Robustness to Strategic Uncertainty (Revision of DP 2010-70)

We model a player’s uncertainty about other players’ strategy choices as smooth probability distributions over their strategy sets. We call a strategy profile (strictly) robust to strategic uncertainty if it is the limit, as uncertainty vanishes, of some sequence (all sequences) of strategy profiles, in each of which every player’s strategy is optimal under under his or her uncertainty about the others. We derive general properties of such robustness, and apply the definition to Bertrand competition games and the Nash demand game, games that admit infinitely many Nash equilibria. We show that our robustness criterion selects a unique Nash equilibrium in the Bertrand games, and that this agrees with recent experimental findings. For the Nash demand game, we show that the less uncertain party obtains the bigger share.Nash equilibrium;refinement;strategic uncertainty;price competition;Bertrand competition;bargaining;Nash demand game

Robustness to Strategic Uncertainty (Revision of DP 2010-70)

We model a player’s uncertainty about other players’ strategy choices as smooth probability distributions over their strategy sets. We call a strategy profile (strictly) robust to strategic uncertainty if it is the limit, as uncertainty vanishes, of some sequence (all sequences) of strategy profiles, in each of which every player’s strategy is optimal under under his or her uncertainty about the others. We derive general properties of such robustness, and apply the definition to Bertrand competition games and the Nash demand game, games that admit infinitely many Nash equilibria. We show that our robustness criterion selects a unique Nash equilibrium in the Bertrand games, and that this agrees with recent experimental findings. For the Nash demand game, we show that the less uncertain party obtains the bigger share.

Robustness to strategic uncertainty in price competition

We model a player's uncertainty about other player's strategy choices as probability distributions over their strategy sets. We call a strategy profile robust to strategic uncertainty if it is the limit, as uncertainty vanishes, of some sequence of strategy profiles in each of which every player's strategy is optimal under his or her uncertainty about the pthers. We apply this definition to Bertrand games with a continuum of equilibrium prices and show that our robustness criterion selects a unique Nash equilibrium price. This selection agrees with available experimental findings.Nash equilibrium; refinement; strategic uncertainty; price competition

Robust Predictions in Games with Incomplete Information

We analyze games of incomplete information and offer equilibrium predictions which are valid for all possible private information structures that the agents may have. Our characterization of these robust predictions relies on an epistemic result which establishes a relationship between the set of Bayes Nash equilibria and the set of Bayes correlated equilibria. We completely characterize the set of Bayes correlated equilibria in a class of games with quadratic payoffs and normally distributed uncertainty in terms of restrictions on the first and second moments of the equilibrium action-state distribution. We derive exact bounds on how prior information of the analyst refines the set of equilibrium distribution. As an application, we obtain new results regarding the optimal information sharing policy of firms under demand uncertainty. Finally, we reverse the perspective and investigate the identification problem under concerns for robustness to private information. We show how the presence of private information leads to partial rather than complete identification of the structural parameters of the game. As a prominent example we analyze the canonical problem of demand and supply identification.Incomplete information, Correlated equilibrium, Robustness to private information, Moments restrictions, Identification, Information bounds

An "informationally robust equilibrium" for two-person nonzero-sum games

Game Theory;Equilibrium Theory

Industrial organization and the economics of business strategy.

Industrial organization (IO) has an important role to play in inspiring the competition and regulation policies of the government. At the same it can be used to clarify the economics of business strategies. The idea here is not to give a comprehensive review, but to draw attention to some striking tendencies, prospects and problems of the field of IO as a source of inspiration for competitive strategies. A first focus will be on credible market strategies and asymmetric information, with implications for internal organization, vertical foreclosure and markets with switching costs. A second point will look at detection of not so obvious possibilities, as there are lower prices with cooperation, disadvantageous mergers, positive side effects for rivals, and disadvantageous price discrimination. Finally some approaches will be discussed to problems concerning high requirements on rationality and lack of robustness. An example will be discussed of a search for robustness in strategic investment models in oligopoly settings with leaders and followers.Economics; Strategy;

Bureaucratic institutional design. The case of the Italian NHS

We propose a model where a regional government’s choice of the number of bureaucratic agencies operating in a region depends upon the degree of substitutability and complementarity of the bureaucratic services being demanded. We show that, if the government perceives the citizens’ demand as a demand for substitutable services, it will choose provision by two independent agencies. If the government perceives the citizens’ demand as a demand for complementary services, it will choose provision by a single consolidated agency. Exogenous shocks to the number of citizens amplify these incentives. Evidence from the Italian National Health Service (NHS) supports this hypothesis. Results show a positive effect of proxies of substitutable services on the number of regional Local Health Authorities (LHAs) and a negative effect of proxies of complementary services. The major immigration amnesties, taken as shocks to the number of citizens entitled to the service, magnify these effects