Department of Epidemiology, University of Washington School of Public Health, Seattle, USA.
Neurology. 2012 Jun 5;78(23):1886-91. doi: 10.1212/WNL.0b013e318258f812.
Clinical and epidemiologic investigations are paying increasing attention to the critical constructs of "representativeness" of study samples and "generalizability" of study results. This is a laudable trend and yet, these key concepts are often misconstrued and conflated, masking the central issues of internal and external validity. The authors define these issues and demonstrate how they are related to one another and to generalizability. Providing examples, they identify threats to validity from different forms of bias and confounding. They also lay out relevant practical issues in study design, from sample selection to assessment of exposures, in both clinic-based and population-based settings.
临床和流行病学研究越来越关注研究样本的“代表性”和研究结果的“可推广性”这两个关键概念。这是一个值得称赞的趋势，但这些关键概念经常被误解和混淆，掩盖了内部和外部有效性的核心问题。作者定义了这些问题，并展示了它们如何相互关联以及与可推广性的关系。通过举例，他们确定了不同形式的偏倚和混杂对有效性的威胁。他们还从基于临床和基于人群的研究设置中的样本选择到暴露评估等方面，阐述了研究设计中的相关实际问题。
