How do you use the ISIC index?

The ISIC index in ISIC Rev. 5, UN Statistics Division, is an alphabetical finding aid that points from activity descriptions to the categories that may cover them. It is a starting point for research, not a final answer, because an index entry can point to several categories and the explanatory notes must then decide between them. Used that way, the index saves time without replacing the judgement that the definitions require.

How should you phrase what you look up?

Describe the activity in plain words before opening the index, and try more than one phrasing if the first search comes up empty. Index entries follow the wording of the classification, not the wording of a shopfront, a website, or everyday speech, so a term that feels natural to a reader may not be the term the index uses. Searching under a synonym, under a broader term, and under a narrower term often turns up entries that a single search misses. Write down the activity first, in a sentence, and keep that sentence in view while you search: it stops the search from drifting toward entries that sound attractive but describe a different activity. The index rewards a clear description; a vague word points everywhere and therefore nowhere in particular.

What do you do when one entry points to several categories?

Treat the list of pointers as a shortlist, not as a set of equal answers. Open each candidate category in the UNSD structure for ISIC Rev. 5, UN Statistics Division, read its explanatory note, and test the activity you wrote down against the definition, the includes list, and the excludes list. Often one note will claim the activity and another will exclude it, and the shortlist collapses to a single candidate. Where two candidates still fit, read the notes at the level above them as well, since a section or division note sometimes states a principle that separates them. Do not pick the first entry out of convenience, or the entry whose title matches your search term most closely: the index is alphabetical, not ranked by relevance. The decision belongs to the notes, and the index has done its job once it has given you the candidates to test.

Where does the index stop being useful?

The index is a way into the structure, not a substitute for the structure. It cannot resolve a borderline case, it cannot tell you the level at which to report, and it cannot supply the version label, the reference period, or the source note that a published table needs. A reader who copies a code straight from an index entry into a table has skipped the very step that makes the code defensible: reading the note and confirming that the code exists in Rev. 5 with the scope the reader assumes. A table built from such a shortcut also fails the simplest audit, since a later reader who opens the structure cannot see why that code was chosen over the other candidates the index listed. The index also ages in a particular way: entries added for new activities sit alongside older entries, and a reader working from memory of an earlier revision may follow an entry that the Rev. 5 structure has since redirected. Always confirm the entry against the current UNSD Rev. 5 detail before using it, and treat any mismatch between the index and the structure as a reason to follow the structure.

From index entry to checked category, in order

Step	Action	Why it matters
1	Write the activity in plain words	The search stays anchored to the activity, not to a label
2	Look the activity up under several phrasings	One wording may miss the entry the classification uses
3	Collect every category the entries point to	A single entry can hide a shortlist of candidates
4	Read each candidate note, including excludes lists	The notes decide between candidates the index cannot rank
5	Record the chosen category with its version label	The result can be checked later against the UNSD structure

Follow the steps in order and resist the temptation to stop at step 2. The time saved by the index is real, but it is saved at the finding stage, not at the checking stage, and a shortcut that skips the notes gives back every minute it saved when the error surfaces later.

Used with that restraint, the index is one of the most practical tools in the classification: a quick way in, followed by a careful reading of the definitions that actually decide the matter.

This guide explains a finding aid for statistical classification, and it offers no ruling on any reader’s own case. It does not fix a code, a principal activity, or a registration for anyone, and the code that applies to a specific record is to be confirmed with the national statistical institute or business register that holds the record.