CAUSALab and Departments of Epidemiology and Biostatistics, Harvard T H Chan School of Public Health, Boston, MA, USA.
Department of Communicable Diseases, National Centre of Epidemiology, Institute of Health Carlos III, 28029 Madrid, Spain
BMJ. 2023 Jun 7;381:1135. doi: 10.1136/bmj.p1135.
Effect estimates may be biased when the study design or the data analysis is conditional on a collider—a variable that is caused by two other variables. Causal directed acyclic graphs are a helpful tool to identify colliders that may introduce selection bias in observational research.
当研究设计或数据分析取决于一种由两个其他变量引起的“碰撞器”(collider)变量时,效果估计可能会产生偏差。有向无环图(Causal Directed Acyclic Graphs)是一种有用的工具,可以识别可能在观察性研究中引入选择偏差的碰撞器。