Validity of exposure data derived from a structured questionnaire.

It is often convenient to obtain occupational exposure information directly from employees. However, there is little published evidence on the validity of such data. Information from a short, pre-coded, structured questionnaire, administered by non-expert interviewers, was compared with information derived from management in five factories in the printing and plastics industries in England in 1986. Values of sensitivity ranged from 24% to 85% for eight different exposures, and specificity was at least 67% for seven of the eight agents. Those exposures which were described in chemically specific terms tended to have relatively higher specificities but lower sensitivities. Male workers' reports tended to have higher sensitivity but lower specificity compared with those of female workers. Workers who had been employed in the company for more than 10 years were no more accurate than their colleagues. Subjects who reported a phase of subfertility or at least one miscarriage did not have a higher proportion of false positives than the population as a whole, indicating an absence of reporting bias. Major improvements are highly desirable, especially to reduce underreporting of exposures. The use of workers' own names for agents may improve reporting.