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Validation and Impact of the 4 Hour Rule in Emergency Departments

Simpson Centre for Health Services Research, University of New South Wales
Project Added:
30 October 2014
Last updated:
30 October 2014

Examination of the external validity, effectiveness and outcomes of the Emergency Department four-hour rule as an intervention


The purpose of this partnership project is to assess the impact of the four-hour rule/National Emergency Access Target (NEAT) policy in reducing access block and its effects of Emergency Department (ED) overcrowding on patients before and after its implementation.

The large data linkage study will examine the trends and characteristics of patients under the policy in WA hospitals and compare them with similar patients not under the policy. This is a unique opportunity due to a natural experiment occurring in Australia with implications at the national and international levels.

The results of this research will assist the Agency for Clinical Innovation (ACI) in its objective to act as a catalyst for change and improvement in health-care service delivery in NSW. It will help ACI to continue to rebuild confidence in the community that the best evidence is used and implemented across NSW in consultation with relevant networks. It is also expected that this research will provide and consolidate evidence around the four hour rule policy intervention. This will assist the ACI Emergency Care Institute (ECI) to advocate strongly for the most appropriate process of intervention to be adopted in NSW and nationally with their close links with other agencies in NSW and nationally. 


  1. To evaluate the effectiveness and outcomes of the four-hour rule as an intervention and to identify the strategies implemented under this program in Western Australia.
  2. To assess the external validity of the intervention by replicating the analysis across states.
  3. To develop a long-term partnership to reduce the harmful effects of access block and ED overcrowding on patients and at the same time, to promote evidence based policy interventions for future research at the national and international level.


This project will allow for better targeted evidence based policies, avoid harmful effects from this intervention and allow modifications over time. It will compare ED patient outcomes associated with delays in EDs.

Project status

Project started:  1 January 2012.

Status: Implementation:

  • Data record linkage in process. 
  • The data analysis is ready for implementation.
  • Ethics and data linkage approvals have been completed. 
  • Planning for the initiative completed. 
  • Clinician/Consumer consultation has occurred.



  • Complete the ethic applications and data linkage process. This consists of creating linked data from existing admin datasets for all participating hospitals in NSW and WA.
  • Research protocols. Should have been completed and staff recruitment should be completed.
  • Basic analysis should be under way by the end 2014 in WA and NSW.
  • Bimonthly steering committee teleconferences are taking place.
  • An annual face-to-face meeting takes place during the Australasian College for Emergency Medicine conference in November/December each year. 
  • Complete publication plans according the research strategy and analysis plans are under completion and ready to start project outcome reporting.


  • By the end of the year we should have completed the basic analysis and reported on the quantitative research methodology and presentation of preliminary analysis to the respective partner organisations.
  • The basic data analysis will compare patients outcomes of patients delayed in the ED before (14 April 2007- 13 April 2009) during (14 April 2009- 13 April 2011) and after the implementation of the WA 4 hour policy (2011-2013) with other states.
  • At least two research papers documenting the basic methodology should be ready for publication.
  • The development of health service delivery recommendations will be done in collaboration with partner organizations. 
  • Continued peer-support engagement and model evaluation, analysis and reporting of data linkage baseline patient characteristics. Integration of additional data with already linked data.
  • Annual and monthly steering committee meetings will review the progress of the project. This will include annual reporting on key outcome measurements.


  • Adjusted analysis should have started and in progress in each participating states.
  • Advanced analysis such as multilevel analysis should be ready near completion.
  • The preparation of another draft publication of results should be ready or completed.
  • Potential confounders identified and controlled with advanced statistical techniques such as multilevel analysis, propensity scores and incidence rates of procedures using the most recent advances and concepts in data linkage epidemiology such as nested case-control studies.


  • Adjusted analysis should have been completed and implemented for each participating states.
  • Secondary analysis of data near completion.
  • Complete peer-reviewed publications and conference presentations.


The Australian Government announced plans for a Four-Hour National Access Target for Emergency Departments in 2009. This was ratified by the Council of Australian Governments (COAG) in February 2011. This means that ED patients, where clinically appropriate, must be admitted, referred for treatment or discharged within four hours. 

It has been progressively implemented across Australia since January 2011. The project has been extended until 31 December 2016.

One of the most important aims of the four-hour rule is to reduce the harmful effects of access block and ED overcrowding. 

This project will assess trends of patient outcomes before, during and after the four-hour rule/NEAT implementation in WA and then across Australia in order to evaluate the impact of the four-hour rule policy intervention and for the first time in Australia, make reliable comparisons across states.


  • Emergency Care Institute
  • Australasian College for Emergency Medicine
  • University of Western Australia
  • Queensland University of Technology
  • NSW Ministry of Health
  • WA Health Department
  • Australian National University / Canberra Hospital
  • NSW Ambulance
  • ACT Ambulance
  • WA Ambulance
  • Queensland Ambulance

Implementation sites

Hospitals participating in this initiative include: 


  • Fremantle Hospital
  • Joondalup Hospital
  • Princess Margaret Hospital
  • Royal Perth Hospital
  • Sir Charles Gairdiner Hospital


  • John Hunter Hospital
  • Liverpool Hospital
  • Mount Druitt Hospital
  • Prince of Wales Hospital
  • Royal North Shore Hospital
  • Westmead Hospital


  • Calvary Hospital 
  • Canberra Hospital


  • Gold Coast Hospital
  • Prince Charles Hospital
  • Redcliffe Hospital
  • Royal Brisbane and Women’s Hospital 

Lessons learnt

We have found it extremely helpful to initiate contact with the data custodian and ethics committee/representative, before beginning the application process, to discuss what is required from the outset to avoid any confusion. Due to the complexity of this project, we have found that making this initial contact and building rapport with the data custodian/ethics committee has allowed the process to run more smoothly. 


Dr Roberto Forero
Senior Research Fellow
Simpson Centre for Health Services Research
University of New South Wales
Phone: 02 9385 8986


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