"The International Classification of Occupations (ISCO) seeks to facilitate international communication about occupations by providing statisticians with a framework to make internationally comparable occupational data available, and by allowing international occupational data to be produced in a form that can be useful for research as well as for specific decision-making and action-oriented activities." "The current version, known as ISCO-08, was published in 2008 and is the fourth iteration, following ISCO-58, ISCO-68 and ISCO-88." "Since the year 1968, the practice is to revise ISCO every 20 years. ISCO revision can only be undertaken if it is mandated by the ICLS. ISCO-08 revision is currently undertaken by the ILO with the assistance of a Technical Working Group (TWG)."

"In addition to ISCO-08, three versions of ISCO were developed in the past. The first complete version of ISCO was adopted in 1957 by the Ninth International Conference of Labour Statisticians (ICLS), it is known as ISCO-58. ISCO-58 was superseded by ISCO-68, which was adopted by the Eleventh ICLS in 1966. The third version, ISCO-88, was adopted by the Fourteenth ICLS in 1987. Whilst it employs a similar conceptual model to that used for ISCO-88, and the 10 major groups were not changed in concept, ISCO-08 is slightly more detailed at its disaggregate levels and comprises 43 sub-major groups, 131 minor groups and 436 unit groups. Like its predecessor, ISCO-08 provides descriptions for all of the categories identified at each of the four levels of its structure, and can be extended by defining detailed occupations if and when required for specific national or regional purposes."

ISCO is available online free of charge and can be used without prior authorization.

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