The quality of retrospective questions about occupational history--a comparison between survey and census data.

The main purpose of the present study was to assess the quality of information about occupational history obtained via retrospective interview questions. This assessment is achieved by linking interview data from the Swedish survey of Living Conditions (ULF) with occupational information about the same individuals obtained from a number of censuses. This has been done for the census years 1960, 1970, 1975 and 1980. In both ULF and the census, occupations have been classified according to the Nordic Occupational Classification (NYK). Both data sources contain errors. There are also differences in definitions and measurement procedures. Still, the survey question on occupational history gives results of good quality in terms of agreement with census data. This is especially the case for coarse levels of the classification scheme (NYK 1-digit level). The agreement is somewhat lower for the comparisons farthest back in time.