Field entry, published 2026-11-03T00:00:00.000Z, updated 2026-11-03T00:00:00.000Z. Group: The four levels of ISCO-08

What is a major group?

A major group is the broadest tier in ISCO-08, a one digit family that gathers a large set of related occupations before the classification makes any finer distinction. There are 10 major groups in total, and each one stands at the top of its own branch. Everything below a major group, from sub-major groups down to unit groups, sits inside that branch and nowhere else. When a table reports results by major group, it is therefore reporting at the widest level the classification offers, where unlike work is grouped together only because it shares a broad field and a broad skill character.

What kind of similarity holds a major group together?

Major groups are formed around broad similarities in the field of work and in the skill character of the work, rather than around a shared employer, a shared workplace, or a shared job title. That distinction matters, because two people with different titles and different employers can sit in the same major group, while two people with similar sounding titles can sit in different ones. The grouping looks at what the work itself involves at a general level, not at the label printed on a contract or a business card. For example, 2 Professionals gathers professional work as a broad family. The label is deliberately wide, and it would be a mistake to read it as naming one occupation.

How broad is broad in practice?

Breadth at this level is easy to underestimate. A single major group can contain dozens of unit groups once the full hierarchy is unfolded, because each step down divides the family again and again. The 10 major groups together contain 436 unit groups, so the average major group unfolds into more than forty detailed groups, even though the exact number varies from branch to branch. That unfolding is the reason major group figures are useful for big comparisons, such as comparing the overall shape of employment across countries or across years, and also the reason they are useless for describing the detail of any one occupation. A major group total answers a question about scale, not a question about specific work.

What does a major group not tell you?

A major group does not tell you the tasks a person performs, the qualifications a person holds, or the industry in which a person works. It also does not tell you whether two occupations inside it are close neighbours or distant cousins within the same family. Two unit groups can share a major group yet differ sharply in daily tasks, in the knowledge they draw on, and in the settings where the work happens. Readers who treat a major group label as a job description will therefore overread it. The label is a starting point for finding the narrower groups below it, not a summary of any one occupation inside it.

When is the major group level the right level to use?

Use the major group level when the question itself is broad. Questions about the overall mix of professional, clerical, craft, or elementary work, for instance, are naturally answered at this level, because finer detail would swamp the comparison. Use a lower level when the question turns on a particular kind of work, a particular set of tasks, or a boundary between two similar occupations. Moving down is not a sign that the major group was wrong. It is a sign that the question has changed, and that the classification has a finer tool ready for the new question.

How should you read a major group name?

Read the name as a family label, then look immediately for the divisions below it. Ask what sub-major groups split the family, and what distinguishes one split from another. That habit prevents the common error of stopping at the top level and treating the family name as if it were the whole answer. It also builds a useful mental map: ten families at the top, each dividing into a handful of subfamilies, each of those dividing again. With that map in mind, later guides on sub-major, minor, and unit groups become easier to follow, because each one is simply the next step down the same branch you have already started to explore.

Sources checked

1. ILO ISCO-08

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