Hospital Accident & Emergency Activity 2021-22

The ECDS publications focus on headline information about hospital attendances. Each annual publication includes a series of national tables and also provider-level breakdowns for some main areas.

Most data included in the published tables are aggregate counts of hospital activity. Where averages are published, e.g. median time spent in A&E, this data is clearly labelled stating how the data has been calculated.

The accuracy of ECDS 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:

HES A&E: CDS V6-2 Type 010 – Accident and Emergency CDS up to 2019-20

ECDS: CDS V6-2 Type 011 – Emergency Care CDS from 2020-21

NHS Digital has a well-developed data quality assurance process for the SUS and ECDS 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 Digital leads on the schema changes and consults the data suppliers about proposed changes.

Each month NHS Digital creates data quality dashboards available to NHS providers to show the completeness and validity of their data submissions to SUS. This helps to highlight any issues present in the provisional data allowing time for corrections to be made before the annual data is 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.

Data quality information for ECDS year to date is published at the same time as the provisional ECDS data, and also alongside annual publications.  These provide early analyses to compare data between providers (provider organisation, department type and month) four key fields: chief complaint, clinical Investigation, first diagnosis code and treatment code, published on the link below:

NHS Digital also publishes a regular Data Quality Maturity Index (DQMI) for providers across several datasets including ECDS. 

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

A&E HES data has been available from 2007-08 up until 2019-20 and during those early years data completeness was known to be an issue.

ECDS data has replaced HES A&E data for our patient level analytical reporting from April 2020. Whilst there is complete overall reporting coverage, data quality and completeness of certain submitted fields do vary within the data between providers reporting activity.

Users should note there was a reduction in attendances at each of the four Home Nation Emergency Departments between March 2020 and February 2021, during the COVID-19 outbreak compared with the previous year. The number of attendances began to rise again in March 2021 compared with March 2020, though this is due to March 2020 being low rather than March 2021 being high.

There are some definitional differences between ECDS data and MSitAE data. The main difference is that MSitAE data does not include attendances where the A&E appointment has been pre-arranged. Therefore, where ECDS is compared directly with MSitAE, planned follow-up attendances are excluded.

Codes are considered to be valid if they match to one of the NHS Data Model and Dictionary ECDS values for the specified field, or one of the values in the ECDS Technical Output Specification (TOS) and are considered invalid if they did not match one of the data dictionary or TOS values. Where a field has a null value it is considered invalid.

Collection of ECDS data is carried out on a daily basis throughout the financial year, with a provisional statistical publications being carried out on a monthly basis. A final annual refresh (AR) once the year end has passed is then published. The provisional monthly collection doesn't refresh the data back to the start of the financial year. However the annual refresh does, and therefore fields, such as the Health Resource Group (HRG), is populated for all of AR but not within the monthly data.

‘Month 13’ represents the provisional full year data and was published in June 2021. Hospital providers and the NHS Digital HES Data Quality team work to improve the quality and completeness of the data in order to produce the final AR data used in this report, as described in the Accuracy and Reliability Section above.

The table below shows the differences between the Month 13 provisional data and the final AR data are minimal.

Provisional ECDS data is submitted and published on a daily basis. The production of the underlying annual ECDS data sets takes several months after the reference period. The final submission deadline for NHS providers to send annual data to SUS is normally at the end of May, almost two months after that year has finished. It then takes approximately two months to produce the ECDS data set and a further month to complete publication production and data investigation.

In addition to annual data, NHS Digital also publishes provisional monthly HES and ECDS publications approximately six weeks after the reference period.

The final annual data includes some additional data cleaning and updated data for a couple of providers, compared to Month 13 data.

Users can misinterpret ECDS data as relating to numbers of patients, but care should be taken as the standard unit of ECDS data relates to hospital activity, not individuals.

In the case of A&E data, this is presented as attendances, which may include people attending more than once in the reporting period.

Separate collections of hospital statistics are undertaken by Northern Ireland, Scotland and Wales. There are a number of important differences between the countries in the way that data measures are collected and classified, and in the organisation of health and social services. For these reasons, any comparisons made between ECDS and other UK data should be treated with caution.

