Standard

Statement on revisions for official statistics

Updated 25 October 2023

Applies to England

Introduction

Practice T3.9 of the UK Statistics Authority Code of Practice for Statistics states:

Scheduled revisions or unscheduled corrections to the statistics and data should be released as soon as practicable. The changes should be handled transparently in line with a published policy.

In accordance with the practices of the code, this statement details Ofsted’s policy on revisions and our commitment to explain these alongside our statistics.

When and why we make revisions

A revision is defined as any change to official statistics in the public domain.

Ofsted aims to avoid the need for revisions to statistical publications unless they are absolutely necessary or planned, such as in the case of provisional statistics.

Processes are in place to minimise the number and scale of any revisions.

We publish revisions to our statistical publications:

• if we receive subsequent information or data that changes our understanding of previous periods (for example, when inspection grades are published after provisional statistics for the reporting period have been released)
• to correct data if there are errors

Planned revisions

Some of our statistical publications include a first release based on provisional data, followed by a second release based on revised or final data. Our annual releases, for example, may include updated data for the previous year where some outcomes were not available at the time of first publication.

These are planned revisions and occur as part of the normal release practice. The timing of our statistical publications is designed to minimise the need for significant revisions because of changes to the information held.

The same rationale and processes apply to all releases where planned revisions are made. However, information can change due to unforeseen circumstances, and subsequent revisions may be needed. In these instances, we inform users of the upcoming revision via GOV.UK.

The following official statistics publications are subject to planned revisions:

• childcare providers and inspections (2 releases annually)
• children’s social care in England (annual release)
• fostering in England (annual release)
• further education and skills inspections and outcomes (annual release)
• initial teacher education inspections and outcomes (annual release)
• non-association independent schools inspections and outcomes (annual release)
• state-funded schools inspections and outcomes (2 releases annually)

The reasons for, and impact of, changes between provisional and revised statistics will be explained in the subsequent statistics release. A valid reason for change is when we need to update figures to include the outcomes of those inspections carried out during the period, but where the inspection report had not been published at the time of compiling the provisional statistics

Changes in source systems or methodology

If we plan major changes to the data, or propose changes in statistical methodology, definitions or categories, we will consult with users where possible.

We normally announce methodological changes and improvements in advance, as they may result in revisions to published data. We will provide explanations with revised data, where possible, to avoid breaks in the published time series.

Errors

Occasionally, errors may occur in our statistical processes. We do everything we can, including constant review of our processes, to minimise these errors. If an error is detected, the chief statistician will consider:

• the impact on users and their uses, for example, whether it is a headline figure or major component
• the size of the correction, particularly relative to any stated levels of accuracy
• the impact on the meaning/interpretation of the statistics – that is whether it alters the main message of the statistics or any likely use

Valid reasons for correcting errors include:

• correcting any figure that was wrong due to typographical or similar
• correcting any figure that was wrong due to errors in the compilation of the statistics

We will amend minor errors straight away or correct them in the next statistical release, depending on their nature. If errors are considered to be major, Ofsted will issue a statement on GOV.UK and contact known users.

Handling of revisions

Our policy on handling revisions to statistical publications is to be open and transparent with users about:

• the need for revisions
• how and when to expect standard, scheduled revisions
• the processes for communicating and publishing other revisions

The official statistics outputs, which are subject to scheduled revisions, will contain a link to this policy.

We announce revisions through provisional statistics releases on GOV.UK. We will explain the impact of revisions when we release the final data. When making a revision to a publication we will give details about the revision on the release page on GOV.UK. If you would like to be notified about any of our releases, including any revisions made, you can sign up for email updates.

We will announce in advance the date for the release of revised figures or our intention to change the methodology. We will publish revised figures on the pre-announced date and these will follow the same principles as the original information.

Jason Bradbury
Head of Profession for Statistics
Ofsted
October 2023