This paper considers alternative methods to estimate econometric models based on bilateral data when only aggregate information on the dependent variable is available. Such methods can be used to obtain an indication of the sign and magnitude of bilateral model parameters and, more importantly, to decompose aggregate into bilateral data, which can then be used as proxy variables in further empirical analysis. We perform a Monte Carlo study and carry out a simple real world application using intra-EU trade and capital flows, showing that the methods considered work reasonably well and are worthwhile being considered in the absence of bilateral data. (authors' abstract) / Series: Department of Economics Working Paper Series

Thesis advisor: James E. Anderson / The gravity model proved to to be one of the most successful framework for analyzing international trade flows, being referred to as the “workhorse” in the international trade literature (Head and Mayer (2014)). Microfoundations to this model has been provided in Anderson (1979) and it has often been employed to estimate the effects of a variety of trade policies (see Cipollina and Salvatici (2010) for a meta-analysis on reciprocal trade agreements, Rose (2000) for the effects of currency unions). The two chapters of this dissertation, which are independent empirical pieces, both make use of gravity equations for the estimation of trade flows, although with different purposes. The first chapter focuses on the specification of the gravity equation. In the second chapter, instead, gravity equations are employed for assessing the relationship between trade and growth: in fact, their estimation represents the first step for the creation of an instrumental variable for export flows. In the first chapter, a solo-authored work titled Scale Economies in European Trade, I show that European data support the existence of economies of scale in trade flows. The impact of trade costs on trade flows, in fact, is assumed to be constant by almost all empirical studies employing the gravity framework. Anderson et al. (2016) are the first to depart from this assumption, allowing trade costs to vary as a function of trade volumes. Their model nests the more traditional one and hence can be used to test for the existence of these scale economies, which are shown to be in place for trade between US and Canada. For my analysis I construct a comprehensive dataset for European trade in manufacturing over a long time span (from 1980 to 2013), on which I employ the same methodology. My results show that scale economies in trade costs are indeed a strong empirical fact outside of the American continent, and this holds for all the 26 manufacturing sectors considered, with an estimated average of 0.64% decrease in trade costs given by a 10% increase in trade volume. The focus on Europe allows me to test whether the EU expansion affected these economies of scale. While this is not true on average, it seems to be the case for some industries: trade with a EU partner entails scale elasticities 50% lower than trade with a non-EU member for 11 sectors out of the 26 considered. I also investigate whether scale elasticities can be rationalized by the existence of informational asymmetries. Using detailed product-level data, I do not find evidence that the degree of product homogeneity can account for the observed cross-sectoral variation. The scale coefficients are instead linked to country-specific institutional variables, such as the level of corruption: exporting to the country whose level of corruption is the lowest in the sample entails half the scale elasticity than exporting to the most corrupted one. In other words, corruption depresses trade to an higher extent on longer distances. In the second chapter, joint with Carlo Altomonte and Italo Colantone and titled Trade and Growth in the Age of Global Value Chains, we revisit the relationship between trade and income, taking into account the recent surge of global value chains (GVCs). First, we develop a new geography-based, time-varying instrument for export, exploiting the sharp increase (almost tripling) in the maximum size of container ships between 1995 and 2007. This global shock has an asymmetric impact on bilateral trade flows across countries, affecting disproportionately more countries endowed with a larger number of deep-water ports, which are needed to accommodate the new, much larger ships. We exploit this heterogeneity for identification, building up the instrument for export in a gravity framework. Our result show that export has a positive effect on GDP per capita, with a 0.6 elasticity. Evidence at the country-level shows that this effect works through capital accumulation. Exploiting the decomposition methodology by Wang et al. (2013), we show that differences in the value added composition of exports matter for trade-growth nexus. We find evidence in favor of an income premium for countries that upgrade their positioning in GVCs, whereas the degree of participation to GVCs does not seem to play a role. Consistent with this finding, we show that countries whose average level of upstreamness (a’ la Antras and Chor (2013)) increases the most over time exhibit a higher trade elasticity of income. Both papers indirectly deal with the effect of geographical distance on international trade flows. One of the strongest regularities in economics is certainly the negative role played on trade flows by the distance between origin and destination. Disdier and Head (2004), comparing 1,467 different studies, compute an average distance elasticity of trade of about -0.9. Hummels (2007) shows that the distance elasticity of trade does not seem to diminish over time, as it would do should distance be capturing only transportation costs, thanks to the technological developments witnessed in the transportation sector. Distance seems then to refer to trade costs in general, including institutional, policy and regulatory barriers that, also for historical reasons, often increase the further away countries are located. In the first paper, I show that the impact of distance on trade flows is not constant but varies with trade volumes. This corresponds with having a component of the composite friction described before, hidden in the distance term, being fixed and is consistent with micro-evidence on the export behavior obtained from firm-level data (Roberts and Tybout (1997)). It seems natural, then, to test whether some characteristics, either at the product-level or at the country-level, have a prominent role in explaining the non-linear effect that distance has on trade. My results find in level of corruption of the destination country an important determinant. In the second paper, we test whether the distance elasticity of trade varies as a function of the number of deep water ports on both the importer’s and the exporter’s shores, capturing the extent to which countries can trade via container vessels. The data support this claim for all the manufacturing sectors considered, showing that geographical distance, even though non-exclusively, captures the incidence of transportation costs on export flows. / Thesis (PhD) — Boston College, 2016. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.

