论文标题
关于控制变量在回归分析中的滋扰
On the Nuisance of Control Variables in Regression Analysis
论文作者
论文摘要
控制变量包括在回归分析中，以估计治疗对结果的因果作用。在本文中，我们认为，控制量的估计效应大小不可能本身具有因果解释。这是因为即使有效的对照也可能是内源性的，并且代表了在结果上共同运作的几种不同因果机制的组合，这在理论上很难解释。因此，我们建议避免解释控制的边际效应，而要关注感兴趣的主要变量，为此，可以建立合理的识别参数。为了防止错误的管理或政策含义，应明确标记控制变量的系数没有因果解释或完全从回归表中省略。此外，我们建议不要将控制变量估计值用于随后的理论构建和荟萃分析。
Control variables are included in regression analyses to estimate the causal effect of a treatment on an outcome. In this paper, we argue that the estimated effect sizes of controls are unlikely to have a causal interpretation themselves, though. This is because even valid controls are possibly endogenous and represent a combination of several different causal mechanisms operating jointly on the outcome, which is hard to interpret theoretically. Therefore, we recommend refraining from interpreting marginal effects of controls and focusing on the main variables of interest, for which a plausible identification argument can be established. To prevent erroneous managerial or policy implications, coefficients of control variables should be clearly marked as not having a causal interpretation or omitted from regression tables altogether. Moreover, we advise against using control variable estimates for subsequent theory building and meta-analyses.
