What stayed the same in Rev. 2.1?

Much of NACE stayed the same in Rev. 2.1. The Eurostat manual states that the overall characteristics of NACE have not been changed through Update 1, and that the update strikes a balance between the level of disaggregation requested by main users and the workload in statistical offices. Stability was therefore a stated aim of the update, alongside the integration of new concepts, and the correspondence figures show its scale: 354 of the 615 classes in NACE Rev. 2 correspond exactly to one class in NACE Rev. 2.1 and vice versa.

What stayed the same in structure?

The four level hierarchy stayed the same. Sections, divisions, groups and classes, with the same identifier forms, one letter, two digits, three digits and four digits, are the structure of both versions. The regulation framework stayed the same: Regulation (EC) No 1893/2006 as amended by Commission Delegated Regulation (EU) 2023/137, with the same statistical purposes limit. The classification rules in the introductory guidelines stayed the same in their overall approach, with revised rules for outsourcing and new treatment for intermediation as the stated conceptual changes, rather than a replacement of the rules as a whole. The explanatory notes and correspondence tables remained the supporting documents, with the index added as a new feature of the notes in the new version.

Sections A to I kept their letters and, in substance, their headings, with the heading change at Section G for the removal of repair words, and the split at Section J, as the exceptions. The manual Table 4 shows those sections unchanged in the comparison, and the passages for Sections A to I list changes inside them, such as the merger in agriculture and the splits in manufacturing, while the section headings themselves stayed the same. A reader who works at section level for those sections will therefore find familiar headings, while a reader who works at class level inside them must still check the class changes listed for the section.

What stayed the same	Source statement
Four level hierarchy and identifier forms	EUR-Lex summary, manual structure passage
Overall characteristics	Manual: not changed through Update 1
Structure where no change was required	Eurostat overview: efforts made to maintain it
One to one classes	Manual correspondence passage: 354 classes
Statistical purposes limit	EUR-Lex summary, both instruments

Which section had no major change?

Other sections also contain areas that did not change, even where the section as a whole had major changes elsewhere. The manual states that efforts were made to maintain the structure in all areas that did not explicitly require change. A division inside a changed section may therefore be unchanged, and a group inside a changed division may be unchanged. The correspondence type for each class shows whether it changed: a one to one correspondence means that the class corresponds exactly to one class in the other version, while the other three types mean that the class was involved in a merger, a split, or a many to many relationship. The class level check, not the section level summary, decides whether a particular class stayed the same.

Why was stability an aim of the update?

Stability was an aim because classifications must support comparison over time. The manual states that intervals between updates must not be too long, since relevance diminishes, nor too short, since comparability over time is adversely affected, and that any update with structural changes leads to breaks in time series. Maintaining the structure where no change was explicitly required reduces the number of breaks, and makes backcasting and double reporting more manageable. The overview page lists plans for backcasting and double reporting as part of the roll out, and those plans depend on a large part of the classification remaining comparable. Stability is therefore not inertia. It is a design choice that preserves the usefulness of the statistics that depend on the classification, while new concepts are integrated where they are explicitly required.

Stability also supports the work of national institutes and registers. A national version derived from NACE, usually with a fifth digit, must fit the European framework, and a stable European framework means that national versions need only be updated where the European structure changed. The Irish example shows the national step: during 2025 (FIXED), Eurostat finalised guidance and the Irish Business Register completed updating the coding of enterprises to NACE Rev. 2.1. That work is smaller where the structure is maintained, and larger where it is restructured. Stability in the European text therefore reduces the recoding burden, without removing the need to recode where change occurred.

What does stability not mean?

Stability does not mean that a code keeps its meaning across versions without checking, and it does not mean that an entry in a register stays the same. A class with a one to one correspondence has the same scope in both versions, as stated in the correspondence passage, but that statement must be verified for the class concerned in the table, and the notes must be read to confirm it. A class that stayed the same in structure may still have a changed note, if a boundary example was added or clarified. An entry in a register is confirmed by the institute or register that holds it, on its own timetable, and a stable classification does not remove the need for that confirmation. Stability is a property of the adopted structure. Confirmation is a separate step for an entry.

Check the overview page for the stability aim, check the correspondence table for the class to see if it is one to one, and confirm any entry with the national statistical institute or the business register that holds the record.