PDF(Pubmed)
Abstract：
As in any observational study, in a case-control study a primary concern is potential unmeasured confounders. Bias, due to unmeasured confounders, can result in a false discovery of an apparent treatment effect when there is none. Replication of an observational study, which tries to provide multiple analyses of the data where the biases affecting each analysis are thought to be different, is one way to strengthen the evidence from an observational study. Evidence factors allow for internal replication by testing a hypothesis using multiple comparisons in a way that the comparisons yield independent evidence and differ in the sources of potential bias. We construct evidence factors in a case-control study in which there are two types of cases, \"narrow\" cases which are thought to be potentially more affected by the exposure and \"marginal\" cases which are thought to have more heterogeneous causes. We develop and study an inference procedure for using such evidence factors and apply it to a study of the effect of sigmoidoscopy screening on colorectal cancer.
摘要：
和任何观察性研究一样，在一项病例对照研究中,主要关注的问题是潜在的无法测量的混杂因素.偏见,由于无法测量的混杂因素，当没有明显的治疗效果时，可能会导致错误的发现。复制一项观察性研究，它试图提供对数据的多种分析，其中影响每种分析的偏见被认为是不同的，是加强观察性研究证据的一种方法。证据因素允许内部复制，方法是使用多次比较来检验假设，从而使比较产生独立的证据并且在潜在偏差的来源上有所不同。我们在病例对照研究中构建了证据因素，其中有两种类型的病例，被认为受暴露影响更大的“狭窄”病例和被认为具有更多不同原因的“边缘”病例。我们开发并研究了使用此类证据因素的推断程序，并将其应用于乙状结肠镜筛查对结直肠癌影响的研究。
