Optimal Shrinkage Estimation of Fixed Effects in Linear Panel Data Models

Soonwoo Kwon

Econometrica2026https://doi.org/10.3982/ecta22386article
FT50AJG 4*ABDC A*
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0.37

Abstract

Shrinkage methods are frequently used to improve the precision of least squares estimators of fixed effects. However, widely used shrinkage estimators guarantee improved precision only under strong distributional assumptions. I develop an estimator for the fixed effects that obtains the best possible mean squared error within a class of shrinkage estimators. This class includes conventional shrinkage estimators and the optimality does not require distributional assumptions. The estimator has an intuitive form and is easy to implement. Moreover, the fixed effects are allowed to vary with time and to be serially correlated, in which case the shrinkage optimally incorporates the underlying correlation structure. I also provide a method to forecast fixed effects one period ahead in this setting.

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https://doi.org/https://doi.org/10.3982/ecta22386

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@article{soonwoo2026,
  title        = {{Optimal Shrinkage Estimation of Fixed Effects in Linear Panel Data Models}},
  author       = {Soonwoo Kwon},
  journal      = {Econometrica},
  year         = {2026},
  doi          = {https://doi.org/https://doi.org/10.3982/ecta22386},
}

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Optimal Shrinkage Estimation of Fixed Effects in Linear Panel Data Models

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