How do you read an explanatory note?

An explanatory note in ISIC Rev. 5, UN Statistics Division, is the prose definition that accompanies a category, explaining what the category covers and, often, what it does not. Notes are the authoritative guide to a category’s scope, more reliable than the short category title alone, because titles are necessarily brief. A reader who skips the note and works from the title risks placing an activity in a category whose definition excludes it.

What are the parts of a note, and in what order should you read them?

Read the general definition first, because it states the scope in prose before any list narrows it. Then read the includes list, which names activities that belong inside even when a reader might doubt them, and then the excludes list, which names nearby activities that belong elsewhere, usually with a pointer to their proper category. That order matters: the definition gives the principle, the includes list tests it against doubtful cases, and the excludes list draws the border against the most tempting mistakes. A reader who reads only the includes list can still be misled, because an activity can resemble an included one while being named in the excludes list of the same category. Read all three parts every time, even for categories that look familiar, and read the notes of neighbouring categories when a border is in question, since a border is defined from both sides.

Why do titles mislead when notes do not?

Titles are compressed for use in tables, so they drop qualifications that the note keeps. A title may name a familiar word that, in everyday speech, covers a wide range of activities, while the note restricts the category to a defined subset of them, or extends it to activities the title never mentions. The result is a false sense of recognition: the reader thinks the category is understood because the word is familiar, and never opens the note that would correct that impression. This is most dangerous with categories whose titles survived a revision unchanged while their notes changed, because the familiar title invites a reader to carry an old understanding into a new structure. The remedy is mechanical, not clever: never treat a title as a definition, and never quote a category without having read its note at the level you are quoting. Familiarity is a reason to check, not a reason to skip.

How does a note help when an activity sits on a border?

A borderline activity is exactly what notes are written for. Start by writing the activity down in plain words, without using the category title as a description, so you do not smuggle the conclusion into the premise. Then test those words against the definition, the includes list, and the excludes list of each candidate category in turn. Often one note will name the activity, or name something close enough that the pointer it gives resolves the case. When both notes seem to fit, look at the level above: the section and division notes sometimes state a principle, such as how combined activities are treated, that decides between two detailed categories. If the notes still leave the case open, that openness is itself a finding: report at the broader level that is clearly supported, and record the unresolved question, rather than forcing a detailed placement the notes do not support. A note read carefully sometimes says, in effect, that the detail you wanted is not available from the classification alone.

Reading a note aloud, as a working habit

Try this sequence the next time a category matters. First, read the title and set it aside. Second, read the definition slowly and underline, mentally or on paper, the words that limit scope: words that say what kind of activity, done how, for what purpose. Third, read the includes list and ask which of its entries surprised you, since surprise marks the places where your everyday sense of the word diverged from the technical scope. Fourth, read the excludes list and follow each pointer to the category it names, reading that note too, so you see the border from the other side. Fifth, write one sentence in your own words stating what the category covers, and check that sentence against the note before you use the category anywhere. Five steps, a few minutes, and a category that can be defended when someone asks why it was chosen.

That small discipline is the difference between a figure that rests on a definition and a figure that rests on a title. The definition can be checked by anyone who opens the UNSD structure; the title alone cannot.

This guide is about reading statistical definitions, and it decides nothing for any individual reader. It does not assign a code, a principal activity, or a registration, and the code for a given record should be confirmed with the national statistical institute or business register that holds the record.