Dynamic R&D competition with memory

We consider a differential game of R&D competition and explore the impact of rivalry on the firms' investment behavior over time. Using closed-loop strategies and hence allowing for strategic interactions among rival firms we show that R&D spending by the individual competitor is increased due to competition in the race for priority. This leads us to argue that competitive encounters enhance R&D activities at the same time as increasing efficiency in the race for a technological breakthrough.     

A child health production function estimated from longitudinal data. Cebu Study Team

Collaborating researchers used a multi equation model to analyze 3080 mother-infant pairs living on the island of Cebu in the central Philippines and to estimate a child health production function. The econometric methods used eliminated obstacles such as heterogeneity and endogeneity of significant explanatory factors. They also maximized the longitudinal quality of the data. The results showed that morbidity in 1 period reduced infant weight in following periods. For example, diarrhea and febrile respiratory infection reduced growth in the time period following the illnesses. Further effects of some contributing factors were great near birth not diminished with age. For example, breast feeding promoted growth and protected against infection, especially diarrhea and febrile respiratory infection, more substantially near birth than it did later. Further, in urban areas, preventive health care positively affected growth independently of its indirect influence on reducing respiratory infection. Yet it had little effect on diarrhea. Diarrhea had a strong adverse effect on growth. Exposure of the infant to enteric pathogens had the greatest influence on production of diarrhea. In urban areas, exposure included water supply contamination, exposure to feces, a more pathogenic diet, and community crowding. In rural areas, however, exposure included community crowding and increased rainfall which presumably washed feces into the water supply. Household crowding in both urban and rural areas and irritation from smoke in urban areas only tended to bring about febrile respiratory infection.     

The Nonparametric Approach to Applied Welfare Analysis

Changes in total surplus are traditional measures of economic welfare. We propose necessary and sufficient conditions for rationalizing individual and aggregate consumer demand data with individual quasilinear and homothetic utility functions. Under these conditions, consumer surplus is a valid measure of consumer welfare. For nonmarketed goods, we propose necessary and sufficient conditions on input market data for efficient production, i.e. production at minimum cost. Under these conditions we derive a cost function for the nonmarketed good, where producer surplus is the area above the marginal cost curve. We are greatful to helpful remarks and comments of the referees and the editor. The work is partially supported by the Spanish Ministry of Science and Technology, through Grant BEC2002-2130, the Generalitat de Catlaunya, through Grant 2005SGR-00454 and the Barcelona Economics Program (CREA).     

Rock Paper Scissors

Rock Paper Scissors is used to resolve conflict when a compromise is not possible. Individuals playing ``games' tend to have biases they prefer to play. I show that Rock Paper Scissors with biased players results in a player with a high valuation for winning being victorious with a probability greater than a player with a low valuation. Thus, it frequently achieves the efficient outcome. Furthermore, as the benefit to victory increases for all players, victory for each player becomes equally likely. Therefore, it is often efficient for minor conflicts while it performs no better than a coin-flip for major conflicts.      

Competition with Congestible Networks

We analyse competition between two network providers when the quality of each network depends negatively on the number of customers connected to that network. With respect to price competition we provide a sufficient condition for the existence of a unique pure strategy Nash equilibrium. Comparative statics show that as the congestion effect gets stronger quantities will decrease and prices increase, under both Bertrand and Cournot competition. In an example with endogenous capacities it turns out that equilibrium capacities are at first increasing and then decreasing in the strength of congestion. Furthermore, capacities are higher under Cournot competition. Welfare comparisons between Bertrand and Cournot competition are unambiguous for fixed capacities, but may turn around for endogenous capacities.     

Pricing access in network competition

We compare various access pricing rules in the two-way access model. We show that the Generalized Efficient Component Pricing Rule (TECPR) leads to a lower equilibrium price than does the Efficient Component Pricing Rule, (ECPR) marginal cost pricing, (MCP) and any non-negative fixed access charges.