What is renumbering without a content change?

Renumbering without a content change happens when a category keeps its activities and its explanatory note, but receives a new identifier because the structure around it moved. The clearest case in NACE Rev. 2.1 is the shift of section letters after the split of the old Section J. Sections that followed the old Section J moved one letter forward, so a heading can carry a new letter while describing the same activities. The identifier changed. The content did not.

A reader who treats every new identifier as a new meaning will misread the whole of the classification after the letter shift, and will join series incorrectly across the change.

How does a letter shift work?

Sections are identified by one letter. Divisions, groups and classes sit inside a section and carry numeric identifiers. When a new section is inserted, or an old section is split into two, the letters after the insertion point shift to keep the sequence intact. The numeric identifiers inside each shifted section can stay the same, because they describe the position inside the section, not the section itself. The full identifier therefore changes at the letter, while the lower levels stay recognisable. Eurostat states that the former Section J was split into Section J and Section K, and the sections that followed shifted one letter as a result. That statement describes the mechanism. The correspondence tables and the notes show, heading by heading, whether content moved as well.

Element	Before the shift	After the shift	Content
Section letter	Earlier letter	One letter later	Same section content, unless restructured
Division number	Two digits	Same two digits	Same, unless restructured
Group number	Three digits	Same three digits	Same, unless restructured
Class number	Four digits	Same four digits	Same, unless restructured

The table above shows the shape of a pure letter shift. It is an illustration of the mechanism, not a claim about any particular heading. A heading that also gained or lost activities is not a pure renumbering, and its correspondence row will show the movement.

How is renumbering distinguished from a move?

The distinction is made in two documents. The correspondence table shows whether activities move between headings. In a pure renumbering, the row is one to one, with the same lower level numbers and a changed section letter, and no other heading feeds into or draws from the heading. The explanatory note shows whether the content matches. In a pure renumbering, the inclusions and exclusions in the new note match those in the old note. If either document shows a difference, the change is more than renumbering. A reader should check both documents, because a table row alone cannot show a change in the wording of a note, and a note alone cannot show that another heading also points to the same new heading.

Why does renumbering cause errors in datasets?

Datasets often store the identifier without the version. A code copied from a table compiled under NACE Rev. 2 and a code copied from a table compiled under NACE Rev. 2.1 can look alike and mean different things, or look different and mean the same thing, depending on where the letter shift falls. The CSO in Ireland notes that correspondence tables present detailed information on classes for which some activities move, and that the Section J split is the most obvious structural change. The same caution applies to renumbering: a bare identifier, without its version and its section letter read in context, is ambiguous. Datasets should state the version beside the code. Where a dataset does not state the version, the reader should ask the publisher which version was used before comparing figures across years.

What does renumbering not decide?

Renumbering decides nothing about a specific business. The legislation only applies to the use of the classification for statistical purposes, as the EUR-Lex summary states, and it does not oblige member states to collect, publish or supply data. A new identifier does not create a new obligation, remove an old one, or change how an activity is taxed, licensed or funded. Those questions belong to the authority or register that holds the record. The classification change is a change in how statistics are grouped. The entry for a specific business is confirmed with the national statistical institute or the business register that holds the record, with the version stated beside the code.

A changed letter with unchanged numbers and an unchanged note is a new address for the same heading, and the table row plus the note together prove that nothing else moved.