Walter S D
Rev Epidemiol Sante Publique. 1984;32(3-4):206-11.
Misclassification of clinical data occurs commonly, because of measurement or judgmental errors, or because of bias in the observational method. The sensitivity and specificity of a given observer (or method) may sometimes be estimated by comparison with an independent "definitive" diagnosis; this is not routinely practical, however, if the "definitive" method involves additional risk or cost. A second possibility is to compare two independent, fallible observers, using an index of agreement such as the kappa statistic; the misclassification probabilities are not then estimable, and the agreement indices have the disadvantage of being dependent on the population prevalence. In contrast, if three or more independent observers are used, their reliability may be assessed by the direct estimation of sensitivity and specificity. An example is given of a series of patients who were independently evaluated by three radiologists.
临床数据的错误分类很常见，这是由于测量或判断错误，或者是由于观察方法存在偏差。有时可以通过与独立的“确定性”诊断进行比较来估计给定观察者（或方法）的敏感性和特异性；然而，如果“确定性”方法涉及额外的风险或成本，这在常规情况下是不实际的。第二种可能性是使用一致性指数（如kappa统计量）比较两个独立的、可能出错的观察者；此时错误分类概率无法估计，并且一致性指数具有依赖于人群患病率的缺点。相比之下，如果使用三个或更多独立观察者，则可以通过直接估计敏感性和特异性来评估他们的可靠性。给出了一个由三位放射科医生对一系列患者进行独立评估的例子。
