Quotation Plümper, Thomas, Troeger, Vera. 2019. Not so harmless after all. The Fixed Effects Model. Political Analysis. 27 (1), 21-45.




The fixed-effects estimator is biased in the presence of dynamic misspecification and omitted within variation correlated with one of the regressors. We argue and demonstrate that fixed-effects estimates can amplify the bias from dynamic misspecification and that with omitted time-invariant variables and dynamic misspecifications, the fixed-effects estimator can be more biased than the ‘naïve’ OLS model. We also demonstrate that the Hausman test does not reliably identify the least biased estimator when time-invariant and time-varying omitted variables or dynamic misspecifications exist. Accordingly, empirical researchers are ill-advised to rely on the Hausman test for model selection or use the fixed-effects model as default unless they can convincingly justify the assumption of correctly specified dynamics. Our findings caution applied researchers to not overlook the potential drawbacks of relying on the fixed-effects estimator as a default. The results presented here also call upon methodologists to study the properties of estimators in the presence of multiple model misspecifications. Our results suggest that scholars ought to devote much more attention to modeling dynamics appropriately instead of relying on a default solution before they control for potentially omitted variables with constant effects using a fixed-effects specification.


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Publication's profile

Status of publication Published
Affiliation WU
Type of publication Journal article
Journal Political Analysis
Citation Index SSCI
Language English
Title Not so harmless after all. The Fixed Effects Model
Volume 27
Number 1
Year 2019
Page from 21
Page to 45
Reviewed? Y
DOI http://dx.doi.org/10.1017/pan.2018.17
Open Access N


Plümper, Thomas (Details)
Troeger, Vera (University of Warwick, United Kingdom)
Institute for Sociology and Social Research IN (Details)
Research areas (ÖSTAT Classification 'Statistik Austria')
5118 Political science (Details)
5325 Political economics (Details)
5912 Social sciences (interdisciplinary) (Details)
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