What is the data?

HES is a records based system that covers all NHS trusts in England, including acute hospitals, primary care trusts and mental health trusts. HES records also include care provided to NHS patients by the independent sector, including that taking place in treatment centres, and care given to private patients in NHS hospitals.

HES information is stored as a large collection of separate records - one for each period of care - in a secure data warehouse. Each HES record contains a wide range of information about an individual patient admitted to an NHS hospital. For example:

• clinical information about diagnoses and operations
• information about the patient, such as age group, gender and ethnic category
• administrative information, such as time waited and date of admission
• geographical information on where the patient was treated and the area in which they lived.