How are two national variants compared?

Two national variants are compared at the shared levels, section to class, and never at the national fifth level, because the shared levels are the same headings in both countries, while the fifth levels are defined separately by each institute. The comparison starts from the European structure, finds the class that describes the activity in general terms, and then checks how each national variant presents that class, including its national detail, its titles, and its register entry. The class is the meeting point. The national detail is the divergence.

A comparison that starts from a national fifth level heading in one country and looks for the same heading in another country will fail, because the heading may not exist there, or may cover different activities. A comparison that starts from the class will succeed, because the class exists in both variants by design.

What is the comparison method?

The comparison method has four steps. First, find the European class in the Eurostat structure and notes, and read its inclusions and exclusions. Second, find the corresponding heading in each national structure, and read the national title and any national note, noting where the national heading subdivides the class. Third, check the correspondence table for each country, to see whether the class continued, merged, split or was renamed in that country’s move to the new version, and whether the country’s timetable for the move differs. Fourth, check the register entry in each country separately, because registers are national, and an entry in one country says nothing about an entry in another. The method keeps the shared and the national apart at every step. The class is shared. The subdivision, the timetable, and the entry are national.

Step	Source	Question answered
European class	Eurostat structure and notes	What does the shared heading cover?
National heading	Institute structure for each country	How does each country present the class?
National movement	Correspondence table for each country	Did the heading move, and when, in each country?
National entry	Register in each country	What entry is held for the unit in that country?

The table above is a method, not a set of codes. The specific headings, timetables and entries must be checked in the institute and register material for the countries concerned.

What must never be compared?

Three comparisons must never be made. First, fifth level headings must never be compared across countries, because they are defined nationally and may not match. Second, codes must never be compared without their versions, because the same digits can mean different things under different versions, and different digits can describe the same activity after renumbering. Third, register entries must never be compared as if one country’s entry decided another country’s entry, because registers are national, and each register holds its own entry under its own rules. A reader who compares a French APE code with a German WZ code digit by digit, without stating versions and without passing through the shared class, will produce a false equivalence. A reader who compares a Dutch fifth level with a Slovenian subclass by title will produce a false match. Both errors look like comparisons. Neither is one.

How do timetables affect a comparison?

Timetables affect a comparison because countries move to the new version on different dates, for registers and for statistics separately. France changes register entries from 1 January 2027 (FIXED). Ireland begins publishing outputs under the new version from January 2026 (FIXED), gradually. The Netherlands implements SBI 2025 gradually from 2026 (EXPECTED), with both versions in use. Slovenia changed its register from 1 January 2025 (FIXED), while its statistical transition runs longer. A comparison of two countries’ figures for the same year can therefore compare different versions, unless the version for each figure is stated. A reader should state the version and the reference period for every figure compared, and should use the correspondence tables and any backcast series to make the comparison on a like for like basis. A comparison that ignores timetables will attribute a classification effect to a real economic change, or a real change to a classification effect.

What does a comparison not decide?

A comparison does not decide the code for any reader, and it does not decide tax, licensing, funding or collective agreement questions in any country. It describes how headings relate across countries, for statistics. The entry for a specific unit in each country is confirmed with the institute or register of that country. This site holds no register and decides no entry. A reader who needs entries in two countries must check both registers separately, with the version stated beside every code, and must not assume that an entry in one country implies an entry in the other.

Compare at the shared class, check national detail, timetables and entries separately in each country, and state the version beside every code in the comparison.