How we collect and process Hospital Episode Statistics (HES) data

HES extracts are taken from the Secondary Uses Service (SUS) database on a monthly basis, at pre-arranged dates during the year.

Each extract is cumulative and contains data submitted for the financial year so far, that is to say, month 1 will only contain the data submitted with an activity date in April, but month 6 will contain data submitted with an activity date from April to September. One of the reasons for this is that additional data may be needed to update patient records from earlier in the year. For example, an episode may potentially run for several months or an amendment may need to be made as clinical coding takes place on discharge.

HES data is a snapshot of data taken on the Reconciliation and Post-Reconciliation dates for each month. The SUS database is continually updated so the totals in SUS for a month will only match HES if they are queried on the day the snapshot is taken.

Annual refresh and final year data

At the end of each financial year we produce the official publication for that year. This is based on the March Post-Reconciliation submissions, also called Month 13.

While data relating to episodes and spells for a particular year can be amended and updated in SUS long after the year has passed, no further SUS updates are applied to HES which is fixed after the Post-Reconciliation Inclusion date for March.