Difference-in-Differences Estimators of Intertemporal Treatment Effects

Working Paper: NBER ID: w29873

Authors: Clément de Chaisemartin; Xavier Dhaultfoeuille

Abstract: We study treatment-effect estimation using panel data. The treatment may be nonbinary, non-absorbing, and the outcome may be affected by the treatment lags. We make parallel-trends assumptions, but do not restrict treatment effect heterogeneity, unlike commonly-used two-way-fixed-effects regressions. We propose reduced-form event-study estimators of the effect of being exposed to a weakly higher treatment dose for ℓ periods. We also propose normalized event-study estimators, that estimate a weighted average of the effects of the current treatment and its lags. Finally, we show that the reduced-form estimators can be combined into an economically interpretable cost-benefit ratio.

Keywords: treatment effects; panel data; event-study estimators

JEL Codes: C21; C23


Causal Claims Network Graph

Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.


Causal Claims

CauseEffect
exposure to a weakly higher treatment dose (C90)treatment effects (C22)
treatment effects (C22)lagged treatment effects (C22)
treatment effects (C22)outcomes (P47)
treatment assignments (C90)potential outcomes (D79)
treatment changes (C22)cost-benefit ratio (H43)
banking deregulations (G28)persistent effects (C41)

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