The following two derived variables measure occupational status: Treimans Standard International Occupational Scale (SIOPS) and Ganzeboom et al's International socio-Economic Index of Occupational Status. We are grateful to Harry Ganzeboom of Utrecht University for supplying us with the algorithms to create these variables from ISCO88 (International Standard Classification of Occupations) codes.
SIOPS - Standard International Occupational Scale
Treiman originally constructed this scale in 1977 by averaging results of prestige evaluations carried out in approximately sixty countries. Occupational titles from national and local prestige studies were matched to the three-digit version of ISCO-68. Ganzeboom and Treiman (1995) have now updated the scale for ISCO-88 codes.
ISEI - International Socio-Economic Index of Occupational Status
International SocioEconomic Index of Occupational Status (ISEI) measures the attributes of occupation that convert a person's education into income. In constructing the scale, occupation was scaled so that it captures as much as possible of the indirect influence of education on income. Optimal scaling techniques were used and were carried out by an iterative algorithm involving a series of regression equations.
The data used for constructing the scale were taken from an International Stratification and Mobility File which consists of extracts of data from a wide variety of countries, ranging from underdeveloped countries (such as India) to the most developed countries (such as the United states).The variables used in the analysis included respondent's education, occupation, age and income. Of course there are problems of comparability of educational classifications across countries. After experimenting with a variety of scaling procedures it was found that a logarithmic transformation of the number of years of schooling was a reasonable approximation to the level of education and so this was used as the common metric for the education variable. To obtain a measure of income comparable between societies, a logarithmic transformation of income was converted to Z scores within each country.
When constructing the ISEI scale the data used was for adult males, employed full time. Since women were omitted from the data, ISEI scores for characteristically female occupations have been estimated from the education and incomes of the relatively rare men in these jobs.
It was not possible to derive these variables for the 2% Individual SAR because, for confidentiality reasons, the individual SAR does not have as much detailed occupational information as does the 1% household SAR.
The SAR SIOPS and ISEI variables were created as simple recodes of ISCO88 three digit occupation codes. Persons with ISCO88COM codes of 247 have been given the same SIOPS and ISEI values as persons with ISCO code 344 (Customs, tax and related government associate professionals).
The only other difference we noticed between the ISCO88COM and ISCO88 coding schemes is that Armed forces occupations have the code 010 in ISCO88COM but are given the code 011 in ISCO88. We have given Armed Forces occupations missing values for the SARs variables SIOPS and ISEI.
References
OOSS User Guide, Occupational Information Unit, Census Division,
OPCS, Titchfield
Ganzeboom, H B G; De Graaf, P M; Treiman, D J (1992): A Standard
International SocioEconomic Index of Occupational Status. Social Science Research 21,156
Ganzeboom, H B G; Treiman, D J (1995): Internationally Comparable
Measures of Occupational Status for the 1988 International Standard Classification of Occupations, forthcoming in Social Science.
Research.International Labour Office (1990): International Standard Classification of Occupations 1988. International Labour Office Publications, Geneva.
OPCS Occupation Support Service (1994): OOSS USER GUIDE:1
Mapping of Standard Occupational Classification (SOC) to International Standard Classification of Occupations European Community Version (ISCO88 COM). OPCS Occupation Support Service.
Prandy, K. (1990); Revised Cambridge scale of occupation. Sociology Vol.24. No.4.
Scale scores for SIOPS and ISEI
SIOPS ISEI
51 55 Legislators, Senior officials and managers
67 70 Legislators and senior officials
64 77 Legislators
71 77 Senior government officials
63 66 Senior Local Government Officials
63 55 Senior officials of s pecial-interest organisations
60 68 Corporate Managers
70 70 Directors and chief executives
63 67 Department managers
60 61 Other department managers
55 58 Office managers
65 64 Military officers
50 51 General managers
62 70 Professionals
63 69 Physical, mathematical and engineering