Difference-in-Differences Estimators of Intertemporal Treatment Effects

• 成果类型: Article
• 署名作者: de Chaisemartin, Clement; D'Haultfoeuille, Xavier
• 署名单位: Institut Polytechnique de Paris; ENSAE Paris; Institut Polytechnique de Paris
• 刊物名称: REVIEW OF ECONOMICS AND STATISTICS
• ISSN/ISSBN: 0034-6535
• DOI: 10.1162/rest_a_01414
• 发表日期: 2026
• 关键词: inference

摘要

We study treatment-effect estimation using panel data. The treatment may be nonbinary, nonabsorbing, and the outcome may be affected by treatment lags. We make a parallel-trends assumption and propose event-study estimators of the effect of being exposed to a weakly higher treatment dose for & ell; periods. We also propose normalized estimators that estimate a weighted average of the effects of the current treatment and its lags. We also analyze commonly used two-way fixed-effects regressions. Unlike our estimators, they can be biased in the presence of heterogeneous treatment effects. A local-projection version of those regressions is biased even with homogeneous effects.