The design versus the analysis of observational studies for causal effects:: Parallels with the design of randomized trials
The design versus the analysis of observational studies for causal effects:: Parallels with the design of randomized trials
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DOI：
10.1002/sim.2739
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发表时间：
2007-01-15
影响因子：
2
通讯作者：
Rubin, Donald B.
中科院分区：
文献类型：
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作者：
Rubin, Donald B.
为了估计治疗的因果效应，随机实验通常被认为是金标准。然而，由于各种原因，如道德问题、过度的费用或及时性，它们往往不可行。因此，我们对因果效应的大部分认识必须来自非随机观察性研究。本文将倡导这样一种观点，即观察性研究可以而且应该尽可能接近随机实验。特别是，观察性研究的设计应仅使用背景信息，以创建相似治疗和对照单位的亚组，其中“相似”是指其背景变量的分布。非常重要的是，这项活动应该在不接触任何结果数据的情况下进行，从而确保设计的客观性。在许多情况下，可以使用倾向评分方法来实现类似治疗和对照单位亚组的客观创建，这些亚组在协变量方面是平衡的。这一立场背后的理论观点，将提出一个特定的应用程序在美国烟草诉讼的背景下。本申请使用倾向评分方法创建治疗单位（男性当前吸烟者）和对照单位（男性从不吸烟者）的亚组，这些亚组在观察到的背景特征分布方面至少与随机分组时相似。然后，这些亚组的集合就观察到的协变量而言“近似”于随机区组实验。版权所有（c）2006约翰威利父子有限公司。
For estimating causal effects of treatments, randomized experiments are generally considered the gold standard. Nevertheless, they are often infeasible to conduct for a variety of reasons, such as ethical concerns, excessive expense, or timeliness. Consequently, much of our knowledge of causal effects must come from non-randomized observational studies. This article will advocate the position that observational studies can and should be designed to approximate randomized experiments as closely as possible. In particular, observational studies should be designed using only background information to create subgroups of similar treated and control units, where 'similar' here refers to their distributions of background variables. Of great importance, this activity should be conducted without any access to any outcome data, thereby assuring the objectivity of the design. In many situations, this objective creation of subgroups of similar treated and control units, which are balanced with respect to covariates, can be accomplished using propensity score methods. The theoretical perspective underlying this position will be presented followed by a particular application in the context of the US tobacco litigation. This application uses propensity score methods to create subgroups of treated units (male current smokers) and control units (male never smokers) who are at least as similar with respect to their distributions of observed background characteristics as if they had been randomized. The collection of these subgroups then 'approximate' a randomized block experiment with respect to the observed covariates. Copyright (c) 2006 John Wiley & Sons, Ltd.