How is ISIC used in national classifications?

ISIC is used in national classifications in two ways: directly, as the national classification, or as the basis from which a national classification is derived. The United Nations Statistics Division states that, since the adoption of the original version of ISIC in 1948 (FIXED), the majority of countries around the world have used ISIC as their national activity classification, or have developed national classifications derived from ISIC.

ISIC has therefore provided guidance to countries in developing national activity classifications, and has become an important tool for comparing statistical data on economic activities at the international level. The national version is the classification a reader will usually meet in a register or a national statistic. ISIC is the common reference behind it.

What does derived from ISIC mean?

Derived from ISIC means that the national classification takes the ISIC structure and principles as its starting point, keeps the same items at the highest levels, and adds detail at lower levels for national use. Eurostat states the pattern for NACE, which is the European derivation: NACE is derived from ISIC, it is more detailed than ISIC, and ISIC and NACE have exactly the same items at the highest levels, while NACE is typically more detailed at lower levels. Statistics Netherlands states the same pattern for the Dutch SBI: the first two levels of SBI are aligned with ISIC, and, with a few exceptions, the first four digits of SBI are identical to NACE, while the fifth level is specific to the Netherlands. The pattern is therefore a hierarchy of derivations: ISIC at the international level, NACE at the European level, and a national version, such as the SBI, at the national level, each adding detail below the levels it shares with the level above. A reader who understands that hierarchy can place any national code in its international context, by aggregating it to the level it shares with ISIC.

How does a national version add detail?

A national version adds detail by subdividing a category from the level above, by adding a level below the class, or by adding categories for activities of particular national importance. The Dutch SBI adds a fifth level, with a maximum of five digits, as Statistics Netherlands states. The United Kingdom SIC adds a five digit sub class level for certain classes, as the Office for National Statistics states. The French NAF adds a letter to the four digit class, in the APE code shown in the Sirene record, as Service Public describes. In each case, the added detail is national, and it does not change the category at the level shared with ISIC or NACE. A national code should therefore be read in two parts: the shared part, which is comparable internationally, and the national part, which is comparable only within the national version. A confirmation should state how many digits or characters the code as held contains, and which part is national detail, so that a reader does not compare national detail as if it were international.

How is a national code compared internationally?

A national code is compared internationally by aggregating it to the level it shares with ISIC, or by using the correspondence table between the national classification and ISIC. Aggregation means dropping the national detail and comparing at the division or group level where the categories match. Correspondence means consulting the table that shows the relationship between all positions of the two classifications, and recording the mapping type for the pair. Eurostat describes correspondence tables between two different classifications in those terms, and the same discipline applies to a national to ISIC table. Where the table shows a one to many or split mapping, the comparison should be made at the aggregate, or the split should be described, with the note for each category cited. A direct comparison of national detail with an ISIC category, without aggregation or a correspondence table, compares a national subdivision with an international category, and the result will be misleading.

Level	ISIC	NACE	National version, example
International	ISIC Rev. 5, custodian United Nations Statistics Division	Derived from ISIC	Derived from ISIC, directly or via NACE
European	Common reference	NACE Rev. 2.1, more detailed below	National version derived from NACE in the EU
National	Shared at the highest levels	Shared to four digits, with exceptions	Fifth level or letter suffix, national detail

The table shows the hierarchy of derivations, not a directory of national versions. The national row uses examples verified in the pages consulted, and it does not claim to list every national version. A reader should confirm the derivation for a named country in the institute publication for that country, rather than assuming the table applies unchanged.

What happens when a national classification moves to a new ISIC revision?

When ISIC is revised, national classifications derived from it are reviewed, and they move on their own timetables, set nationally. NACE Rev. 2.1 is the European response to the changes in the world economy since NACE Rev. 2, and national versions such as NAF 2025 in France, SBI 2025 in the Netherlands, and the CSO Business Register recoding in Ireland move on national timetables, verified in the pages consulted for those countries. No single timetable for all national moves was verified, and no date is asserted here for any country not covered by a verified national timetable. A reader who needs the timetable for a named country should open the institute publication for that country, and should record the date with the FIXED or EXPECTED label that the institute text supports. The international revision is the trigger. The national timetable is the date.

What does a national derivation not decide?

A national classification derived from ISIC does not determine the code for any reader, and it does not decide tax, licensing, funding, collective agreement or social security questions. It is a statistical classification, derived from an international statistical standard, for the collection and presentation of statistics. The entry for a specific business is confirmed with the national statistical institute or the business register that holds the record, in the national version the register uses. The meaning of a category is confirmed in the publication for that national version and in the ISIC publication for the revision from which it is derived.

Place the national code in the hierarchy, aggregate to the shared level for an international comparison, and confirm a business entry with the institute or register that holds it. ”