一、混杂因素的概念在队列方法与病例—对照调查的比较研究中,使用七测验、X~2等寻找疾病与因素的联系,以相对危险度(RR)来测量特征及疾病的联系强度。对于病例—对照来说,除了要考查的危险因素外,还有许多的背景因素可能不同,其中有些背景因素会混杂或掩盖危险因素的真实效应,如果在一项比较研究的设计或分析阶段忽视了混杂的控制,将影响结果的真实性,因为他们的结果的混杂效应可能被误认是危险因素所改,严重时会导致似是而非的结论,给思维布上陷井,把人引入岐途。例如,暴露与病疾之间的相关关系中,年 First, the concept of confounding factors in the cohort method and case-control survey of comparative studies, the use of seven tests, X ~ 2 and other factors to find the relationship between disease and relative risk (RR) to measure the characteristics and disease strength of contact. For case-control, there are a number of background factors that may vary, in addition to the risk factors to be examined, some of which may be mixed or masked to the true effect of risk factors. If ignored in a comparative design or analysis phase The mixed controls will affect the authenticity of the results because the mixed effects of their results may be mistaken for the risk factors and, in severe cases, lead to plausible conclusions that put the mind in the trap and lead people astray. For example, the correlation between exposure and illness is in years