Introduction
Sometimes we need to update or change published statistics, analysis or data for various reasons.
Being clear, transparent, and consistent when publishing revisions and corrections of errors is important. It allows users to understand how and why our statistics, analysis or data are revised or corrected after publication, and how best to use them. This approach also ensures that we are following the Code of Practice for Statistics.
Revisions policy
Revisions are updates to previously published statistics, analysis or data. They improve the quality by incorporating better methods, or additional data that was not available when the statistics were first published.
Revisions should not be confused with the correction of errors; revisions are not published to correct a mistake.
Some revisions are necessary in order to balance timeliness with accuracy. For example, when speedy data is particularly important for users, initial estimates can sometimes be planned to be produced more quickly, but before the full data is available. These statistics would then be subsequently revised when more complete data is available.
Revisions may also be needed because of changes to methods or systems, including:
- new methods or improved methodology, such as changes in statistical methods, techniques, or systems; this also includes changes in concepts, definitions, and classifications
- rebasing – when a statistical index is rebased, it can be because either individual component items have been re-evaluated and the “weight” attributed to each has changed, or the reference period has been updated
Planned revisions and provisional estimates
In a number of releases (including the GDP/GVA and population and migration reports), revisions are expected and planned. To balance the often competing user needs of timeliness and accuracy, some releases will publish provisional estimates initially, and plan to revise these estimates after a period of time when additional (planned) data has been received, or further data quality processes have been carried out.
The revisions themselves, and the expected schedule of future revisions will be clearly signposted in the publication.
Correction of errors
Despite having quality control measures in place, mistakes may sometimes occur. Correction of errors are amendments that are made to published statistics in response to the identification of mistakes following their initial publication.
When a mistake is identified, the error is corrected as soon as possible in line with the Code of Practice for Statistics with limited exceptions. In a small number of cases, minor errors might not be corrected because of:
- the time scale (for example, the error occurred too long ago)
- the scale of the error (meaning that it would take too much resource for minimal improvements)
- it not being in the public interest to make the correction
Correction of errors are reported at the top of the affected release, including details of when and why the change was made.
Specific revisions and correction of errors policies
In some cases, Statistics Jersey publications may have specific revisions or correction policies that describe details for users on how revisions or corrections are managed. These will be described in the methods section of the particular report.