VanderWeele T J
Dept. of Epidemiology, Harvard School of Public Health, 677 Huntington Ave., Boston, MA 02115,
Sociol Methods Res. 2010 May 1;38(4):515-544. doi: 10.1177/0049124110366236.
Definitions of direct and indirect effects are given for settings in which individuals are clustered in groups or neighborhoods and in which treatments are administered at the group level. A particular intervention may affect individual outcomes both through its effect on the individual and by changing the group or neighborhood itself. Identification conditions are given for controlled direct effects and for natural direct and indirect effects. The interpretation of these identification conditions are discussed within the context of neighborhood research and multilevel modeling. Interventions at a single point in time and time-varying interventions are both considered. The definition of direct and indirect effects requires certain stability or no-interference conditions; some discussion is given as to how these no-interference conditions can be relaxed.
针对个体聚集在群组或社区中且治疗在群组层面进行的情况，给出了直接效应和间接效应的定义。一项特定干预可能通过其对个体的影响以及通过改变群组或社区本身来影响个体结果。给出了受控直接效应以及自然直接和间接效应的识别条件。在社区研究和多层次建模的背景下讨论了这些识别条件的解释。同时考虑了单个时间点的干预和随时间变化的干预。直接和间接效应的定义需要某些稳定性或无干扰条件；还讨论了如何放宽这些无干扰条件。
