literature using high-frequency data from a large number of hospitals to analyse factors associated with long waiting times, including exploring non-linearities for 'tipping points'.

Methods Multivariate ordinary least squares regressions with fixed effects were used to analyse factors associated with the proportion of patients in EDs in England waiting more than 4 hours to be seen, treated and admitted or discharged. Daily situation reports (Sitrep), hospital episode statistics and electronic staffing records data over 90 days between December 2016 and February 2017 were used for all 138 English NHS healthcare providers with a major ED.

Results Higher inpatient bed occupancy was correlated with longer ED waiting times, with a non-linear association. In a full hospital, with 100% bed occupancy, the proportion of patients who remained in the ED for more than 4 hours was 9 percentage points higher (95% CI 7.5% to 11.1%) than with an 85% occupancy level. For each percentage point change in the following factors, the proportion of ED stays over 4 hours also increased: more inpatients with hospital length of stay over 21 days (0.07%, 95% CI 0.008% to 0.13%); higher emergency admissions (0.08%, 95% CI 0.06% to 0.10%); and lower discharges relative to admissions on the same day (0.04%, 95% CI 0.02% to 0.06%), the following day (0.05%, 95% CI 0.03% to 0.06%) and at 2 days (0.05%, 95% CI 0.04% to 0.07%).

Conclusions These results suggest that tackling patient flow and capacity in the wider hospital, particularly very high bed occupancy levels and patient discharge, is important to reduce ED waiting times and improve patient outcomes.

  • research
  • operational
  • performance improvement
  • emergency departments
  • emergency care systems
  • crowding

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  • Contributors SP, JL, JC, JG-E and TA were all responsible for the conception and design of the study and interpretation of the data analysis. JL, JC and JG-E conducted the data collection and analysis. SP, JL, JC and JG-E were part of the writing committee. SP performed the literature review. TA reviewed the writing and analysis and provided comments. SP is guarantor.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Patient consent for publication Not required.

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

  • Data availability statement Daily winter Sitrep data are available in a public, open access repository: Hospital episode statistics may be obtained from the NHS Digital Data Access Request Service ( for users who meet their data governance standards. More information is available here:

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