This paper considers alternative methods to estimate econometric models based on bilateral data when only aggregate information on the dependent variable is available. Such methods can be used to obtain an indication of the sign and magnitude of bilateral model parameters and, more importantly, to decompose aggregate into bilateral data, which can then be used as proxy variables in further empirical analysis. We perform a Monte Carlo study and carry out a simple real world application using intra-EU trade and capital flows, showing that the methods considered work reasonably well and are worthwhile being considered in the absence of bilateral data. (authors' abstract)

Cette thèse vise à contribuer aux récents débats sur les avantages potentiels de l'ouverture commerciale entre les pays Africains. Elle le fait en abordant la triptyque Accords Régionaux de Commerce(ACRs), bien-être et conflits.Le continent Africain fait face aujourd’hui à deux enjeux majeurs de gouvernance : l’intégration régionale et la gestion des conflits armés. En effet, les performances commerciales des pays africains restent toujours marginales comparativement au reste du monde. Et ce, malgré les différentes politiques commerciales mises en œuvre depuis les années 70 (politique d'import-substitution, accord régional nord-sud, etc.…). Parmi ces politiques commerciales, les gouvernements Africains ont décidé de privilégier les accords régionaux en vu d’accroître le commerce entre les pays membres. Ces accords ont-ils eu l'effet escompté ? Dans quelle mesure ?Si on se réfère au point de vue largement partagé, la réponse semble être négative. Cependant cette réponse ignore les bénéfices politiques potentiels de l'ouverture commerciale. A ce titre, le travail présenté ici étudie l'effet des accords régionaux africains sur le commerce et le bien-être. Cela en utilisant les derniers développements de la théorie du commerce international ainsi que les meilleures techniques d'estimations des équations de gravité. Deuxièmement, Nous analysons l'effet de l'augmentation du commerce sur la probabilité de survenance d'une guerre civile à la fois de façon théorique et empirique. Les résultats obtenus, nous permettent de conclure que sans la signature des ACRs, près de la moitié des échanges entre leurs membres n'auraient pas été réalisé. D'autre part, cette thèse affirme que le commerce, à la fois domestique et international permet de diminuer le risque de conflit civil en Afrique. / This thesis aims to contribute to recent debates on the potential benefits of trade openness among African countries. This, by addressing the triptych regional trade agreements, welfare and conflict.The African continent is currently facing two major governance challenges: regional integration and the management of armed conflicts. Indeed, the trade performance of African countries remains marginal compared to the rest of the world. This is despite the different trade policies implemented since the 1970s (import substitution policy, North-South regional agreement, etc.). Among these trade policies, African governments have decided to focus on regional agreements in order to increase trade among member countries. Have these agreements had the expected effect ? To what extent ?If we refer to popular belief, the answer seems to be no. However, this answer ignores the potential political benefits of trade openness. As such, the work presented here first examines the effect of African regional agreements on trade and welfare. This is done using the latest developments in international trade theory and the best techniques for estimating gravity equations. Second, we analyze both theoretically and empirically the effect of increased trade on the probability of a civil war occurring. The results obtained allow us to conclude, on the one hand, that nearly half of the trade between members of trade agreements in Africa would not have been possible without the signing of the RTAs. On the other hand, both domestic and international trade, reduces the risk of civil conflict in Africa.

