Two-way Fixed Effects and Differences-in-Differences in Heterogeneous Adoption Designs without Stayers

Clément de Chaisemartin, Diego Ciccia (), Xavier D'Haultfoeuille and Felix Knau

Working Papers from HAL

Abstract: We consider treatment-effect estimation under a parallel trends assumption, in designs where no unit is treated at period one, all units receive a strictly positive dose at period two, and the dose varies across units. There are therefore no true control groups in such cases. First, we develop a test of the assumption that the treatment effect is mean independent of the treatment, under which the commonly used two-way fixed-effects estimator is consistent. When this test is rejected or lacks power, we propose alternative estimators, robust to heterogeneous effects. If there are units with a period-two treatment arbitrarily close to zero, the robust estimator is a difference-in-difference using units with a period-two treatment below a bandwidth as controls. Without such units, we propose non-parametric bounds, and an estimator relying on a parametric specification of treatment-effect heterogeneity. We use our results to revisit Pierce and Schott (2016) and Enikolopov et al. (2011).

Date: 2025-01-10
New Economics Papers: this item is included in nep-ecm
Note: View the original document on HAL open archive server: https://sciencespo.hal.science/hal-03873937v2
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
https://sciencespo.hal.science/hal-03873937v2/document (application/pdf)

Related works:
Working Paper: Two-way Fixed Effects and Differences-in-Differences in Heterogeneous Adoption Designs without Stayers (2025)
Working Paper: Two-way Fixed Effects and Differences-in-Differences in Heterogeneous Adoption Designs without Stayers (2024)
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:hal:wpaper:hal-03873937

Access Statistics for this paper

More papers in Working Papers from HAL
Bibliographic data for series maintained by CCSD ().