In this paper we show that findings of an apparently instable popularity function of U.S. presidents, as reported in the previous literature, are likely the consequence of the common use of linear estimation techniques. Employing Penalized Spline Smoothing in the context of Additive Mixed Models...

We analyze the spatial interaction among regions in North America and in Western Europe. We use a gravity model extended by a spatial correlation structures where data allows to evaluate the level of impact and the length of the spatial tail. This allows us to address to effects external to the...

We examine the degree of natural gas market integration in Europe, North America and Japan, between the mid 1990's and 2002. The relationship between the international gas marker prices, and their relation to the oil price, are investigated through principal component analysis and Johansen...

The present study examines whether and to what extent welfare-family policies are likely to affect earnings inequality between economically active men and women. Using hierarchical linear models, we combine individual-level variables (obtained from the Luxembourg Income Study) with country level...