Field entry, published 2026-11-03T00:00:00.000Z, updated 2026-11-03T00:00:00.000Z. Group: Skill level and skill specialisation

What are the four skill levels in ISCO-08?

ISCO-08 uses four skill levels, numbered 1 to 4, to describe how complex and wide ranging the tasks and duties of an occupation are. Level 1 covers the simplest and most routine work in the classification, while level 4 covers work whose tasks call for extended analysis, decision making and theoretical knowledge. The levels are a tool for grouping occupations that resemble each other, not a ranking of the people who do the work.

ISCO-08 skill level	What the work typically involves
1	Simple and routine physical or manual tasks, often with hand tools and limited judgement about method
2	Operating machinery or equipment, ordering and storing information, and carrying out tasks that follow established procedures
3	Complex technical and practical tasks that draw on a body of specialised knowledge and require judgement within a defined field
4	Tasks that require extended theoretical understanding, analysis, evaluation and the creation or revision of approaches to problems

How does ISCO-08 define a skill level?

ISCO-08 defines skill as the ability to carry out the tasks and duties of a job. Skill level, in turn, is a function of the complexity and range of those tasks and duties. The International Labour Organization (ILO) measures it operationally by looking at the nature of the work itself, the formal education normally linked to competent performance, and the amount of informal training or previous experience in a related occupation that competent performance requires. No single one of those three considerations settles the matter on its own. A job description that looks demanding on paper may still sit at a lower level if its tasks follow fixed routines, just as a job with modest formal entry requirements may sit higher if its daily decisions are genuinely complex.

That three part view matters because it stops the levels from becoming a simple list of certificates. Education gives one clue about the knowledge a worker is expected to bring, but the classification always returns to the work: what must be done, how many different kinds of task are involved, and how much judgement the worker must exercise while doing them. Training and experience enter the picture for the same reason. A worker may reach competent performance through a long apprenticeship rather than through classroom study, and ISCO-08 is designed to recognise that route without pretending that every route leads to the same level.

Which major groups sit at which level?

The ILO table for ISCO-08 assigns skill levels at major group level, with two exceptions discussed in a companion guide. Managers, in Major Group 1, span levels 3 and 4. Professionals, in Major Group 2, sit at level 4. Technicians and Associate Professionals, in Major Group 3, sit at level 3. Clerical Support Workers, Service and Sales Workers, Skilled Agricultural, Forestry and Fishery Workers, Craft and Related Trades Workers, and Plant and Machine Operators, and Assemblers, in Major Groups 4 to 8, sit at level 2. Elementary Occupations, in Major Group 9, also sit at level 2 in the ILO summary table, a point that surprises readers who expect the lowest group to carry the lowest level. Armed Forces Occupations, in Major Group 0, span levels 1, 2 and 4, and are handled at the second hierarchical level instead.

Reading that table slowly prevents a common error. The major group number does not rise or fall in step with the skill level number. Major Group 9 is the last group in the structure, yet its assigned level is 2, because its characteristic tasks, such as cleaning, basic maintenance and simple manual assistance, are more varied and less purely routine than the simplest tasks at level 1. The numbers for groups and the numbers for levels are two separate systems that happen to share digits, and confusing them produces confident but wrong statements about the classification.

What does a skill level not tell you?

A skill level does not tell you how hard a job feels, how much it pays, how respected it is, or how valuable it is to society. It does not measure physical effort, risk, unsocial hours or the skill a particular worker brings beyond what the occupation normally requires. A level 2 occupation can demand stamina, precision and years of practice, and a level 4 occupation can be badly performed by someone holding the usual qualification. The classification is deliberately narrow: it groups occupations by the complexity and range of their characteristic tasks so that labour statistics can be compared across countries and over time.

It also does not follow a single worker through a career. A person may move between occupations at different levels, or carry out tasks above or below the level of the occupation they are counted in. Statisticians classify the job, using its main tasks and duties, rather than grading the individual. Keeping that distinction in mind is the simplest way to use the four levels well: ask what the occupation normally requires, not what one impressive or struggling worker happens to do on a given day.

Sources checked

1. ILO ISCO-08

Back to the Skill level and skill specialisation group or browse all occupations.