The purpose of this thesis is to implement the gravity model approach to identify and quantify determinants of bilateral trade flows of Germany and its trading partners, while focusing on the effect of institutions. Based on various gravity model techniques (clustered pooled OLS, Poisson Pseudo-Maximum Likelihood estimation, Hausman and Taylor estimation and Instrumental Variables regression), we have confirmed that the quality of institutions have a signifiant and positive effect on German exports. Depending on model specification and estimation technique, some institutions seem to effect German export more than others. We see the Hausman and Taylor estimator advisable for addressing endogeneity of institutions.

Cette thèse s’attache à contribuer aux débats actuels quant aux possibles avantages des marchés de l’eau. De par les changements économiques et une croissante instabilité climatique, bon nombre de régions arides à travers le monde doivent reconsidérer leur stratégie de gestion de leurs ressources hydrologiques. Une préférence substantielle envers des mécanismes de réallocation plus flexible telle que les marchés de l’eau y est portée pour limiter le stress hydrique. Bien qu’efficients en théorie, ces instruments sont aussi très coûteux, autant dans leurs mises en place que dans leur maintenance, à cause principalement des possibles externalités que des transferts d’eau peuvent induire. Ces coûts de transaction limitent l’efficacité des marchés de l’eau en comparaison à une situation de concurrence pure et parfaite et peuvent être plus dommageables qu’une gestion centralisée. Ainsi, toutes analyses d’une décentralisation de la gestion des ressources en eau doivent prendre en compte ces coûts de transaction. A ce titre, le travail présenté ici étudie les causes sous-jacentes à ces coûts de transactions et adapte un outil déjà largement utilisé dans le cadre du commerce international : les équations de gravité. L’application de ce modèle aux marchés de l’eau en Californie permet de mettre en évidence et de mesurer l’importance de ces coûts de transactions dans le développement de tels instruments de gestion de l’eau. / This dissertation aims at contributing to the ongoing debate about the potential effectiveness of water markets. With the ongoing economic changes and the growing versatility of water resources due to climate changes, many arid regions around the world need to reconsider their strategy of managing their hydrological resources. Interests among policy makers are leaning toward flexible reallocation mechanisms such as water markets to cope with water shortages. While efficient in theory, such instruments are also very costly to establish and to maintain because of the potential externalities that transferring water may cause. These so-called transaction costs limit the effectiveness of water markets in comparison to the situation of perfect competition and can induce a more detrimental outcome than a centralized management. Therefore, any decentralized solutions to manage the scarce water resources must account for the transaction costs of running such alternatives. In that respect, this work focuses on studying the underlying causes of these transaction costs and adapts a tool widely used in the international trade economics: the gravity equations. Through that way, importance of these transaction costs for the development of effective water markets is reasserted. More importantly, a theoretical and empirical model is developed to measure the magnitude of the different frictions in reallocating water through decentralized managements in the case of California.

