The Mistreated Model: Some Technical Comments on Porojan's Paper on 'Trade Flows and Spatial Effects'

The paper by Porojan on 'Trade flows and spatial effects' in a recent issue of this journal is criticized on three methodological grounds: it includes two of the gravity model independent variables as relative rather than absolute numbers; the dummy variables included are not binary but interval; and the 'sample' of countries creates a non-normal distribution of inter-country distances, undoubtedly creating heteroscedasticity problems. Because of these three problems, the model is mis-specified, and the results thereby obtained are unreliable.     

区域贸易安排的保护性:引力模型

通过2000-2005年EU、APEC、NAFTA三个区域贸易组织双边贸易流量基于合并数据的引力模型得出结论:三个区域贸易组织的净贸易效果均为贸易转移,但区域保护程度顺次减弱。总体上,发生贸易转移的方向从以发达国家为主的区域贸易组织转移到以新兴市场国家为主或由发达国家与发展中国家共同组成的区域贸易组织。因而,对内积极推行自由贸易,对外具有很强的贸易保护倾向是各国推行区域贸易政策的显著特征。     

Does Gravity Matter in a Service Economy?

This paper estimates gravity equations for bilateral services trade in a sample of 28 countries. It finds that the standard gravity variables of economic size and geographic proximity are significant factors in services trade. It also reveals positive effects of linguistic ties on services trade. There is evidence of a positive link between regional trade arrangements and services trade. Much of that effect appears to reflect the impact of bilateral goods trade on services trade. This implies that efforts to enhance goods trade—bilateral or multilateral—should lead to more services trade as well. JEL no. F13, F15, L80     

Exploring the Intensive and Extensive Margins of World Trade

World trade evolves at two margins. Where a bilateral trading relationship already exists it may increase through time (intensive margin). But trade may also increase if a trading bilateral relationship is newly established between countries that have not traded with each other in the past (extensive margin). We provide an empirical dissection of post–World War II growth in manufacturing world trade along these two margins. We propose a “corner-solutions version” of the gravity model to explain movements on both margins. A Tobit estimation of this model resolves the so-called “distance puzzle”. It also finds more convincing evidence than recent literature that WTO-membership enhances trade. JEL no. F12, F15     

闽台农产品贸易流量和潜力分析

内容以贸易引力模型为基础,结合实际情况加入解释变量建立模型,定量分析闽台农产品贸易状况。通过对模型的实证检验,得出影响闽台农产品贸易流量的主要因素有GDP总量、人均GDP、FDI,在此基础上预测了两地农产品贸易潜力,得出闽台目前存在\"贸易不足\",双方存在较大贸易潜力的结论,并提出相关建议。     

New Borders and Trade Flows: A Gravity Model Analysis of the Baltic States

The objective of this paper is to provide evidence on the effects of an economic and political union by studying the trade flows of the three Baltic countries of Estonia, Latvia and Lithuania after the breakup of the Soviet Union. We specify and estimate a gravity model of exports for the Nordic countries which enables us to determine the size and direction of trade flows in the Baltic states had they not been affected by the political institutions of the Soviet Union. Our results suggest that Baltic foreign trade was not only reduced significantly but also diverted to the members of the former Soviet Union. Consistent with our estimates, we also find that these consequences of the former political union are quickly dissipating, and the Baltic countries are increasing their share of exports to the European Union and the U.S.     

What has determined the rapid post-war growth of intra-EU trade?

Based on the gravity model by Baier and Bergstrand (2001), we use a static and dynamic panel approach to estimate the determinants of the growth of intra-EU trade from 1960 to 2000. The results suggest that income growth was the major force, accounting for approximately two-thirds of total growth. Trade liberalization still had a sizeable effect, while other factors had only a little impact (income convergence, real effective exchange rate changes) or played no role (trade costs). Our estimation results for intra-EU trade, using a variety of extensions, underline the robustness of the Baier-Bergstrand cross-section findings for world trade. JEL no. C23, F12, F14, F15     

Trade Flows and Spatial Effects: The Gravity Model Revisited

This article revisits the popular gravity model of trade in light of the increasingly acknowledged findings of spatial econometrics and interprets the results in view of some recent theoretical developments from the economic literature that contribute to its foundation. When the inherent spatial effects are explicitly taken into account, the magnitude of the estimated parameters changes considerably and, with it, the measures on the predicted trade flows. This result is illustrated for the case of predicted trade flows between the European Union and some of its potential members.