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Understanding variation in rates of ambulance service ‘non-conveyance of patients to an emergency department’ (VAN)


Ambulance services have increased their use of alternatives to transporting patients to an emergency department (ED) in order to help manage demand, provide a clinically appropriate service for patients and contribute to reducing unnecessary use of EDs and emergency beds. This is often referred as ‘non conveyance’. Alternatives to transporting patients to an ED include the provision of telephone advice rather than dispatching a vehicle (‘hear and treat’), treatment at the scene (‘see and treat’) and transport to other facilities such as a walk in centre (‘see and convey elsewhere’). There is considerable variation in the rates of different types of non-conveyance, and in non-conveyance overall, between ambulance services in England.

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Understanding the reasons for variation between services can help to identify ways of improving service delivery across all ambulance services.

Aims of the study

  1. To identify the determinants of variation between and within ambulance services for three different types of non-conveyance: ‘hear and treat’, ‘see and treat’ and ‘see and convey elsewhere’.
  2. To identify the determinants of variation between and within ambulance services in potentially inappropriate non-conveyance for three different types of non-conveyance.
  3. To explore organisational variation in the provision of ‘hear and treat’ in three ambulance services.
  4. To understand variation between and within ambulance services in three different types of non-conveyance rates for respiratory problems.

Work Packages

WP1 Identifying factors affecting variation in rates of non-conveyance and potentially inappropriate non-conveyance

We will undertake a qualitative interview study with three key stakeholder groups; service providers, paramedics and commissioners. We will identify perceived determinants of each of the three different types of non-conveyance (‘hear and treat’, ‘see and treat’, ‘see and convey elsewhere’) and potentially inappropriate non-conveyance for ambulance services in England.

WP2 Testing factors affecting variation between and within ambulance services


We will obtain one month of routine Computer Aided Dispatch (CAD) call data from ambulance services to identify determinants of each type of non-conveyance. The factors we will test will relate to three levels: patient characteristics, crew characteristics and organisational characteristics.

WP3 Factors affecting variation in potentially inappropriate non-conveyance rates

We will repeat WP2 to assess the determinants of re-contact rates within 24 hours for two types of non-conveyance; ‘hear and treat’ and ‘see and treat’.

Additionally, using data from the ongoing NIHR Applied Research Programme PhOEBE, which is linking 6 months of data from two ambulance services with ONS and HES data, we will identify the mortality rate, hospitalisation rate, and ED attendance rate for the three types of non-conveyance.

WP4 In-depth exploration of variation in non-conveyance practices

There is a lack of evidence about variation in ‘hear and treat’ non-conveyance. We will therefore focus on this type of non-conveyance in three ambulance services with varied practice, undertaking interviews with call takers, clinical supervisors and managers as well as non-participant observation of two key processes; making the decision to offer ‘hear and treat’ and offering the ‘hear and treat’ advice.

Research Team

Professor Alicia O’Cathain (Lead investigator/WP2 lead)
Dr Emma Knowles (Project manager/WP1 lead)
Joanne Coster (WP3 lead)
Dr Rachel O’Hara (WP4 lead)
Lindsey Bishop-Edwards
Dr Richard Jacques
Janette Turner
Tony Stone
Maggie Marsh (PPI representative)

Cathryn James (Yorkshire Ambulance Service)
Professor Niro Siriwardena (University of Lincoln)
Professor Julia Williams (University of Hertfordshire)


Health Services and Delivery Research Programme

For further details about this research, please contact Richard Campbell, study administrator at

This project has now ended. The report and the plain and scientific summaries can be found on the right-hand side of this webpage.