标题： 在具有异质处理效应的事件研究中估计动态处理效应 显示英文标题

标题： Estimating Dynamic Treatment Effects in Event Studies with Heterogeneous Treatment Effects

摘要： 为了估计吸收性处理的动态效应，研究人员通常使用包含处理前后时期的双向固定效应回归。 我们表明，在处理时间在各单元中存在差异的情况下，某个前期或后期的系数可能受到其他时期效应的污染，而明显的前期趋势可能仅由处理效应的异质性引起。 我们提出了一种不受污染的替代估计量，并通过一个实证应用说明了包含前期和后期的双向固定效应回归的相对缺陷。 显示英文摘要

摘要： To estimate the dynamic effects of an absorbing treatment, researchers often use two-way fixed effects regressions that include leads and lags of the treatment. We show that in settings with variation in treatment timing across units, the coefficient on a given lead or lag can be contaminated by effects from other periods, and apparent pretrends can arise solely from treatment effects heterogeneity. We propose an alternative estimator that is free of contamination, and illustrate the relative shortcomings of two-way fixed effects regressions with leads and lags through an empirical application.