Hospital Episode Statistics Data Dictionary

The HES Data Dictionary is a Technical Output Specification document containing detailed information of all the fields available in HES for:

• admitted patients
• outpatients
• accident and emergency
• critical care
• HES ONS linked mortality data sets that are collected and used in HES

This document is fundamental for anyone using HES data, where users can see which fields are available to use and the associated definition, format, availability, and valid values for these fields.

Details of fields that are cleaned following submission, or derived are also included. Known data item issues are also available from this document.

The fields within HES are either based on or derived from the NHS Data Model and Dictionary. This covers all data sets and data items used in the NHS, not just those from which HES is extracted. It is developed and maintained by the NHS Data Model and Dictionary Service at NHS Digital.

Please send any data dictionary queries to [email protected] referencing HES Data Dictionaries in the subject.

The HES Processing and HES Data Quality includes the provider mapping and duplicate removal methodological documentation and is currently being updated.