Hospital data for the other administrations can be found at:

• Northern Ireland – Hospital Statistics
• Scotland – Hospital Care
• Wales – Health and social care statistics

NHS England also publish other hospital activity data:. 

ECDS and similar statistics from the devolved administrations are used to contribute to World Health Organisation (WHO), Organisation for Economic Co-operation and Development (OECD) and Eurostat compendiums on health statistics.

HES A&E data is available from 2007-08 and was replaced as the source of patient level reported A&E data  by the ECDS in the 2020-21 reporting period. Changes to the figures over time need to be interpreted in the context of improvements in data quality and coverage (particularly in earlier years), improvements in coverage of independent sector activity (particularly from 2006-07) and changes in NHS practice.

Payment by Results (PbR) is a system whereby hospitals are paid for the number of patient treatments, known as activity, they perform and the complexity of these treatments. It was introduced in a phased way from 2003-04 onwards. In order to be paid correctly, care providers need to record the activity they perform and the clinical codes that outline the patients’ conditions and treatment. The introduction of PbR increased private sector involvement in the delivery of secondary care and brought about some changes in clinical practice (including some procedures occurring as outpatient appointments instead of hospital admissions). It is likely that these changes will have affected trends.

This has provided a major financial incentive for care providers to ensure all of the activity they perform, and the clinical coding is fully recorded. This improved recording of information captured within HES A&E data could be one of the factors leading to the reported activity increases.

Phased implementation of ECDS means that care should also be taken when comparing activity across the duration of the phased ECDS roll out also which commenced in October 2017. Since this point urgent and emergency care providers have been asked to submit data to the ECDS. Those that no longer submitted data via the A&E Commissioning Data Set (CDS 010) meant that their A&E data would no longer be automatically processed into Hospital Episode Statistics (HES) for that provider. In order to seek a continuity in the data during this transition period of ECDS, NHS Digital with guidance from nominated representatives from the Royal College of Emergency Medicine (RCEM) put in place a mapping process of reported activity within ECDS to A&E (CDS 010) to allow data to be populated for the providers who had switched to submitting ECDS so that data in the old HES A&E format could still be used for statistical releases until ECDS rollout was complete.

Whilst this phased rollout should not have impacted upon overall total counts of activity presented within the data, changes were expected in the composition of data from those trusts that submitted to ECDS and subsequently were mapped to the A&E Commissioning Data Set format. A key driver of the ECDS is to improve current clinical data quality and make the data that is captured compatible with other modern data sets. This has seen the adoption and utilisation of SNOMED Clinical Terminology in a number of fields within the data set enabling much more granular coding of activities relating to diagnosis and treatment for example from the much smaller pick lists present for such in HES A&E. To support in the monitoring, understanding and completeness of these new data fields, and particularly the use of SNOMED CT, NHS Digital has been working with key stakeholders to publish a range of data quality outputs through which the composition and content of these fields are expected to change over time. 

Care should be taken when comparing annual HES and ECDS data over time, as improvements in coverage in HES will contribute alongside growth from increased activity through the years. Although overall record counts in ECDS are comparable with HES A&E, it is know that some specific fields within ECDS are not complete, as providers adapt to submitting these new fields, and fields in the new SNOMED CT format to ECDS.

Extra care should be taken when looking at clinical data, as changes in NHS practices (such as the introduction of new procedures and interventions) can have an effect on changes through time.

Comparisons of Annual data for certain fields and reported activity is now no longer directly comparable since the phased introduction of the new Emergency Care Data Set commenced in October 2017. Since this point urgent and emergency care providers have been asked to submit data to the ECDS. Those that do this will no longer submit data via the A&E Commissioning Data Set (CDS 010), which means that their A&E data would no longer be automatically processed into Hospital Episode Statistics (HES) for that provider. In order to seek a continuity in the data during this transition period of ECDS, NHS Digital with guidance from nominated representatives from the Royal College of Emergency Medicine (RCEM) put in place a mapping process of reported activity within ECDS to A&E CDS to allow data to be populated for the providers who have switched to submitting ECDS so that data can still be used in this and other statistical releases.

Details of this mapping methodology can be requested by emailing [email protected]. All providers are now submitting to ECDS and since ECDS is used from 2020, the mapping is not applicable for 2021-22 data in this publication. Although HES A&E is still available, this dataset is no longer maintained and all of it is mapped from ECDS.

