Port wine exports: a gravity model approach

Abstract

Purpose The purpose of this paper is to empirically examine the macroeconomic determinants of Port wine exports, taking into account the diversity and various quality levels associated with this product. Design/methodology/approach Port wine is a fortified wine only produced in Portugal. In the period 2006-2014, an extended gravity model is applied to data on the exports of the top 20 importing countries, accounting for 94 per cent of total exports. The authors base their empirical strategy on the Hausman–Taylor estimator (1971), overcoming endogeneity and accounting for time invariant variables. They estimate the impact of several factors on the total trade of Port wine, namely: gross domestic product (GDP), GDP per capita, tariffs, exchange rates, distance from original supplier, mutual language familiarity, landlockedness, wine consumption per capita and presence of Portuguese emigrants, all measured in volume and value terms, and for each of the four categories (Standard, High Standard, Vintage and Aged). Findings The findings show that the quantity and value of total Port wine exports are positively determined by overall GDP per capita, the presence of a Portuguese emigrant community (which implies that to some degree a common language and culture are shared), while exports are negatively influenced by landlockedness. In contrast to the traditional gravity model, distance from the source of supply does not appear to be a significant determinant, a fact explained by the specific and singular nature of Port wine and by the long tradition of this product in international markets. In addition, the results revealed specific determinants for specific product categories – such as GDP for aged Port and wine consumption per capita for high standard, vintage and aged Port, suggesting that Portugal needs to increase its exports of high-quality Port wine to markets that exhibit a tendency towards increased wine consumption per capita and are coming to be considered large and fast-growing economies. Originality/value This paper extends the literature, by respecifying the typical gravity model for aggregate goods to permit the analysis of wine exports. There has been relatively little application of this model to assess the determinants of the wine trade, and when it has been used, generally it has been in studies focusing on aggregate wine trade between countries. This paper seeks to fill this gap by focusing on the determinants of exports of a specific wine – Port wine, which is an internationally recognised product, with a clear internal product differentiation according to distinct quality levels – and in this regard provides new insights into the international patterns of trade in wine.