Subject pool effects in price competition games: students versus professionals

Questioning the external validity of experiments that rely on student participants is an evergreen theme in experimental economics. Yet, there is ambiguous evidence of potential subject-pool bias. We add to the subject-pool debate by enlarging the set of experiments for which subject-pool differences have been studied. In a duopolistic Bertrand market setup designed to test for collusive behaviour, we test two treatments. The first is a baseline treatment, where participants cannot communicate with each other, while the second is a communication treatment in which participants are allowed to communicate. Each treatment is first conducted with students and then replicated with professionals. Our results show that student subjects and professionals differ significantly. However, these differences manifest themselves in quantitative rather than qualitative terms. Professionals do collude more, but their behavioural difference between treatments is similar. Students are thus a valid surrogate, if the research question is qualitative, but results generated by student samples should be handled with caution, if quantitative differences matter.     

Inflow Uncertainty in Hydropower Markets

We analyse the effects of uncertainty on market performance in hydropower systems under alternative assumptions about market structure. Uncertainty creates distinct possibilities for exercising market power that cannot be captured in deterministic models. The qualitative and quantitative features of these possibilities depend on the characteristics of residual demand facing individual firms, which again depends on consumer preferences and generation and transmission technologies.     

Market share dynamics in a duopoly model with word-of-mouth communication

We analyze dynamic price competition in a homogeneous goods duopoly, where consumers exchange information via word-of-mouth communication. A fraction of consumers, who do not learn any new information, remain locked-in at their previous supplier in each period. We analyze Markov perfect equilibria in which firms use mixed pricing strategies. Market share dynamics are driven by the endogenous price dispersion. Depending on the parameters, we obtain different ‘classes’ of dynamics. When firms are impatient, there is a tendency towards equal market shares. When firms are patient, there are extended intervals of market dominance, interrupted by sudden changes in the leadership position.     

横向兼并的均衡影响分析——基于供给函数竞争的兼并模型

对于横向兼并所产生的影响,现有研究成果多是在产量竞争的古诺模型或基于价格竞争的伯川德模型基础上进行的.本文以Ugue(2004)提出的供给函数竞争概念为基础,考察了横向兼并、产业集中与福利权衡的关系,分析在同质产品市场上,供给函数竞争对企业横向兼并产生的均衡影响,并与古诺模型做了对比分析.基本结论为:供给函数竞争下,任何兼并都会使产业的总产出下降,价格升高.供给函数竞争导致产量的下降,不仅仅由于兼并企业减少产量,而且非兼并企业也会减少供给,结果导致兼并总是有利可图.     

Bertrand Price Undercutting: A Brief Classroom Demonstration

The author presents a brief classroom demonstration illustrating Bertrand price undercutting. The demonstration is appropriate for micro principles and intermediate- and upper-level undergraduate classes, as well as graduate classes in micro, industrial organization, and game theory.     

Market Power,Industrial Organization and Tradeable Quotas

Individual Transferable Quotas (ITQs) wereintroduced into the Mid-Atlantic Surf Clam and OceanQuahog fishery to reduce over-capitalization whileconserving clam populations. Because the number ofoperators in the fishery declined drastically sincethe introduction of this policy, there is concernabout its effect on competitiveness. This paperutilizes Bertrand Pricing Models to show thatmonopoly power is absent from the surf clam andocean quahog markets. Concentration ratios, Lorenzcurves and Gini Coefficients estimated for thefishery for periods before and after ITQintroduction support the results of the Bertrand model.     

Existence of Bertrand equilibrium revisited

In this paper we reconsider existence of Bertrand equilibrium in a symmetric‐cost, homogenous‐product oligopoly. We prove the following main results. (a) If the cost function is strictly superadditive on [0, ∞) then there exists a pure strategy Bertrand equilibrium. Such Bertrand equilibria are necessarily non‐unique. (b) If the cost function is strictly subadditive on [0, ∞) then there exists no Bertrand equilibrium, either in pure strategies or in mixed strategies.     

Learning in asymmetric duopoly markets: competition in information and market correlation

This paper explores experimentation and learning in asymmetric duopoly markets with product differentiation and demand uncertainty. We define the concepts of strategic substitutability and strategic complementarity in information and we show how both the mode of information competition and the transmission of information across markets affect duopoly experimentation. We relate information competition with market competition and we find that, when goods are substitutes and the correlation between market shocks is negative, firms will have a higher incentive to experiment in asymmetric markets than in symmetric ones. The opposite result follows when such correlation is positive. Also, when goods are complements the above findings are reversed.JEL Classification: D83, C72The authors thank partial financial support from the Spanish Ministry of Science and Technology under project B2000-1429, from the Spanish Ministry of Education and Science under project SEJ2004-07554 and from the “Generalitat Valénciana” under project GRUPOS04/13.     

寡头垄断、非线性定价与非对称价格规制

本文系统研究了非对称寡头垄断行业的价格规制问题。在非对称双寡头垄断市场结构的假设下,本文首先分析了双寡头企业的非线性定价行为与市场均衡。双寡头企业都基于各自边际成本的最优非线性价格,以及实现福利最大化的价格和竞争性均衡价格,其价格套餐都会发生交叉,进而产生市场分割。以此为理论基础,在综合考虑价格规制目标、可实施条件和行业现状的基础上,本文给出了非对称双寡头垄断行业价格规制的总体思路设计：在垄断行业引入竞争机制改革的过渡时期,应采取非对称价格规制,双寡头企业的规制价格套餐交叉导致的市场分割,会有利于有效竞争的市场格局最终形成。     

The value of commitment in Stackelberg games with observation costs

We study Stackelberg games in which the follower faces a cost for observing the leader's action. We show that, irrespective of the size of the cost, the leader's value of commitment is lost completely in all pure-strategy equilibria. However, there also exists a mixed-strategy equilibrium that fully preserves the first-mover advantage. In this type of equilibrium, the probability that the follower looks at the leader's action is independent of the cost of looking.