nonresponse bias, (in epidemiology) errors that may develop when a part of those selected and identified as study subjects cannot or will not participate in the study. The bias may occur when the group of nonrespondents differs systematically from respondents with respect to exposure or disease status. To minimize this bias, a high participation rate is necessary, or a survey is made of nonresponders to determine whether or how they might differ with regard to the risk of disease or exposure.
