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Hospital Episode Statistics

Hospital Episode Statistics (HES) processes over 125 million admitted patient, outpatient and accident and emergency records each year.

What is HES?

HES is a data warehouse containing details of all admissions, outpatient appointments and A&E attendances at NHS hospitals in England.

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.

It is a records-based system that covers all NHS trusts in England, including acute hospitals, primary care trusts and mental health trusts. HES information is stored as a large collection of separate records - one for each period of care - in a secure data warehouse.

We apply a strict statistical disclosure control in accordance with the HES protocol, to all published HES data. This suppresses small numbers to stop people identifying themselves and others, to ensures that patient confidentiality is maintained.

Who is HES for?

HES provides data for a wide range of healthcare analysis for the NHS, government and others including:

  • national bodies and regulators
  • local commissioning organisations
  • provider organisations
  • researchers and commercial healthcare bodies
  • patients, service users and carers.

What are the benefits of HES?

  • monitor trends and patterns in NHS hospital activity
  • assess effective delivery of care
  • support local service planning
  • provide the basis for national indicators of clinical quality
  • reveal health trends over time
  • inform patient choice
  • determine fair access to health care
  • develop, monitor and evaluate government policy
  • support NHS and parliamentary accountability

Why was HES developed?

HES was originally conceived in 1987 following a report on collection and use of hospital activity information published by a steering group chaired by Dame Edith Körner (1921-2000).

Before 1987, only a 10 per cent sample of admitted patient records were collected nationally. By comparison HES aims to collect a detailed record for each 'episode' of admitted patient care delivered in England, either by NHS hospitals or delivered in the independent sector but commissioned by the NHS.

Admitted patient care data is available for every financial year from 1989-90 onwards. During this period, the mechanisms for collecting the data have changed considerably, often in response to changes in the organisation of the NHS. For example, HES was once initially collated sub-nationally by regional health authorities. In 1996 these bodies were abolished and the NHS-Wide Clearing Service (NWCS) was set up to provide a means of transmitting the records. In 2006 this work was taken over by the Secondary Uses Service, which is run by the Health and Social Care Information Centre and the National Programme for IT.

Initially, data for HES publications was collected annually from provider submissions. After a number of years the frequency of collections increased to quarterly to allow analysis and investigation (these were not published) and a final annual publication was released at the end of the year. HES data is now collected monthly.