Where are official Rev. 5 documents published?

Official Rev. 5 documents for ISIC Rev. 5, UN Statistics Division, are published through the UN Statistics Division classification pages, including the classification detail page and the Rev. 5 publication PDF. Those pages are the first place to look for the structure, the explanatory notes and the correspondence material. A reader who needs an authoritative answer should start there, and treat any other site, including secondary indexes, as a finding aid only.

Where should a search for Rev. 5 begin?

The opening paragraph answers this directly: through the UN Statistics Division classification pages, including the classification detail page and the Rev. 5 publication PDF. Beginning there, rather than with a general web search, changes the quality of everything that follows. A general search returns a mixture of official pages, secondary summaries, training slides, and outdated mirrors, ranked by visibility rather than authority. A search that starts at UNSD returns the authoritative text first, and the reader can then judge every other result against it.

Starting at UNSD also saves time in the long run. A reader who begins with a secondary summary often ends up verifying it against UNSD anyway, once a doubt arises, which means the secondary step added a detour rather than a shortcut. A reader who begins at UNSD has the verification already in hand, and can use secondary material afterwards as a finding aid, knowing exactly where it stands relative to the official text.

What does each official source contain?

The two sources named in the opening paragraph complement each other, and knowing what each holds helps a reader choose the right one for the task at hand. The classification detail page presents the structure itself: sections, divisions, groups and classes, with explanatory notes, includes and excludes lists, and the correspondence material that links Rev. 5 to Rev. 4. It is the source for checking a specific category, tracing a mapping, or confirming the scope behind a figure.

The Rev. 5 publication PDF gathers the revision as a document: the structure plus the introductory, methodological, and explanatory material that frames it. It is the source for describing the revision as a whole, for understanding its principles, and for citing the standard in a bibliography. A reader who needs one category should open the detail page. A reader who needs the revision’s reasoning should open the publication. A reader who needs both should open both, and cite each for what it actually provided.

How should secondary indexes be used?

Secondary indexes, vendor pages, and training sites have a legitimate role, and this guide does not suggest ignoring them. They can help a reader discover that a category exists, understand a concept in plainer language, or find a national implementation that derives from Rev. 5. Their role, however, is that of a finding aid, as the opening paragraph puts it. A finding aid points toward the authoritative text. It does not replace it, and it should not be cited as if it did.

A practical way to keep the roles straight is to maintain two kinds of notes: discovery notes, which may cite any helpful source, and publication notes, which cite UNSD for every code statement. Discovery notes can be informal and wide-ranging. Publication notes must be narrow and official. When a discovery note and the UNSD text disagree, the publication note follows UNSD, and the discovery note should be corrected or annotated so the disagreement does not resurface later.

What if an official page is hard to navigate?

UNSD classification pages are reference tools, not reading material, and first-time visitors sometimes find them dense. The density is a feature of their job: they must present hundreds of categories with full notes, without simplifying away distinctions that matter for coding. A reader who finds them forbidding should narrow the task rather than abandon the source. Search within the detail page for the category in question, read that category’s note in full, and follow its cross-references, instead of trying to absorb the whole structure at once.

Another useful tactic is to arrive at UNSD with a specific question, such as the scope of one category or the mapping of one row, rather than with a general wish to understand Rev. 5. Specific questions have specific answers on the detail page, and a series of specific answers builds understanding faster than a general browse. If a question remains unclear after reading the official note, the honest next step is to record the uncertainty and consult the national documentation or the publication’s explanatory material, not to settle the question from a secondary summary that happens to sound confident.

This guide describes where official documents are published and offers no ruling on any reader’s individual classification. For a code, principal activity, or registration question about a particular record, the national statistical institute or business register holding that record is the body to confirm with.