What will I get?

The main unit of recording is the Finished Consultant Episode (a period of admitted patient care under a consultant or allied healthcare professional within an NHS trust). This is not always the same as a single stay (spell) in hospital, because a patient may be transferred from one consultant to another during their stay. In these cases, there will be two or more episode records for the spell of treatment.

Diagnoses are currently coded according to the International Classification of Diseases, 10th Revision (ICD-10) and procedures and interventions according to the Office of Population, Censuses and Surveys: Classification of interventions and procedures, 4th Revision (OPCS-4).

HES records also contain the age of the patient and where they lived. There are further codes to identify the hospital, the length of time the patient stayed in hospital, and the specialty of the consultant who treated them. If the patient was on a waiting list (as opposed to being admitted in an emergency), the time they actually waited is also recorded.

Because it is sometimes possible to identify patients, access to the detailed records is strictly controlled. There are also restrictions on the nature of the tabulations (aggregated summaries) that can be released. These generally involve the suppression of small numbers, ie where it might be possible to infer the existence of a record for an individual known to the enquirer.