In regression and multivariate analysis, the presence of outliers in the dataset can strongly distort classical estimations and lead to unreliable results. To deal with this, several robust-to-outliers methods have been proposed in the statistical literature. In Stata, some of these methods are...

When some observations are outlying (in one or several dimensions) PCA is distorted an may lead to incorrect results. We therefore propose a simple solution to deal with this problem by providing a short ado file. To illustrate the importance of outliers in PCA I would like to present a simple...

In the robust statistics literature, a wide variety of models has been developed to cope with outliers in a rather large number of scenarios. Nevertheless, a recurrent problem for the empirical implementation of these estimators is that optimization algorithms generally do not perform well when...

Semiparametric regression deals with the introduction of some very general nonlinear functional forms in regression analyses. This class of regression models is generally used to fit a parametric model in which the functional form of a subset of the explanatory variables is not known and/or in...

From the literature on decentralization, it appears that the fiscal vertical imbalance is somehow inherent to multi-level governments. Using a stylized model we show that this leads to a reduction in the extent of redistributive fiscal policies if the maximal tolerable size of government has...

In this article we use the high-quality data coming from the Luxembourg Income Study Project, in a panel framework, to test for the effects of electoral systems on both poverty and income inequality. We find that when de degree of proportionality of an electoral system increases, inequality and...

Summary In empirical studies often the values of some variables for some observations are much larger or smaller than the values for the other observations in the sample. These extreme observations, or outliers, often have a large impact on the results of statistical analyses. Conclusions based...