Optimal Patent Protection in a Two-Sector Economy

This article addresses the issue of optimal patent protection in an economy with a downstream and an upstream sector. The key insight is that higher patent protection in the downstream sector raises the incentives of agents to do R&D in that sector but discourages innovation in the upstream sector because of a market size effect. Hence, higher patent protection in the upstream sector accelerates growth whereas higher patent protection in the downstream sector slows it down. If some innovation is socially desirable, optimal patent protection is necessarily higher in the upstream than in the downstream sector.     

CDM 20 years after

ABSTRACT

In year 1998, the seminal paper Research Innovation and Productivity: An Econometric Analysis at the Firm Level was published in this journal. The empirical framework, following on ideas in the research of Zvi Griliches at the NBER and commonly labeled CDM (the acronym of the three authors’ names, Crépon, Duguet and Mairesse) is one of the most influential contributions in recent literature on economics of innovation. The original CDM paper and papers inspired by its framework have received hundreds of citations in the empirical innovation literature. Whether directly linked or not to the CDM framework, the flow of studies improving on and enlarging the scope and methods of the empirical literature on R&D, innovation and productivity is continuing. Some of them, for example, focus on financing innovation, innovation and employment, innovation and trade, competition, or intellectual property; some adopt a managerial perspective, while others prefer an innovation system approach in a Schumpeterian tradition, etc. This introduction to the special issue of EINT surveys a collection of 12 papers on the CDM model by 25 authors from eight countries. The papers take stock of the evolution of research based on the original CDM model launched 20 years ago, linking it to the previous literature, and proposing developments and generalizations of it in various dimensions.     

On the impact of leverage constraints on asset prices and trading volume

Abstract. Researchers have used stylized facts on asset prices and trading volume in stock markets (in particular, the mean reversion of asset returns and the correlations between trading volume, price changes and price levels) to support theories where agents are not rational expected utility maximizers. This paper shows that this empirical evidence is in fact consistent with a standard infinite horizon – perfect information – expected utility economy where some agents face leverage constraints similar to those found in todays financial markets. In addition, and in sharp contrast to the theories above, we explain some qualitative differences that are observed in the price-volume relation on stock and on futures markets. We consider a continuous-time economy where agents maximize the integral of their discounted utility from consumption under both budget and leverage constraints. Building on the work by Vila and Zariphopoulou (1997), we find a closed form solution, up to a negative constant, for the equilibrium prices and demands in the region of the state space where the constraint is non-binding. We show that, at the equilibrium, stock holdings volatility as well as its ratio to stock price volatility are increasing functions of the stock price and interpret this finding in terms of the price-volume relation. We would like to thank the editor and two anonimous referees for valuable substantive comments. Our gratitude also to Franklin Allen, Kerry Back, Domenico Cuoco, Xavier Freixas, Sanford Grossman, Michel Habib, Lutz Hendricks, Richard Kihlstrom, Fernando Restoy, Mary Thomson, Jean-Luc Vila, participants to seminars at Birkbeck College, Carnegie-Mellon, Columbia, ESSEC, HEC, IAE, INSEAD, London Business School, London School of Economics, McGill, Michigan, National University of Singapore, Pompeu Fabra, North Carolina, Washington-St-Louis, Wharton, the Jornadas de Economía Financiera BBV, and the Meetings of the Society for Economic Dynamics and Control and the American Finance Association. Special thanks are due to Süleyman Basak for his enthusiastic support and many helpful suggestions. The usual disclaimer applies. We gratefully acknowledge the support of the BBV and Caja de Madrid Foundations and CREF (both authors) and of the Spanish Ministry of Education under DGICYT grant no. PB93-0388 (first author).     

Production and financial policies under asymmetric information

We propose an extension of the standard general equilibrium model with production and incomplete markets to situations in which (i) private investors have limited information on the returns of specific assets, (ii) managers of firms have limited information on the preferences of individual shareholders. The extension is obtained by the assumption that firms are not traded directly but grouped into ‘sectorial’ funds. In our model the financial policy of the firm is not irrelevant. We establish the existence of equilibria and discuss the nature of the inefficiencies introduced by the presence of asymmetric information. We also illustrate the properties of the model in three simple examples. We would like to thank Alberto Bisin, Armando Dominioni, Piero Gottardi, Tito Pietra, Paolo Siconolfi, and an anonymous referee for useful suggestions and comments.     

Transportation in disaster response operations

Disasters are extraordinary situations that require significant logistical deployment to transport equipment and humanitarian goods in order to help and provide relief to victims. An efficient response helps to reduce the social, economic and environmental impacts. In this paper, we define and formulate a practical transportation problem often encountered by crisis managers in emergency situations. Since optimal solutions to such a formulation may be achieved only for very small-size instances, we developed an efficient genetic algorithm to deal with realistic situations. This algorithm produces near optimal solutions in relatively short computation times and is fast enough to be used interactively in a decision-support system, providing high-quality transportation plans to emergency managers.     

Relative deprivation,reference groups and the assessment of standard of living

This paper proposes two new indices of relative deprivation, derived from an extension of the concept of generalized Gini to the measurement of distributional change. Population- and income-weighted relative deprivation indices are then defined and, using panel data from the Consortium of Household Panels for European Socio-Economic Research (CHER), we check which of the various ways of defining individual deprivation best fits the answers given by individuals on the degree of their satisfaction with income. We find that the deprivation indices proposed are consistently and negatively correlated with income satisfaction as reported by respondents, that income weighted measures fit better than population weighted measures and that this fit improves with countries that experienced deep institutional changes such as the transitional economies of Eastern Europe.     

WHICH AGGLOMERATION EXTERNALITIES MATTER MOST AND WHY?

This paper revisits the ongoing discussion on the importance of agglomeration externalities – specifically specialization, diversity and competition effects – that may contribute to innovation, productivity and urban employment growth. Previous meta‐analyses suggested that the evidence on agglomeration externalities is strongly context‐specific. Expanding an earlier analysis of 31 articles, we seek to draw in this paper more robust conclusions by means of the statistical evidence for agglomeration externalities presented in 73 scientific articles, all building on the seminal work of Glaeser et al. (1992). Our results confirm that the heterogeneity among studies is huge and can only be partially accounted for by means of an ordered probit analysis. Additionally, some evidence of publication bias is found. We conclude that the conventional lines of inquiry in this literature may now have reached strongly diminishing returns. New lines of inquiry, using rich micro‐level data on firms and workers, dynamic general equilibrium models at the macro level, more attention for spatial and temporal variation in the impacts of agglomeration, and further investigations into the spatial scope of externalities are promising avenues for further research that can enhance our understanding of how agglomeration externalities continue to fuel our increasingly urbanized world.     

On supply-constrained equilibria

The paper gives sufficient conditions for the existence of an equilibrium with price rigidities and quantity rationing where: (i) demand is never rationed; (ii) net trades of an a priori chosen numeraire are never rationed; and (iii) supply is rationed only when relative prices are downward rigid.     

Optimal search auctions

We study the design of profit maximizing single unit auctions under the assumption that the seller needs to incur costs to contact prospective bidders and inform them about the auction. With independent bidders’ types and possibly interdependent valuations, the seller's problem can be reduced to a search problem in which the surplus is measured in terms of virtual utilities minus search costs. Compared to the socially efficient mechanism, the optimal mechanism features fewer participants, longer search conditional on the same set of participants, and inefficient sequence of entry.