Occupation is used as an indicator of social class and researchers use different criteria for ranking occupations. Many researchers classify occupational in terms of the prestige associated with them, others place more emphasis on the economic rewards attached to them.

As a result, occupational classifications differ and the results of various studies are not strictly comparable. A further problem arises from the fact that it is not possible to identify many members of the bourgeoisie on the basis of their occupations. A person’s occupation does not necessarily say anything about the extent of his investments in private industry.