Cette thèse rassemble principalement des contributions en économie de la science à laquelle les deux premières parties sont consacrées. La première teste l'importance des choix méthodologiques dans la mesure de la production scientifique et étudie les canaux de diffusion de la connaissance. La deuxième s'intéresse aux déterminants individuels et locaux de la productivité des chercheurs et au différentiel de promotion entre hommes et femmes sur le marché du travail académique. Sont établis les résultats suivants : les choix méthodologiques dans la mesure de la production scientifique n'affectent que très peu les classements des institutions de recherche. Les citations et les poids associés à la qualité des journaux mesurent globalement la même productivité de la recherche. La localisation des chercheurs a un impact sur leur productivité dans la mesure où certaines universités génèrent davantage d'externalités que d'autres. Ces externalités sont plus importantes là où les chercheurs sont homogènes en terme de performances, où la diversité thématique est grande, et dans une moindre mesure dans les grands centres de recherche, lorsqu'il y a plus de femmes, de chercheurs âgés, de stars et là où les chercheurs sont connectés à des co-auteurs à l'étranger. Si les femmes sont moins souvent Professeur des Universités (par opposition à Maître de Conférences) que les hommes, ce n'est ni parce qu'elles sont discriminées dans le processus de promotion, ni que le coût de promotion (mobilité) est plus important pour elles, ni qu'elles ont des préférences différentes concernant le salaire et le prestige des institutions dans lesquelles elles travaillent. / The core of this thesis lies in the field of economics of science to which the two first parts are devoted. The first part questions the impact of methodological choices in the measurement of research productivity and studies the channels of knowledge diffusion. The second part studies the impact on individual publication records of both individual and departments' characteristics and analyse the gender gap in occupations on the academic labour market. The main results are the following: methodological choices in the measurement of research productivity do not impact the estimated hierarchy of research institutions. Citations and journal quality weights measure the same dimension of publication productivity. Location matters in the academic research activity: some departments generate more externalities than others. Externalities are higher where academics are homogeneous in terms of publication performance and have diverse research fields, and, to a lower extent, if the department is large, with more women, older academics, stars and co-authors connection to foreign departments. If women are less likely to be full Professor (with respect to Assistant Professor) than men, this is neither because they are discriminated against in the promotion process, neither because the promotion cost (mobility) is higher for them, nor because they have different preferences for salaries versus department prestige. A possible, but not tested, explanation is that women self-select themselves by participating less in or exerting lower effort during the promotion process.

La production locale des huiles alimentaires ne constitue plus une ligne de défense crédible face aux importations dans les pays de l’UEMOA. Cette réalité contraste avec les objectifs de la politique agricole et du tarif extérieur commun (TEC) de l’UEMOA censés protéger la production communautaire. Ainsi, sous l’éclairage de la littérature économique et en se basant sur des données empiriques, nous avons utilisé les équations simultanées par pays de l’UEMOA, les équations des données de panel et les équations gravitationnelles en données de panel pour déterminer l’impact de la libéralisation commerciale sur l’offre des huiles alimentaires dans les pays de l’UEMOA.Les résultats obtenus convergent vers une même conclusion : la confrontation des objectifs de protection de la production communautaire et d’ouverture commerciale aux tests de cohérence révèle des incohérences et des contradictions. Les politiques de libéralisation commerciale ont plutôt favorisé une déstructuration du tissu productif et une désorganisation de l’architecture commerciale. De facto, l’offre des huiles alimentaires affiche deux réactions contradictoires au regard de la libéralisation commerciale au sein des pays de l’UEMOA : une réaction dépressive affichée par la production qui plombe et une réaction explosive affichée par les importations qui flambent et qui sont attirées par des rentes de réexportation. Cependant, ces rentes constituent des mirages qui réservent des implications économiques aux conséquences destructrices avec l’adoption du TEC-CEDEAO. / Local production of edible oils in the WAEMU’s countries is no longer a credible defense line against imports. This reality contrasts with the objectives of agriculture policy and WAEMU’s Common External Tariff (CET) which are supposed to protect Community production. Thus, under the light of the economic literature and based on empirical data, we used simultaneous equations for each country of WAEMU, panel data and gravity equations with panel data to determine the impact of trade liberalization on supply of edible oils in WAEMU’s countries.The results obtained converge towards the same conclusion: the confrontation of objectives of protecting local production and trade openness policy with the coherence’s tests reveals some inconsistencies and contradictions. Thus, WAEMU fails to reconcile the Union's trade openness objectives with the protection objectives of edible oils producers. Trade liberalization policies have tended to favor a disintegration of the productive structure and disruption of trade architecture. Thus, the supply of edible oils shows two contradictory reactions with regard to the trade liberalization within the WAEMU’s countries: a depressive reaction displayed by the production and an explosive reaction displayed by the imports which are attracted by re-export rents. However, these rents are mirages that reserve destructive economic implications with the adoption of ECOWAS’CET.