What counts as a major change and what counts as minor?

A major change, in the Eurostat manual, encompasses all changes at section level, including changing of headings, division and group level changes, including changing of headings, restructuring within groups, and mergers and splits of classes. The manual states that definition at the start of the passage on main changes, before listing the major changes section by section. The distinction decides what is listed in the changelog passage. It does not decide whether a change matters for reading a statistic, because a minor change can still affect the scope of a class.

What is listed as major, and what is left out?

Major changes are listed section by section, from Section A through Section V in the new lettering, with a paragraph for each section that had a major change. Section B for mining and quarrying, for example, is listed with the statement that there have been no major changes to that section. That statement is itself part of the major changes record: it tells the reader that no change meeting the major definition was made in that section, while leaving open the possibility of minor changes inside it. A reader who needs to compare mining statistics across versions must therefore still check the notes and the correspondence table for the classes in Section B, because a minor heading change or a partial transfer could affect a class even where no major change is listed.

The major list includes changes that do not change the total count, as well as changes that do. A restructuring within a group, for example, can change the groups and classes inside a division without changing the total number of classes in the classification by the same amount, because creations and removals can offset each other. A renaming at section level, such as the renaming of Section S from arts, entertainment and recreation to arts, sports and recreation, is a major change by definition, because it is a heading change at section level, even though it does not change the count. The major list must therefore be read as a list of structural and heading changes at the higher levels, plus splits and mergers at class level, not as a list of changes that altered the totals.

Category in the manual definition	Examples listed as major or minor
Major: section heading change	Section S heading change, Section J split
Major: division and group heading change	Group restructurings in manufacturing and trade
Major: restructuring within groups	Restructuring of group 25.6, division 96
Major: merger or split of classes	Mergers in trade, splits in health and wood
Minor: group and class heading change	Heading changes not listed in the major passage
Minor: renumbering, recoding, partial transfer	Content moved in part between classes

Why does the manual separate major and minor changes?

The manual separates major and minor changes to keep the changelog readable while preserving the detailed record elsewhere. The major changes passage is a summary of the main changes, as the Eurostat overview page describes it: a summary of the main changes is given in section 4 of the introductory guidelines. The detailed record is in the correspondence tables and the explanatory notes, which cover every class, whether its change was major or minor. The separation therefore does not hide minor changes. It places them in the detailed sources, where they can be checked class by class, rather than in the summary, where they would obscure the main structural changes.

The separation also reflects the design of the update. Eurostat states that efforts were made to maintain the structure in areas that did not explicitly require change, and the manual states that the overall characteristics were not changed. Minor changes are the small adjustments that keep the classification consistent while the structure is maintained: a heading clarified, a code renumbered after a split, a part of the content of one class transferred to another. Those adjustments matter for a class, but they do not change the structure at section, division or group level, and they are therefore not listed as major. A reader who treats absence from the major list as proof of no change will misread those adjustments.

How is a minor change checked?

A renumbering or recoding is checked by the same method. The class code in the new version must be looked up in the structure table for the new version, and the old code must be looked up in the structure table for the old version. The correspondence table then shows whether the renumbered class has the same scope, or whether the renumbering accompanied a change in scope. A code that changed only in number, with the same heading and the same note, is a recoding. A code that changed in number and in heading or note is a recoding with a content change, and the table type and the notes will show the difference.

What does the major and minor distinction not decide?

The distinction does not decide whether a change affects a particular statistic, and it does not decide an entry for a business. A minor change to a class that is heavily used in a statistic can have a larger effect on a series than a major change to a class that is rarely used. The effect depends on the use of the class in the statistic, not on the label major or minor in the changelog. A reader who needs to know the effect must check the correspondence table and the notes for the classes used in the statistic, and must check whether backcasting or double reporting is available for the domain. The institute or register that holds the record confirms an entry, using the notes and the rules for the version concerned.

Read the major changes definition at the start of the manual passage, read the section passages for the major changes, and confirm any entry with the national statistical institute or the business register that holds the record.