Modelo gravitacional aplicado a bens agrícolas: o caso das exportações brasileiras de açúcar

Abstract

This work aims to analyze the evolution and methodological alternatives of the quanti- tative method called “gravitational model of international trade”, when applied to help explain the trade of agricultural goods. Agricultural goods have specific features in their production processes, associated with locations and production factors, especially land and weather conditions. Therefore, they cannot be treated in the same way as manufactured goods, which can have their production process and production factors allocated and relocated to any part of the globe, allowing for a better adjustment of production processes, as recommended by the international division of labor. The greater rigidity of production factors for agricultural goods is a characteristic described in international trade theory and which has been relegated in the application of the gravitational model, reducing the explanatory capacity of the model when applied and, consequently, increasing the possibility of incurring in trade errors. magnitude, statistical significance and interpretation of marginal effects when assessing which and how much factors impact unilateral or bilateral trade flows. The first part of this work makes a historical and theoretical survey of the gravitational model, its different applications and the adaptations adopted to encompass the various characteristics of international trade, whether the production process, legislation, trade agreements, transport costs, among others . The research covers more than 50 years of history, from the emergence of the model, its evolution process and its consolidation as an analytical tool. The second part consists of a literature review of works that applied the model to the analysis of international trade specifically to agricultural goods, focusing on the pattern of method- ological adaptations - when there were -, and on the justifications for these adaptations. In the last part of this work, a methodological proposal is made, derived from the factor endowment model, which can be used in the application of the model in the study of unilateral or bilateral trade in agricultural goods, including variables that minimally reflect the nature of the agricultural process and that are aligned with regard to specific factors for the analysis of international trade. The conclusion is unfavorable to the application of the gravitational model for agricultural goods, there is no convergence in the literature for the adoption of characteristics of these products. Statistical problems such as the one-sidedness of flows, the absence of trade in specific periods, as well as the presence of zero or null values reduce the robustness of the model.