Guidance

Statement on revision policy

Updated 1 October 2021

Applies to England

Scope of document

This document sets out how revisions 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 published in February 2018.

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 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 of revisions

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.

Definitions

A revision is a change to any official statistic once it has been placed in the public domain, whether through a printed document or electronically.

Policy

Scheduled revisions

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:

• where they form a normal part of the release process for a given series. This is common in highly aggregated series which are often first released in a less-than-complete state in order to meet the needs of users for timely information. Results based on more complete responses and analyses are then released at a later date

• as a result of seasonal adjustment, benchmarking or rebasing exercises. Examples include regular updates to take account of further supplies of data or rebasing of an index to take account of new information

• changes – for example, to the underlying methodology, sources, classifications or local authority boundaries

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.

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
• make available on request explanations for individual revisions, for example to data originally reported by an individual NHS trust

Unscheduled revisions

Unscheduled revisions are those that do not fit into the managed pattern of revisions normally associated with the statistics in questions. They can occur, for instance, at an unusual point in the revision cycle, or have an impact on the statistics that was not anticipated. They can be caused, for example, by errors, unforeseen changes in methodology, unexpected acquisition of new data, or by the effects of changes that may be made, for both statistical and non-statistical reasons, to any administrative or management systems that contribute data to official statistics.

The general rule is that when revisions are needed, they will take place as soon as practicable. For those revisions deemed by the Head of Profession to be ‘minor’, generally a replacement document will be issued clearly marked by the date of the revision with an explanation of the revision, identifying the statistics that have been affected and where possible an assessment of the size of the revision. Where results are affected by methodological changes, a description of the change will be given.

For unscheduled revisions 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

Substantial revisions, whether scheduled or not, are those that lie outside the range of revisions normally associated with the statistics in question and that tend, therefore, to have a more significant impact. Decisions on the content, format and timing of releases that incorporate substantial revisions will be made by the Head of Profession. At the minimum, the statistics publication will be removed from the department’s website and replaced by a statement giving a reason for the revision and a timetable for the replacement statistics, at the same time placing a notice on the UK Nationals Statistics publication hub.