In regression analysis, classical estimations may be excessively influenced by a few atypical observations. We propose a Hausman-type test to balance robustness and efficiency and to check whether a robust method should be implemented. An economic application is presented.

Using Baltagi and Li (2002)’s semi-parametric fixed effects regression estimator, we investigate the existence of an aggregate ‘Kuznets curve’ in a sample of 113 countries over the 1960–2000 period. Our results show that misspecification of the functional form in a panel model with...