Questionnaire Reliability and Validity for Aluminum Potroom Workers

As a part of a study on the respiratory symptoms of aluminum potroom workers, the reliability of a self-administered questionnaire and an interview questionnaire was studied with the use of 261 and 49 employees, respectively. The validity of the selfadministered questionnaire (134 persons examined) and the interview questionnaire (90 persons examined) was assessed in a comparison of the statements with the case histories. The reliability of the self-administered questionnaire was fairly high, the kappa coefficient ranging from 0.58 to 0.83, while the reliability of the interview questionnaire varied from—0.03 to 0.45. The same pattern was present with regard to validity, as the self-administered questionnaire showed the highest mean sensitivity, specificity, and agreement in a comparison with the case histories. The self-administered questionnaire seemed to discriminate well between symptomatic and asymptomatic individuals, whereas supplemental information about symptoms, as obtained by a standardized interview questionnaire, appeared to be less valid.