Two-Way Fixed Effects and Differences-in-Differences with Heterogeneous Treatment Effects: A Survey
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Linear regressions with period and group fixed effects are widely used to estimate policies' effects: 26 of the 100 most cited papers published by the American Economic Review from 2015 to 2019 estimate such regressions.It has recently been show that those regressions may produce misleading estimates, if the policy's effect is heterogeneous between groups or over time, as is often the case.This survey reviews a fast-growing literature that documents this issue, and that proposes alternative estimators robust to heterogeneous effects.
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A recent literature has identified problems with difference-in-differences designs that rely on the staggered introduction of a program across groups over time.
“A recent literature has identified problems with difference-in-differences designs that rely on the staggered introduction of a program across groups over time (see, e.g., Goodman-Bacon, 2021; de Chaisemartin & D'Haultfoeuille, 2022).”
From College Costs, Financial Aid, and Student Decisions (2022) · cites this paper as de Chaisemartin & D'Haultfoeuille, 2022
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Cites
Difference-in-differences with variation in treatment timing
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Flagged first, then by citations
Research works printed but not linked: 26
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Cited by
Sorted by citations
What's trending in difference-in-differences? A synthesis of the recent econometrics literature
Roth, J., Sant’Anna, P. H. C., Bilinski, A., & Poe, J. (2023) · Journal of Econometrics · doi:10.1016/j.jeconom.2023.03.008 · Cited by 2,027 · see citing works
Two-way fixed effects, the two-way Mundlak regression, and difference-in-differences estimators
Wooldridge, J. M. (2025) · Empirical Economics · doi:10.1007/s00181-025-02807-z · Cited by 139 · see citing works
College Costs, Financial Aid, and Student Decisions
Dynarski, S., Page, L., & Scott-Clayton, J. (2022) · National Bureau of Economic Research · doi:10.3386/w30275 · Cited by 56 · see citing works
- Authors
- de Chaisemartin, C., & D'Haultfoeuille, X.
- Venue
- National Bureau of Economic Research
- Publisher
- National Bureau of Economic Research
- Published
- 2022-01
- OpenAlex
- W4256413215
- Cited by
- 31
- References
- 7
- Citations by year
- 2025: 3 · 2024: 3 · 2023: 19 · 2022: 6
- Type
- report
- Language
- en
- Open access
- green
- doi.org
- Locations
- National Bureau of Economic Research (publishedVersion)
- Topics
- Physical Sciences › Mathematics › Statistics and Probability › Advanced Causal Inference Techniques
- Social Sciences › Economics, Econometrics and Finance › Economics and Econometrics › Spatial and Panel Data Analysis
- Social Sciences › Decision Sciences › Management Science and Operations Research › Evaluation and Performance Assessment
- Keywords
- two-way fixed effects, difference-in-differences, treatment effect heterogeneity, policy evaluation, robust estimators, causal inference
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