流行病学是疾病病因研究的有力工具。由于其研究的对象是人,因而研究结果常受许多因素的干扰而出现偏倚。无答复(nonresponse)问题就是其中一个重要的影响因素。所谓无答复是指未能对所确定观察的对象进行计量或观察。在流行病学研究中,几乎不可避免无答复问题,不论是纵向研究或是横向研究,普查或是抽查。同时无答复的表现形式又是多种多样的,调查对象不合作及拒绝回答问题,失访、漏查、漏检、漏报 Epidemiology is a powerful tool for studying disease etiology. Because the object of its research is human, the results of the study are often biased by many factors. The nonresponse problem is one of the important factors. The so-called non-response means that the observed object is not measured or observed. In epidemiological studies, it is almost inevitable that there is no answer, whether it is a longitudinal study or a horizontal study, a census or a spot check. At the same time, the forms of non-response are various, and the respondents did not cooperate and refused to answer questions, lost to follow-up, missed, missed, or missed reports.