In this paper, we are going to reconsider the standard Viner Model [Viner, 1950] however under the premise of firm heterogeneity. By means of a graphical analysis we show that a consideration of the degree of firm heterogeneity is important for an evaluation of a preferential trade agreement....

Recently, discussion about the appropriate estimation of gravity trade models has started in agriculture. Here, we are going to review recent developments in the literature. It appears that fixed effects Poisson Pseudo Maximum Likelihood is not only the only consistent estimator [Santos Silva...