流行病学研究中的样本代表性问题(一)

研究的样本代表性一直是流行病学领域内具有争议性的话题之一。本文首先对流行病学样本代表性进行定义，同时对研究人群、源人群、目标人群、内部真实性、外部真实性等相关流行病学基本概念进行阐述。在此基础上，本文深入分析了横断面研究、队列研究、病例对照研究、干预性研究四种主要流行病学研究设计中样本代表性的价值和实际可行性。总而言之，除针对人群疾病或健康现状的横断面研究外，多数涉及病因或干预效果推断的流行病学研究不应过度强调样本代表性。

Representativeness issues in epidemiological studies

Representativeness has long been a contentious topic in epidemiology. The review starts with defining representativeness in epidemiology and describing fundamental epidemiological concepts including study population, source population, target population, internal validity, and external validity. In addition, it elaborates the role and practicality of representativeness in four major epidemiological study designs including cross-sectional, cohort, case-control, and intervention studies. In summary, representativeness is an important consideration in cross-sectional studies of investigating disease or health status in the target population, but cannot be overstated in epidemiological studies for causal inferences regarding exposure-outcome relationships or intervention effects.