Additional detail may be found in the following methodological change notice paper published by NHS Digital

The change should not impact upon overall total counts of activity presented within the data. However, changes are expected in the composition of data from those trusts that have submitted to ECDS and have subsequently been mapped to the A&E Commissioning Data Set format for data from August 2017. A key driver of the ECDS is to improve current clinical data quality and make the data that is captured compatible with other modern data sets. Therefore, several codes that either represent clinical practice that no longer takes place in the A&E department or the coding adds no clinical value have been retired. Additionally, under SNOMED there is no ‘other’ code therefore it will no longer be possible for activity submitted by organisations via ECDS to be mapped to a small number of codes. The codes and fields identified as being affected are listed in the methodological change paper referenced earlier. Comparisons across time of activity before and after the 1st October 2017 of activity using these codes or using other codes within these specific fields therefore may not be comparable.

The first CDS010 based A&E submission from providers in England was for the 2007-08 financial year; these reports were classed as experimental until 2012-13.

The phased rollout of ECDS submissions from providers in England commenced in October 2017 and a combined mapped data asset was created to cover the period of the rollout. Please see detail in the comparisons with Annual HES section above. ECDS replaced CDS010 as the source for production of NHS Digital patient level A&E data from April 2020. As this represents the first year that ECDS data has been utilised in its native structure without retrospective mapping metrics and measures derived using ECDS that were not possible in the previous HES A&E data structure, these have been classified as experimental statistics within this report. 

Experimental Statistics should be used with caution. Experimental statistics are new official statistics undergoing evaluation.

They are published in order to involve users and stakeholders in their development and as a means to build in quality at an early stage. More information about experimental statistics can be found on the UK Statistics Authority website.

The Organisation Data Service (ODS) is responsible for the publication of all organisation and practitioner codes and national policy and standards with regard to the majority of organisation codes.

More information about the ODS and changes to organisation codes and geographical boundaries is available. 

As ECDS is such a rich source of data it is not possible to publish aggregate tables covering all permutations of possible analysis. Underlying ECDS data is also made available to facilitate further analysis that is of direct relevance to users. There are no restrictions to accessing the published data.

Providers have the opportunity to submit data daily, which is centrally assessed for data quality issues. These are reported back to providers in order to give an opportunity to address these issues found by taking snapshots and monitoring different quality metrics at different points in time throughout the year. The data used in this report is finalised for the full financial year, providers having a number of weeks after 31 March in the reporting period to review and rectify issues. Any issues remaining after that point are noted where applicable in accompanying data quality outputs when the data is published on NHS Digital’s website. No additional attempts are made to amend or resubmit data for inclusion in this asset after the data is finalised.

Users of the data and this publication are encouraged to report and feedback their views and suggestions. We have a dedicated e-mail address [email protected], for users to e-mail their queries or concerns and if anything is identified as being unclear, we address that as soon as we possibly can.

The production of ECDS data is a secondary use of data collected during the care of patients in the NHS and submitted for NHS Providers to be paid for the care they deliver. Therefore, ECDS does not incur additional costs or burden on the providers of the data.

Although certain information is considered especially sensitive, all information about someone's health and the care they are given must be treated confidentially and in accordance with legislation and NHS Digital protocols at all times.

There are a limited number of people authorised to have access to the record level data, all of whom must adhere to the written protocol issued by NHS Digital on the dissemination of ECDS data. For example, guidance is given on handling the very small numbers that sometimes occur in tables to reduce the risk that local knowledge could enable the identification of either a patient or clinician.

ECDS is a record level data warehouse and it contains information that could (if it was made freely available) potentially identify patients or the consultant teams treating them. In some cases, record level data may be provided for medical / health care research purposes. For example, data is likely to be required by the Care Quality Commission and other such bodies. The information may be given following a stringent application procedure, where the project can justify the need and where aggregated data will not suffice. Any request involving sensitive information, or where there may be potential for identification of an individual, is referred to the appropriate governance committee. NHS Digital publishes a quarterly register of data releases, which includes releases of ECDS data.

ECDS data is stored to strict standards: a system level security protocol is in place. This details the security standards that are in place to ensure data is secure and only accessed by authorised users.