We study games with strategic complementarities, arbitrary numbers of players and actions, and slightly noisy payoff signals. We prove limit uniqueness: as the signal noise vanishes, the game has a unique strategy profile that survives iterative dominance. This generalizes a result of Carlsson and van Damme (1993) for two player, two action games. The surviving profile, however, may depend on fine details of the structure of the noise. We provide sufficient conditions on payoffs for there to be noise-independent selection.
We study games with strategic complementarities, arbitrary numbers of players and actions, and slightly noisy payoff signals. We prove limit uniqueness: as the signal noise vanishes, the game has a unique strategy profile that survives iterative dominance. This generalizes a result of Carlsson and van Damme (1993) for two player, two action games. The surviving profile, however, may depend on fine details of the structure of the noise. We provide sufficient conditions on payoffs for there to be noise-independent selection.
JEL Classification: C72, D82
Keywords: Equilibrium selection, global games, strategic complementarities, supermodular games
What are the welfare effects of enhanced dissemination of public information through the media and disclosures by market participants with high public visibility? For instance, is it always desirable to have frequent and timely publications of economic statistics by government agencies and the central bank? We examine the impact of public information in a setting where agents take actions appropriate to the underlying fundamentals, but they also have a coordination motive arising from a strategic complementarity in their actions. When the agents have no private information, greater provision of public information always increases welfare. However, when agents also have access to independent sources of information, the welfare effect of increased public disclosures is ambiguous.
Global games are games of incomplete information whose type space is determined by the players each observing a noisy signal of the underlying state. With strategic complementarities, global games often have a unique, dominance solvable equilibrium, allowing analysis of a number of economic models of coordination failure. For symmetric binary action global games, equilibrium strategies in the limit (as noise becomes negligible) are simple to characterize in terms of ‘diffuse’ beliefs over the actions of others. We describe a number of economic applications that fall in this category. We also explore the distinctive roles of public and private information in this setting, review results for general global games, discuss the relationship between global games and a literature on higher order beliefs in game theory and describe the relationship to local interaction games and dynamic games with payoff shocks.
Global games are games of incomplete information whose type space is determined by the players each observing a noisy signal of the underlying state. With strategic complementarities, global games often have a unique, dominance solvable equilibrium, allowing analysis of a number of economic models of coordination failure. For symmetric binary action global games, equilibrium strategies in the limit (as noise becomes negligible) are simple to characterize in terms of ‘diffuse’ beliefs over the actions of others. We describe a number of economic applications that fall in this category. We also explore the distinctive roles of public and private information in this setting, review results for general global games, discuss the relationship between global games and a literature on higher order beliefs in game theory and describe the relationship to local interaction and dynamic games with payoff shocks.
Global games are games of incomplete information whose type space is determined by the players each observing a noisy signal of the underlying state. With strategic complementarities, global games often have a unique, dominance solvable equilibrium, allowing analysis of a number of economic models of coordination failure. For symmetric binary action global games, equilibrium strategies in the limit (as noise becomes negligible) are simple to characterize in terms of ‘diffuse’ beliefs over the actions of others. We describe a number of economic applications that fall in this category. We also explore the distinctive roles of public and private information in this setting, review results for general global games, discuss the relationship between global games and a literature on higher order beliefs in game theory and describe the relationship to local interaction and dynamic games with payoff shocks.
Keywords: Global games, common knowledge, unique equilibrium, currency crises, bank runs and liquidity
Do large investors increase the vulnerability of a country to speculative attacks in the foreign exchange markets? To address this issue, we build a model of currency crises where a single large investor and a continuum of small investors independently decide whether to attack a currency based on their private information about fundamentals. Even abstracting from signalling, the presence of the large investor does make all other traders more aggressive in their selling. Relative to the case in which there is no large investors, small investors attack the currency when fundamentals are stronger. Yet, the difference can be small, or null, depending on the relative precision of private information of the small and large investors. Adding signalling makes the influence of the large trader on small traders’ behaviour much stronger.
The electronic mail game of Rubinstein (1989) showed that a lack of common knowledge generated by faulty communication can make coordinated action impossible. This paper shows how this conclusion is robust to having a more realistic timing structure of messages, more than two players who meet publicly but not as a plenary group, and strategic decisions about whether to communicate.
The electronic mail game of Rubinstein (1989) showed that a lack of common knowledge generated by faulty communication can make coordinated action impossible. This paper shows how this conclusion is robust to having a more realistic timing structure of messages, more than two players who meet publicly but not as a plenary group, and strategic decisions about whether to communicate.
The electronic mail game of Rubinstein (1989) showed that a lack of common knowledge generated by faulty communication can make coordinated action impossible. This paper shows how this conclusion is robust to having a more realistic timing structure of messages, more than two players who meet publicly but not as a plenary group, and strategic decisions about whether to communicate.
Keywords: Electronic mail, common knowledge, coordination
Are beliefs as indeterminate as auggested by models with multiple equilibria? Multiplicity of equilibria arise largely as the unintended consequence of two modelling assumptions — the fundamentals are assumed to be common knowledge, and economic agents know others’ actions in equilibrium. Both are questionable. When others’ actions are not known with certainty, such as when actions rely on noisy signals, self-fulfilling beliefs lead to a unique outcome determined by the fundamentals and the knowledges that others are rational. This paper illustrates this approach in the context of a model of bank runs and other similar applications. Such an approach places comparative statics and policy analyses on a firmer footing. It also suggests that public information has a disproportionately larger impact on the outcome than private information.
Are beliefs as indeterminate as auggested by models with multiple equilibria? Multiplicity of equilibria arise largely as the unintended consequence of two modelling assumptions — the fundamentals are assumed to be common knowledge, and economic agents know others’ actions in equilibrium. Both are questionable. When others’ actions are not known with certainty, such as when actions rely on noisy signals, self-fulfilling beliefs lead to a unique outcome determined by the fundamentals and the knowledges that others are rational. This paper illustrates this approach in the context of a model of bank runs and other similar applications. Such an approach places comparative statics and policy analyses on a firmer footing. It also suggests that public information has a disproportionately larger impact on the outcome than private information.
Keywords: Multiple equilibria, macroeconomics, common knowledge