Publications des chercheurs de PSE

A recent literature has used a historical perspective to better understand fundamental questions of urban economics. However, a wide range of historical documents of exceptional quality remain underutilised: their use has been hampered by their original format or by the massive amount of information to be recovered. In this paper, we describe how and when the flexibility and predictive power of machine learning can help researchers exploit the potential of these historical documents. We first discuss how important questions of urban economics rely on the analysis of historical data sources and the challenges associated with transcription and harmonisation of such data. We then explain how machine learning approaches may address some of these challenges and we discuss possible applications.

We propose an integrated framework to discuss the empirical literature on the local determinants of agglomeration effects. We start by presenting the theoretical mechanisms that ground individual and aggregate empirical specifications. We gradually introduce static effects, dynamic effects, and workers' endogenous location choices. We emphasise the impact of local density on productivity but we also consider many other local determinants supported by theory. Empirical issues are then addressed. Most important concerns are about endogeneity at the local and individual levels, the choice of a productivity measure between wage and TFP, and the roles of spatial scale, firms' characteristics, and functional forms. Estimated impacts of local determinants of productivity, employment, and firms' locations choices are surveyed for both developed and developing economies. We finally provide a discussion of attempts to identify and quantify specific agglomeration mechanisms.

Economic Geography" is the most complete, up-to-date textbook available on the important new field of spatial economics. This book fills a gap by providing advanced undergraduate and graduate students with the latest research and methodologies in an accessible and comprehensive way. It is an indispensable reference for researchers in economic geography, regional and urban economics, international trade, and applied econometrics, and can serve as a resource for economists in government."Economic Geography" presents advances in economic theory that explain why, despite the increasing mobility of commodities, ideas, and people, the diffusion of economic activity is very unequal and remains agglomerated in a limited number of spatial entities. The book complements theoretical analysis with detailed discussions of the empirics of the economics of agglomeration, offering a mix of theoretical and empirical research that gives a unique perspective on spatial disparities. It reveals how location continues to matter for trade and economic development, yet how economic integration is transforming the global economy into an economic space in which activities are performed within large metropolitan areas exchanging goods, skills, and information."Economic Geography" examines the future implications of this evolution in the spatial economy and relates them to other major social and economic trends. It provides a complete introduction to economic geography and explains the latest theory and methodologies. It covers the empirics of agglomeration, from spatial concentration measurement to structural estimations of economic geography models. It includes history and background of the field and serves as a textbook for students and a resource for professionals.

Cet article exploite une base de données unique relative à la valeur ajoutée, l'emploi et la population de l'ensemble des départements français pour les années 1860, 1930 et 2000. Ces données concernent trois secteurs : l'agriculture, l'industrie et les services. On peut ainsi étudierl'évolution séculaire des disparités internes à l'espace économique français et tester la validité des prédictions de l'économie géographique. Si l'industrie et les services se sont concentrés entre 1860 et 1930, ils se sont dispersés durant la période 1930-2000, confirmant l'existence d'une courbe en cloche du développement spatial. En revanche, la productivité du travail n'a cessé de converger à l'échelle des départements, ce qui suggère une péréquation spatiale croissante des revenus primaires. Enfin, notre analyse confirme l'existence, à toutes les époques, de fortes économies d'agglomération. Le potentiel marchand durant la première sous-période et le niveau de capital humain durant la seconde expliquent la distribution spatiale de ces gains.

Cet article a pour objectif d'évaluer la sensibilité d'une inférence statistique spatiale au choix du zonage géographique d'étude, et en particulier à la taille et à la forme des unités spatiales choisies (régions, départements, zones d'emploi, rectangles, zonages aléatoires). L'évaluation des distorsions associées au "Problème des Unités Spatiales Modifiables" ou "Modifiable Areal Unit Problem" (MAUP) est effectuée dans le cadre de trois exercices considérés comme standards en économie géographique : la mesure de la concentration spatiale, l'évaluation des gains de productivité engendrés par l'agglomération des activités économiques et l'estimation d'une équation gravitaire de commerce. Si la taille des unités spatiales affecte légèrement les résultats de ces trois inférences statistiques, leur forme compte peu en revanche. Les variations induites par le MAUP sont cependant négligeables en comparaison de celles occasionnées par des changements de spécifications économétriques.

Cet article évalue le rôle positif joué par les résidents français nés à l'étranger sur le commerce international du département d'accueil avec leur pays d'origine. En moyenne, les immigrés facilitent d'autant plus les échanges avec leur pays d'origine que ce dernier dispose de mauvaises institutions (règles de non droit). Cette interaction est particulièrement visible pour les importations de produits homogènes. L'importation des biens différenciés, dont l'échange requiert plus d'information, est favorisée par les immigrés indépendamment de la qualité des institutions du pays d'origine. En ce qui concerne les exportations, les migrants pallient la faiblesse des institutions, aussi bien pour le commerce des biens homogènes que pour celui des produits différenciés.

This paper evaluates, in the context of economic geography estimates, the magnitude of the distortions arising from the choice of a specific zoning system, which is also known as the Modifiable Areal Unit Problem (MAUP). We undertake three standard economic geography exercises (the analysis of spatial concentration, agglomeration economies, and trade determinants), using various French zoning systems differentiated according to the size and shape of their spatial units. While size might matter, especially when the dependent variable of a regression is not aggregated in the same way as the explanatory variables and/or the zoning system involves large spatial units, shape does so much less. In any case, both dimensions are of secondary importance compared to specification issues.

Measures of urban productivity are typically positively associated with city population. But is this relationship causal? We discuss the main sources of bias in the proper identification of agglomeration effects. We also assess a variety of solutions that have been proposed in the literature to deal with them.

This paper studies the evolution and determinants of spatial inequalities in France. To this end, we use a unique database providing data on value-added, employment, and population over the entire set of French "Départements" in 1860, 1896, 1930, 1982, and 2000. These data cover three sectors: Agriculture, Manufacturing, and Services. Firstly, we confirm the existence of a bell-shaped process of spatial concentration in Manufacturing and Services over time. In contrast, labor productivity has been converging across departments. Secondly, we find considerable agglomeration economies over the whole period. The spatial distribution of these gains is determined mainly by market potential in the first sub-period, 1860-1930, and higher education in the second, 1930-2000.

This paper evaluates the role of competition and input-output market access in shaping the geography of economic activity. In a first step, we develop a multi-region multi-industry economic geography model under Cournot competition, of which we estimate the parameter values from French data. We then turn to simulations to see whether a core-periphery equilibrium exists, even with strategic interactions among firms. We show that the marginal profits and mark-ups of firms are greater in both core and peripheral regions than in between, due to a subtle interplay between competition and market-access forces. Production is mostly monocentric, however, and profits are higher in the core, which should produce further concentration. We finally show that policy-makers face a difficult trade-off: lowering inter-regional trade costs reduces disparities between regions, but increases intra-regional inequality.