Hospital Outpatient Activity 2024-25

The accuracy of HES data is the responsibility of the NHS providers who submit the data to the Secondary Uses Service (SUS). This data is required to be accurate to enable providers to be correctly paid for the activity they undertake.

SUS is the single, comprehensive repository for healthcare data in England which enables a range of reporting and analyses to support the NHS in the delivery of healthcare services.

When a patient or service user is treated or cared for, information is collected which supports their treatment. This information is also useful to commissioners and providers of NHS-funded care for 'secondary' purposes - purposes other than direct or 'primary' clinical care - such as:

• healthcare planning
• commissioning of services
• national tariff reimbursement
• development of national policy

SUS is a secure data warehouse that stores this patient-level information in line with national standards and applies complex derivations which support national tariff policy and secondary analysis. 

A list of mandatory and optional fields for submission in in the Commissioning Data Set (CDS) is provided within the NHS Model and Data Dictionary:

Outpatients CDS V6-2 Type 020 – Outpatients CDS

NHS England has a well-developed data quality assurance process for the SUS and HES data. It uses an xml schema to ensure some standardisation of the data received. The use of the schema means that the data set has to meet certain validation rules before it can be submitted to SUS. NHS England leads on the schema changes and consults the data suppliers about proposed changes.

Each month, NHS England create data quality dashboards available to NHS providers to show the completeness and validity of their data submissions to SUS. These help to highlight any issues present in the provisional data allowing time for corrections to be made before the annual data are submitted.

An external auditor, acting on behalf of the Department of Health (DH), audits the data submitted to SUS to ensure NHS providers are being correctly paid by Payment by Results (PbR) for the care they provide.

NHS England validates and cleans the HES extract and derives new items. The team discusses data quality issues with the information leads in hospital trusts who are responsible for submitting data. The roles and responsibilities within NHS England are clear for the purposes of data quality assurance, to assess the quality of data received against published standards and report the results.

Data quality information for each year to date HES dataset is published alongside the provisional year to date HES data, and also alongside annual publications. These specify known data quality issues each year and where a trust has a known shortfall of secondary diagnoses. The statisticians can only check the validity and format of the data and not whether they are accurate, as accuracy checking requires a level of audit capacity and capability which NHS England does not currently possess.

Further information about HES data quality is available here.

NHS England also publishes an annual report, The Quality of Nationally Submitted Health and Social Care Data, which highlights issues around the recording of the underlying data that is used for HES, as well as examples of good and poor practice, and a regular Data Quality Maturity Index (DQMI) for providers across several datasets including HES. 

The HES Outpatient 2024-25 dataset includes records of patient appointments collected from 1,356 providers in England.

Table 1 shows the count and percentage of certain key fields in the outpatient data set that contain valid values in 2023-24 and 2024-25.

Table 1: Data completeness for outpatient HES, 2023-24 and 2024-25

Source: NHS England

*The denominator used to calculate the percentage of valid diagnosis and procedure records was the number of attended appointments as the record should not be recorded on non-attended appointments.

Detailed information about data quality of data items, and completeness of provider data submissions is available.

Outpatient HES data has been available since 2003-04 and during those early years data completeness was known to be an issue.

Records submitted into the Outpatients dataset are not required to populate diagnosis or procedure fields. As a result these fields will often show NULL values.

HES data are processed from SUS on a monthly basis throughout the financial year, with a final Annual Refresh (AR) once the year end has passed. Each monthly collection refreshes data back to the start of the financial year.

Providers are no longer routinely offered the opportunity to re-submit data for HES after the submission deadline (top-up files), which was approved by partners on the Data Quality Steering Group (DQSG).  The facility to re-submit top-up data is, however, available, on an exception basis, for those cases where resubmission would allow a significant improvement in the data. This has enabled us to commit to publishing Annual data earlier than for previous years.

Whilst NHS England encourages providers to submit all relevant data, some providers only submit outpatient records for those appointments that were actually attended. Care should therefore be exercised when looking at the number of appointments that were labelled as cancelled or did not attend as these are likely to be an undercount of the actual position.

Table 2 shows the number of attended and did not attend appointments in month 13 and at annual refresh.

Table 2: Comparing month 13 and annual refresh data, 2024-25

Table 3 shows the change from the Months 12 and 13 provisional data and the final annual refresh data.

Table 3: Monthly variation in submitted records, 2024-25

Source: NHS England