Guidance

Statement on revisions and corrections policy

Updated 7 May 2025

Applies to England

Scope

This document sets out how revisions and corrections to the Department of Health and Social Care’s statistical outputs, whether scheduled or not, take place in line with the Code of Practice for Official Statistics.

The Department of Health and Social Care (DHSC) aims to avoid the need for revisions to statistics but has put in place practices to make any necessary revisions and corrections transparent to users.

This policy applies to all staff with responsibility for the production and release of official statistics in DHSC including the Office for Health Improvement and Disparities (OHID).

Purpose and definition

Statistics are by their nature subject to error and uncertainty. Initial estimates are often systematically amended to reflect more complete information. Improvements in methodologies and systems can help to make revised series more accurate and useful.

Revisions and corrections are changes to any official statistic once it has been placed in the public domain.

Revisions and corrections

Our goal when handling revisions and corrections is to ensure transparency with our users by clearly explaining the reasons for changes, when to expect scheduled revisions, and outlining how unscheduled corrections will be communicated.

Decisions regarding any changes to published statistics will be made by the statistician responsible for the specific publication in consultation with our Head of Profession for Statistics, as appropriate.

Handling revisions and corrections

Our general approach to handling revisions and corrections is to:

• quickly identify the affected statistics and underlying data
• notify our Head of Profession for Statistics and communications teams about any significant revisions or corrections
• provide a clear explanation to users of the reason for changes where known and the details of the size and impact on the statistics
• publish revised or corrected statistics with a clear explanation as soon as practicable
• provide a direct comparison between the original and revised statistics
• engage with key users on proposed changes and explore options for maintaining a consistent time series, including any revisions of published data
• keep our users informed throughout the process

Scheduled revisions

Scheduled revisions are planned amendments to published statistics made to improve quality by incorporating additional data or information that were unavailable at the point of initial publication.

Scheduled revisions will be managed systematically, pre-announced and reflected in dissemination plans. Typically, such revisions will take place at the next scheduled publication of the series.

Scheduled revisions usually occur for the following reasons:

• as part of the normal release process - some highly aggregated series are first released in an incomplete state to meet the needs of users for timely information. More complete responses and analyses are released later
• seasonal adjustment, benchmarking or rebasing exercises - examples include regular updates to take account of further supplies of data or rebasing of an index to reflect new information
• changes to underlying methodology, sources or classifications
• incorporation of newly available or late data

If a statistical output, published by DHSC, has scheduled revisions, details about these revisions can be found on the collection page or within the commentary for that output.

Handling scheduled revisions

For scheduled revisions we will:

• pre-announce revisions to data where these are expected and scheduled. Typically, the publication of revised data would be timed to coincide with the latest release of related new data
• summarise the key impact nature and extent of revisions, typically at the national level. Where revisions impact on targets, this will be described
• provide explanations for individual revisions upon request - for example, to data originally reported by an individual NHS trust

Unscheduled corrections

Unscheduled corrections are amendments made to published statistics in response to the identification of errors following their initial publication. These are often caused by errors, unforeseen changes in methodology or changes to administrative or management systems which contribute data to official statistics. They can occur, for instance, at an unusual point in the revision cycle, or have an impact on the statistics that was not anticipated.

Unscheduled corrections can be caused by:

• errors in previously published data
• unforeseen changes in methodology
• unexpected acquisition of new data
• changes to any administrative or management systems that contribute data to official statistics

Handling unscheduled corrections

The general rule is to implement necessary corrections as soon as practicable.

Where results are affected by methodological changes, a description of the change will be given.

For corrections deemed by the Head of Profession for Statistics as ‘minor’, generally a replacement document will be issued, clearly marked with the date of the revision. This document should include:

• an explanation of the revision
• identifying the statistics that have been affected
• where possible an assessment of the size of the revision

For unscheduled corrections we will:

• explain corrections to statistics at the earliest opportunity and in a way that provides the most benefit to stakeholders
• issue corrections in an orderly way, for example with the next version of the amended statistic or, if appropriate, by way of an earlier release of data
• summarise the key impact, nature and extent of corrections, typically at the national level. Where corrections impact on targets, these will be described
• reserve the right not to publish some minor revisions if the resources required to issue them outweigh the benefits to stakeholders

Substantial revisions and corrections

Substantial revisions and corrections, whether scheduled or unscheduled, tend to have a more significant impact and fall outside the usual range of revisions normally associated with the statistics.

Handling substantial revisions and corrections

Decisions on the content, format and timing of releases that incorporate substantial revisions and corrections will be made by the Head of Profession for Statistics.

At the minimum, the statistical publication will be removed from the department’s website and replaced by a statement giving a reason for the revision and an expected timetable for the replacement statistics where known.