Self-assessed versus expert-assessed occupational exposures.

While self-response to a checklist of substances may be a convenient and inexpensive method for obtaining information on occupational exposure, the validity of such information has not been evaluated. The objective of this report is to provide some evidence concerning validity of self-reported occupational exposures. In the context of a large case-control study, it was possible to compare self-reports with expert assessment, in which a team of industrial hygienists and chemists examined each job history individually and decided on likelihood of exposure. The subjects were 1,910 males who had participated in a population-based case-control study of cancer and occupational exposures conducted in Montreal, Canada, between 1979 and 1985. For each of 11 substances, the two methods of exposure assessment were compared by means of a kappa statistic and by computing the sensitivity and specificity of self-assessment against expert assessment. Kappa values ranged from 0.33 to 0.64. Compared with the expert assessment, specificities of the self-assessment were generally high (0.83-0.97, with a median of 0.90), but sensitivities were low (0.39-0.91, with a median of 0.61). The authors conclude that self-reports of occupational exposure are not sufficiently accurate to warrant their sole use in most community-based studies.