Financing the New Economy : its Impact on Growth.

L’exceptionnelle performance de l’économie des Etats-Unis durant les années 1990 a conduit les économistes à s’interroger successivement sur le phénomène de la nouvelle économie, la réalité de ses effets favorables et les risques qu’elle engendre. Au cœur de ces trois interrogations, se situe celle du rôle que pourrait jouer en positif et en négatif les conditions nouvelles de financement de la croissance et singulièrement celles de la nouvelle économie. Dans une première partie, nous reviendrons sur la définition des termes. Les termes utilisés recouvrent en effet des concepts loin d’être identiques pour tous. Cet exercice de clarification nous permettra, en outre, d’identifier certaines interactions existant entre les différents éléments, et surtout de mettre en évidence l’existence d’un mode de financement spécifique à la nouvelle économie. Dans une seconde partie, nous tenterons de cerner les éléments de réponses apportés par la théorie de la croissance économique sur la manière dont le financement de la nouvelle économie peut influer sur la croissance. En particulier, la productivité étant identifiée comme la principale source de la croissance, nous nous interrogerons sur le fait de savoir si le financement de la nouvelle économie permet d’obtenir des gains de productivité et si ces gains peuvent justifier le niveau de valorisation des actifs de ce secteur. Cependant, la question de la justification des conditions de rentabilisation propre au secteur de la nouvelle économie nécessite de quantifier le risque pesant sur la nouvelle économie. C’est pourquoi nous présenterons, dans une troisième partie, les analyses divergentes d’économistes, avant de présenter nos propres conclusions et mettrons en évidence la réalité d’un risque financier mais aussi d’un risque économique.Croissance; Nouvelle économie;

Comparing TFP Catching-up and Capital Deepening in US and European Growths: A Directional Distance Function Approach

In Solow’s model the income convergence between countries arises from two main sources: a capital deepening effect resulting from the diminishing returns of the production technology and a technological transfer/diffusion effect related to Total Factor Productivity (TFP) differences. A large literature has been devoted to analyze these effects but most of the studies suffer from three weaknesses by defining the US as the a priori technological leader, by using a parametric functional form and by assuming constant returns to scale for the technology. Our paper offers an alternative approach based on a non-parametric programming framework and the estimation of directional distance functions. We explicitly separate country TFP differences into two components: a technology effect and a scale effect to study the catching-up process on each of them. We also analyze the role of the capital deepening effect by introducing a relevant measure of the structural efficiency which reveals inefficiencies due to changes in input-ratio differences. Our empirical work focuses on 15 European countries (EU) and the US over the period 1980-2004. We use time series procedures to test for convergence for individual countries or sub-sets of countries.TFP Catching-up, Capital Deepening, Convergence, Directional Distance Function. Running title: Comparing TFP Catching-up and Capital Deepening

A fast and recursive algorithm for clustering large datasets with kk-medians

Clustering with fast algorithms large samples of high dimensional data is an important challenge in computational statistics. Borrowing ideas from MacQueen (1967) who introduced a sequential version of the $k$-means algorithm, a new class of recursive stochastic gradient algorithms designed for the $k$-medians loss criterion is proposed. By their recursive nature, these algorithms are very fast and are well adapted to deal with large samples of data that are allowed to arrive sequentially. It is proved that the stochastic gradient algorithm converges almost surely to the set of stationary points of the underlying loss criterion. A particular attention is paid to the averaged versions, which are known to have better performances, and a data-driven procedure that allows automatic selection of the value of the descent step is proposed. The performance of the averaged sequential estimator is compared on a simulation study, both in terms of computation speed and accuracy of the estimations, with more classical partitioning techniques such as $k$-means, trimmed $k$-means and PAM (partitioning around medoids). Finally, this new online clustering technique is illustrated on determining television audience profiles with a sample of more than 5000 individual television audiences measured every minute over a period of 24 hours.Comment: Under revision for Computational Statistics and Data Analysi

An economic history of the Champagne contracts, lessons for regional development

This paper highlights the success factors of the governance of the Champagne supply chain. Scholars on economic organisation stress the role of the contractual enforcement to explain the stability of the economic exchanges and the ability of the economic and political actors to foster their own development (NORTH 1999). Our contribution detailed explicit and implicit mechanisms related to the vinegrower-merchant relations in the regional system. The Champagne region had the particularity to posses a double-head organisation, regrouping all the farms and firms involved in the agronomic, and commercial process of the regional wines. This private board is supported by an institutional environment, common market organisation, French rural acts, and national and international legislations on geographical indication. These legislatives and administrative components define precisely the productive and market rules. Rely on a longitudinal approach we reinterpret the way the interprofessionnal (general) agreement, essential part of the governance of the regional market, evolved during decades (BARRERE 2003). This rereading illustrates the interdependency between explicit and implicit enforcement mechanisms which foster the cooperation. We argue that asymmetric investments in advertising play a major role in the stability of the regional cooperation. The achievement of the reputation of the AOC Champagne by massive advertising and commercial investments mainly realised by the negociants is central to understand the convergence of both party strategies on a long term. These investments step in as catalyst of a negotiated environment and award the self-enforcing character of the contracts. It makes efficient the set of private arrangements and regulatory mechanisms designed to eradicate opportunistic behaviours. During all the second part of the 20th century, the form of the contractual agreements evolved. Governance tools were added and suppressed. However these forced or desired adaptations slightly alter the nature of the cooperative process. The flexibility of the private arrangement, as well as the comprehensive economic policy, ensures the durability of the general agreement in spite of crisis. These results backup the hypothesis of the new institutional economics on the necessity of complementary institutions to make the market efficient (AOKI 2001).