Colombia: 1964, 1973
France: 1962, 1968, 1975, 1982, 1990
Kenya: 1989
Mexico: 1960, 1970, 1990, 2000
United States: 1960, 1970, 1980, 1990
Vietnam: 1999

Colombia 1964: Persons in the labor force.
Colombia 1973: Persons age 10+, with a job or experienced unemployed.
France 1962-1968: Persons age 14+, in the labor force.
France 1975: Persons age 16+, in the labor force.
France 1982-1990: Persons age 14+, in the labor force.
Kenya 1989: Persons age 10+ who worked for pay or profit, on leave/sick leave, or working on family holdings during the previous seven days.
Mexico 1960: All persons.
Mexico 1970: Persons age 12+ who worked the previous year.
Mexico 1990-2000: Persons age 12+, employed.
United States 1960-1970: Persons age 14+ who had worked within the previous ten years; not armed forces, not new workers (see note).
United States 1980: Persons age 16+ who had worked within the previous five years; not armed forces, not new workers (see note).
United States 1990: Persons age 16+ who had worked within the previous five years; not new workers (see note).
Vietnam 1999: Persons age 13+ who worked at least 6 months in the previous year.
NOTE: "New workers" are persons seeking employment for the first time who had not yet secured their first job.

OCCISCO records the person's primary occupation, coded according to the major categories in the International Standard Classification of Occupations (ISCO) scheme for 1988. For someone with more than one job, the primary occupation is that in which the person had spent the most time or earned the most money.

The basic classifications of occupations for Colombia 1964 and 1973 differ, but not substantially. There is no occupation variable for 1985 and 1993.

Colombia 1973 has many undocumented values. In most cases we coded them into occupational groups on the basis of their first digit(s).

Occupations for all French samples were integrated by the French statistical office into a common classification. Because the French occupation variable is not very detailed, difficulties sometimes arose in making the data correspond with the ISCO system. The elementary workers category for France contains only agricultural workers; persons with non-agricultural occupations that elsewhere might be classified as elementary workers cannot be distinguished.

The question applied to employed persons, whether at work or not, and persons on family holdings.

NOTE: Only a tiny fraction of persons actually reported an occupation.

OCCISCO is coded from the classification used in OCC95US, which integrates differing U.S. classifications into the 1950 U.S. census system. The U.S. samples are fully comparable, aside from the differences in the universe with respect to age, armed forces, and experienced workers not in the labor force.

The Vietnam 1999 census classified occupations using the ISCO 1988 system. The question applied to those persons who worked at least six of the previous twelve months.

NOTE: Although the Vietnam 1999 census used the ISCO classification, virtually all farmers were coded as elementary workers. IPUMS-International codes them there as well, because there was no obvious basis upon which to separate farmers and farm laborers. Judging from their occupational titles, it appears that the criterion of "market-oriented production" was applied to farmers in category 6.

The census of 1989 used a different scheme that is impossible to fit in ISCO. See OCC.