Design-Robust Two-Way-Fixed-Effects Regression For Panel Data

Fuente: arXiv
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Autores principales: Arkhangelsky, Dmitry, Imbens, Guido W., Lei, Lihua, Luo, Xiaoman
Formato: Preprint
Publicado: 2021
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author Arkhangelsky, Dmitry
Imbens, Guido W.
Lei, Lihua
Luo, Xiaoman
author_facet Arkhangelsky, Dmitry
Imbens, Guido W.
Lei, Lihua
Luo, Xiaoman
contents We propose a new estimator for average causal effects of a binary treatment with panel data in settings with general treatment patterns. Our approach augments the popular two-way-fixed-effects specification with unit-specific weights that arise from a model for the assignment mechanism. We show how to construct these weights in various settings, including the staggered adoption setting, where units opt into the treatment sequentially but permanently. The resulting estimator converges to an average (over units and time) treatment effect under the correct specification of the assignment model, even if the fixed effect model is misspecified. We show that our estimator is more robust than the conventional two-way estimator: it remains consistent if either the assignment mechanism or the two-way regression model is correctly specified. In addition, the proposed estimator performs better than the two-way-fixed-effect estimator if the outcome model and assignment mechanism are locally misspecified. This strong double robustness property underlines and quantifies the benefits of modeling the assignment process and motivates using our estimator in practice. We also discuss an extension of our estimator to handle dynamic treatment effects.
format Preprint
id arxiv_https___arxiv_org_abs_2107_13737
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Design-Robust Two-Way-Fixed-Effects Regression For Panel Data
Arkhangelsky, Dmitry
Imbens, Guido W.
Lei, Lihua
Luo, Xiaoman
Econometrics
General Economics
Economics
Methodology
We propose a new estimator for average causal effects of a binary treatment with panel data in settings with general treatment patterns. Our approach augments the popular two-way-fixed-effects specification with unit-specific weights that arise from a model for the assignment mechanism. We show how to construct these weights in various settings, including the staggered adoption setting, where units opt into the treatment sequentially but permanently. The resulting estimator converges to an average (over units and time) treatment effect under the correct specification of the assignment model, even if the fixed effect model is misspecified. We show that our estimator is more robust than the conventional two-way estimator: it remains consistent if either the assignment mechanism or the two-way regression model is correctly specified. In addition, the proposed estimator performs better than the two-way-fixed-effect estimator if the outcome model and assignment mechanism are locally misspecified. This strong double robustness property underlines and quantifies the benefits of modeling the assignment process and motivates using our estimator in practice. We also discuss an extension of our estimator to handle dynamic treatment effects.
title Design-Robust Two-Way-Fixed-Effects Regression For Panel Data
topic Econometrics
General Economics
Economics
Methodology
url https://arxiv.org/abs/2107.13737