Agreement between self- and partner reports obtained by a self-administered questionnaire: medical and lifestyle information.

We examined agreement between the subjects' self- and partner-reports of such epidemiological information as medical and family history, smoking and drinking habit and physical activity. Information was obtained by a self-administered questionnaire which was completed by 224 workers (subjects) and by their partners in 1997. Agreement was assessed by calculating kappa statistic, intraclass correlation coefficient (ICC), and per cent agreement. Per cent agreement ranged from a low of 76.2 for general life stress to a high of 98.0 for angina/myocardial infarction and diabetes mellitus as present illness. Kappa values ranged from a low of 0.34 for general life stress to a high of 0.86 for smoking habit. Compared to subjects, their partners tended to report lower level of both exposures (continuous variables) and presence (dichotomous variables). The average kappa was 0.64 for wife-surrogates, whereas 0.53 for husband-surrogates. Overall, our finding suggested that partners could provide acceptable information for the concrete and directly-observable variables (e.g. such present illness as hypertension which required daily medication, or smoking/drinking habit itself), but not so for detailed/subjective variables (e.g. number of cigarettes smoked per day or general life stress).