What alignment between ISIC Rev 5 and regional classifications is claimed?

The only alignment claim verified for ISIC Rev. 5 in the pages consulted is the general claim made by the United Nations Statistics Division itself: that the fifth revision facilitates international comparison through increased alignment with existing regional classifications. That claim is quoted here in the Division’s own terms, and no specific alignment detail is asserted in this guide. No statement is made here that a named ISIC Rev. 5 category aligns with a named NACE Rev.

2.1 category, that the alignment is one to one, or that the two revisions were adopted on the same timetable. Those would be specific claims, and they were not verified in the Division and Eurostat pages consulted for this guide. A reader who needs a specific alignment should consult the correspondence between the two classifications, and should record the mapping type shown there.

Why is the general claim not enough for a specific comparison?

A general claim about alignment describes an aim and a direction. It does not describe the relationship between two specific categories. The relationship between specific categories is shown in a correspondence table, which Eurostat describes as a table between two different classifications that shows the relationship between all positions of the two classifications involved. A correspondence table can show a one to one relationship, a one to many relationship, a many to one relationship, or a split, and each type has a different meaning for a comparison. A general alignment claim, however strong, does not tell a reader which type applies to a given pair of categories. A reader who treats a general claim as a specific correspondence will assume a one to one result where the table may show a split, and will misread the comparison. The general claim is therefore a starting point for a check, not a substitute for it.

What is a regional classification, in this context?

A regional classification is a classification adopted for a region, derived from the international standard, with additional detail for regional use. NACE is the European example: it is derived from ISIC, it is more detailed than ISIC at lower levels, and it has exactly the same items at the highest levels, as Eurostat states. Other regions have their own classifications, derived from ISIC in the same way, and the Division’s claim about increased alignment refers to those regional classifications in general, not to NACE alone. The claim therefore covers a family of classifications, and it does not single out any one of them for a specific alignment statement. A reader should not read the general claim as a statement about NACE Rev. 2.1 alone, and should not read it as a statement that every regional classification aligns with ISIC Rev. 5 in the same way. Each regional classification has its own structure, its own adoption timetable, and its own correspondence table with ISIC.

What was verified, and what was not verified?

Three points were verified. First, the Division states that ISIC Rev. 5 facilitates international comparison through increased alignment with existing regional classifications. Second, the Division states that the structure of Rev. 5 was endorsed in March 2023 (FIXED) and the introduction and explanatory notes in March 2024 (FIXED). Third, Eurostat states that NACE is derived from ISIC and is more detailed at lower levels, with the same items at the highest levels. Three points were not verified, and are not asserted here. First, no specific category by category alignment between ISIC Rev. 5 and NACE Rev. 2.1 was verified. Second, no statement that NACE Rev. 2.1 was designed to match ISIC Rev. 5 category for category was verified. Third, no joint timetable for the two revisions was verified. The table below keeps the verified and the unverified points apart, so that a reader can see the boundary of the claim.

Point	Status in this guide
Increased alignment in general, as stated by the Division	Verified, quoted in the Division’s terms
Structure endorsed March 2023 (FIXED), notes March 2024 (FIXED)	Verified
NACE derived from ISIC, more detailed below, same at the top	Verified, as stated by Eurostat
Specific category alignment, ISIC Rev. 5 to NACE Rev. 2.1	Not verified, not asserted
Joint timetable for the two revisions	Not verified, not asserted

The table is a verification record. It is more useful than a general statement, because it tells the reader exactly what can be relied on and what still needs a correspondence check.

How is a specific alignment checked?

A specific alignment is checked in the correspondence table between ISIC and NACE for the revisions in use, and in the explanatory notes for the two categories. The reader opens the ISIC category, opens the NACE category, reads the note for each, and records the mapping type shown in the table. Where the table shows a one to many mapping, the reader records that the ISIC category is split in NACE, and that the split does not by itself pick a NACE class for a specific unit. Where the table shows a many to one mapping, the reader records that two NACE categories fall in one ISIC category, and that the aggregate is the comparable level. Where the table shows a one to one mapping, the reader records that, with the revisions named, because a one to one mapping in one pair of revisions may not hold in the next pair. The check is category by category, and it is never completed by a general claim.

What does alignment not decide?

Alignment between classifications does not decide the code for any unit, and it does not decide tax, licensing, funding, collective agreement or social security questions. Alignment is a property of two statistical classifications, and it describes how their categories relate for the purpose of comparison. A specific business entry is checked with the national statistical institute or the business register that holds the record. The meaning of a category in either classification is confirmed in the publication for that classification and revision.

Quote the general claim only in the Division’s terms, check each specific alignment in the correspondence table, and confirm a business entry with the institute or register that holds it. ”