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National Clinical Analysis and Specialised Applications Team

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Hospital Episode Statistics (HES)


What is HES?

Hospital Episode Statistics (HES) is a records-based system that covers all NHS trusts in England, including acute hospitals, primary care trusts and mental health trusts and contains details of all admissions, outpatient appointments and A & E attendances.

This data is collected during a patient's time at hospital and is submitted to allow hospitals to be paid for the care they deliver. HES data is designed to enable secondary use, that is use for non-clinical purposes, of this administrative data.

What is Collected in HES?

The data collected relate to:

  • Patients - including age, sex, ethnicity and location of residence
  • Clinical details - including diagnoses, operative procedures, consultant and specialty.
  • Administrative details - such as NHS trust, GP, admission and discharge date and method and referrer


As HES data is very complex, any standard report can only show basic information such as number of episodes with a certain primary diagnosis or primary procedure. As might be expected, patients often present with more than one diagnosis or have more than one procedure performed. We can provide analysis based on combinations of procedures and diagnoses as required. We can also provide analysis at provider level and residence level, including mapping using GIS. This has proved invaluable in the past for clients interested in service re-design and re-location of services.

Episodes, Spells & Pathways

The basic counting unit for calculation in admitted care HES data is the finished consultant episode (FCE). This is the total time a patient spends under the care of an individual consultant. FCEs can be aggregated into spells which then gives the total time a patient spends in one hospital (From Admission to Discharge)

The Information Centre holds the HES data as a series of FCEs and does not currently have any plans to aggregate them into spells. NATCANSAT feel that there are many advantages to providing data at spell-based level such as being able to calculate the complete time that a patient undergoing a certain procedure remains in hospital. For instance, a patient undergoing a hip replacement may be admitted under an orthopaedic consultant for their procedure but then be transferred to another consultant for a period of rehabilitation. By looking at FCEs, only the time under the orthopaedic consultant would be taken into account whereas using spells, the entire time from admission to discharge would be used.

NATCANSAT have also developed a methodology to link together spells between Trusts. For example, a patient gets admitted to one Trust to have a scan carried out, and needs to be immediately referred to a tertiary centre for a specialist operation. All the time intervals that took place can be investigated by joining Episode into Spells, then Spells into Continuous Patient Pathways.


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