Inmaculada Martínez-Zarzoso

The log of gravity revisited

This article evaluates the performance of alternative estimation methods for gravity models with heteroscedasticity and zero trade values. Both problematic issues, recently addressed by Santos Silva and Tenreyro in an influential paper, are re-examined here. We use Monte Carlo simulations to compare the Pseudo Poisson Maximum Likelihood (PPML) estimator recommended by Santos Silva and Tenreyro, a Gamma Pseudo-Maximum-Likelihood (GPML), a Nonlinear Least Squares (NLS) estimator and a Feasible Generalized Least Squares (FGLS) estimator with more traditional techniques. Additionally, estimates of the gravity equation are obtained for three different data sets with the abovementioned methods. The results of the simulation study indicate that, although the PPML estimator is less affected by heteroscedasticity than others are, its performance is similar, in terms of bias and SEs, to the FGLS estimator performance, in particular for small samples. GPML presents however the lowest bias and SEs in the simulations without zero values. The results of the empirical estimations, using three different samples containing real data, indicate that the choice of estimator has to be made for each specific dataset. It is highly recommended to follow a model selection approach using a number of tests to select the more appropriate estimator for any application.

The Impact of Population on CO2 Emissions: Evidence from European Countries

This paper analyses the impact of population growth on CO2 emissions in European Union countries. Traditionally, researchers have assumed a unitary elasticity of emissions with respect to population growth. In this study population is treated as a predictor in the model, instead of being included as part of the dependent variable (per capita emissions), thus relaxing the above-mentioned assumption of unitary elasticity. We also contribute to the existing literature by taking into account the presence of heterogeneity in the sample and considering a dynamic specification. The sample covers the period 1975-1999 for the current European Union members. Our results show that the impact of population growth on emissions is more than proportional for recent accession countries whereas for old EU members, the elasticity is lower than unity and non significant when the properties of the time series and the dynamics are correctly specified. The different impact of population change on CO2 emissions for the current EU members should therefore be taken into account in future discussions of climate change policies within the EU.

Transport costs and trade: Empirical evidence for Latin American imports from the European union

Abstract This paper aims to investigate the relationship between trade flows and transport costs. In previous studies the cost of transport was considered as an exogenous variable. However, an expanding volume of trade also reduces the unit cost of transport and, therefore, the causal relationship between trade and transport costs may be operating in both directions. A transport-costs equation is estimated using data on transportation costs from the International Transport Data Base (BTI). The relationship between transport costs and trade is then analysed by applying a gravity model for sectoral imports for five Latin American Countries from the European Union. We investigate the endogeneity of the transport cost and trade variables by estimating simultaneously both equations. Our results show that, while higher distance and poor importers infrastructure notably increase transport costs, a higher volume of trade has the opposite effect. Moreover, trade is significantly deterred by higher transport costs and fostered by cultural similarities.

Is distance a good proxy for transport costs? The case of competing transport modes

Abstract In this paper, we analyze separately the determinants of maritime transport and road transport costs for Spanish exports to Poland and Turkey (markets for which maritime and road transport are competing modes) and investigate the different effects of these costs on international trade. First, we investigate the extent to which maritime and road transport costs depend on different factors such as unit values, distances, transport conditions, service structures, and service quality. Second, we analyze the relative importance of road and maritime transport costs in comparison with distance measures as determinants of trade flows. The main results of this investigation indicate that real distance is not a good proxy for transportation costs and identify the central variables influencing road and maritime transportation costs: for both modes, transport conditions are strong determinants, whereas efficiency and service quality are more important for maritime transport costs, and geographical distance is more important for road transport. Road and maritime transport costs are central explanatory factors of exports and they seem to deter trade to a greater extent than road or maritime transit time when endogeneity is considered.

The Impact of a Customs Union between Turkey and the EU on Turkey's Exports to the EU

This article investigates Turkeys sectoral trade flows to the EU based on panel data from the period 1988 to 2002. Turkeys 16 most important export sectors are analysed. Emphasis is placed on the role of price competition, EU protection and transport costs in the export trade between Turkey and the EU. The empirical model used is an extended version of the gravity model. This study is also a contribution to the current discussion of whether Turkey should be granted full EU membership or a privileged partnership with the EU, which for Turkey would mean improved access to the EU market for its products, among other benefits. Our investigation focuses on the latter policy outcome: the impact of deepening the customs union between Turkey and the EU and applying the common agricultural policy (CAP) to Turkish agricultural exports. To this end, the impact of the 1996 customs union covering most industrial goods and processed agricultural goods, is evaluated on a sectoral level. We also perform simulations to quantify the impact of the potential inclusion of agricultural goods, as well as iron and steel and products thereof, into the full customs union between Turkey and the EU which is still to come.

Does foreign aid really raise per capita income? A time series perspective

We analyze the relationship between per capita income and foreign aid. We employ annual data and five‐year averages and carefully examine the time‐series properties of the data. Panel estimations with dynamic feasible generalized least‐squares (DFGLS) show that aid generally has an insignificant or minute negative significant impact on per capita income (particularly in highly aid‐dependent countries). This holds true for countries with different levels of human development and income, as well as for different regions. We also find that aid has a small positive impact on investment, but a significant negative impact on domestic savings (crowding out) and the real exchange rate (appreciation). (On analyse la relation entre le revenu per capita et l’aide etrangere. On utilise des donnees annuelles et des moyennes quinquennales, et on examine les proprietes de ces series chronologiques. Des estimations d’un modele dynamique utilisant des donnees de panel a l’aide de la methode des moindres carres quasi‐generalises montrent que l’aide a generalement un effet negatif minime ou insignifiant sur le revenu per capita (particulierement dans les pays qui dependent beaucoup de l’aide etrangere). Ce resultat tient tant pour des pays a divers niveaux de developpement et de revenus que pour differentes regions. On decouvre que l’aide a un petit effet positif sur l’investissement, mais un effet negatif significatif sur l’epargne (effet d’encombrement) et sur le taux de change reel (appreciation).)

The Effect of Trade Facilitation on Sectoral Trade

Abstract This paper aims to analyse the effect of trade facilitation on sectoral trade flows. We use data from the World Banks Doing Business Database on the fees associated with completing the procedures to export or import goods in a country, on the number of documents needed and on the required time to complete all the administrative procedures to import and export. An augmented gravity equation is estimated for 13 exporters and 167 importers using a number of estimation techniques, namely OLS, PPML and the Harvey model. A common result is that trade flows increase by lowering transport costs and the number of days required to trade. The outcome supports multilateral initiatives, as that in the WTO, which encourages countries to assess their trade facilitation needs and priorities and to improve them. The measures adopted will not only benefit the country that improves trade facilitation, but also its trading partners.

Aid and Trade - A Donor's Perspective

Abstract One reason donors provide foreign aid is to support their exports to aid-recipient countries. Time series data for Germany suggests an average return of between US

Does Foreign Aid Really Raise Per Capita Income? A Time Series Perspective (Est‐Ce Que L’Aide Étrangère Augmente Vraiment Le Revenu Per Capita? Une Approche Par Les Séries Chronologiques)

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Economic Growth and CO2 Emissions in the European Union

1.50 for each US dollar of aid spent by Germany. Although this is well below previous estimates, the value is robust to different specifications and econometric approaches. Interestingly, we find strong evidence of crowding out between bilateral donors in the sense that bilateral aid from other EU members significantly reduces exports from Germany to the recipients. The evidence suggests that, in the long run, aid causes exports and not vice versa. We discuss the implications these findings might have for aid volumes and allocation.