Open AccessCompleteness and Accuracy of Interview Data from Proxy Respondents
Author(s) -
Lorene M. Nelson,
W. T. Longstreth,
Harvey Checkoutay,
Gerald van Belle,
Thomas D. Koepsell
Publication year - 1994
Publication title -
epidemiology
Language(s) - English
Resource type - Journals
eISSN - 1531-5487
pISSN - 1044-3983
DOI - 10.1097/00001648-199403000-00011
Subject(s) - proxy (statistics) , intraclass correlation , statistics , demography , medicine , odds , psychology , mathematics , logistic regression , reproducibility , sociology
To evaluate the quality of exposure data provided by proxy respondents, we used a dual interview protocol in a case-control study of subarachnoid hemorrhage. All control subjects and their proxy respondents were interviewed (N = 283 control-proxy pairs), as were the cases who were able to provide their own information and their proxy respondents (N = 68 case-proxy pairs). The reliability of proxy-derived data was excellent for demographic and body habitus measures (kappa or intraclass correlation range = 0.86-0.99), and all aspects of cigarette smoking history (range = 0.79-0.93). Proxy reliability was somewhat lower for questions regarding medications and hormone preparations (range = 0.55-0.88), alcohol consumption (range = 0.52-0.82), and recreational physical activity (range = 0.55-0.67). Proxy reliability varied according to the relationship of the proxy to the index subject. Relative to the index subjects, proxy respondents tended to underreport the presence or level of exposure. For most exposures, odds ratios computed with proxy-derived data were similar in magnitude to odds ratios obtained with index subject data; important bias due to differential nonresponse or differential misclassification was suggested only for questions regarding hormone replacement therapy. Epidemiologic studies that rely on proxy respondents may require more subjects to offset the effect of nondifferential nonresponse and misclassification on the precision of effect estimates.