Robust Deviations from Signaling Equilibria

In Sender-Receiver games with costly signaling, some equilibria are vulnerable to deviations which could be "unambiguously" interpreted by the Receiver as coming from a unique set of possible Sender-types. The vulnerability occurs when the types in this set are the ones who gain from the deviation, regardless of the posterior beliefs the Receiver forms over that set. We formalize this idea and use it to characterize a unique equilibrium outcome in two classes of games. First, in mono- tonic signaling games, only the Riley outcome is immune to this sort of deviation. Our result therefore provides a plausible story behind the selection made by Cho and Kreps' (1987) D1 criterion on this class of games. Second, we examine a version of Crawford and Sobel's (1982) model but with costly signaling and finite type sets, where standard refinements have no effect. We show that only a Riley-like separating equilibrium is immune to these deviations.Signaling games, Sender-Receiver, robust equilibrium, re¯nements.

Ten Little Treasures of Game Theory and Ten Intuitive Contradictions

This paper reports laboratory data for a series of two-person games that are played only once. These games span the standard categories: static and dynamic games with complete and incomplete information. For each game, the treasure is a treatment for which behavior conforms quite nicely to the predictions of the Nash equilibrium or relevant refinement. In each case we change a key payoff parameter in a manner that does not alter the equilibrium predictions, but this theoretically neutral payoff change has a major (often dramatic) effect on observed behavior. These contradictions are generally consistent with simple economic intuition and with a model of iterated noisy introspection for one-shot games.Nash equilibrium, noncooperative games, experiments, bounded rationality, introspection

Signaling and forward induction in a market entry context

Game Theory;Market Structure

Overreporting Oil Reserves

An increasing number of oil market experts argue that OPEC members substantially overstate their oil reserves. While the economic implications could be dire, the incentives for overreporting remain unclear. This paper analyzes these incentives, showing that oil exporters may overreport to raise expected future supply, thereby discouraging oil-substituting R&D and improving their own future market conditions. In general, however, overreporting is not costless: it must be backed by observable actions and therefore induces losses through supply distortions. Surprisingly, these distortions offset others that arise when suppliers internalize the buyers' motives for R&D. In this case, overreporting is rational, credible, and cheap.Exhaustible Resource, Substitution Technology, Signaling

Selecting a pooling equilibrium in a signaling game with a bounded set of signals

In this paper, we study a general class of monotone signaling games, in which the support of the signal is limited or the cost of the signal is sufficiently low and as a result, there are multiple pooling equilibria. In those games, when we relax the usual single-crossing condition, the typical restrictions on the out-of-equilibrium beliefs suggested by previous literature cannot discard any of the equilibria obtained. For this reason, we develop a new refinement called the most profitable deviator, which will be useful to select a unique equilibrium in those games. Additionally, when the standard single-crossing condition is satisfied, our criterion also chooses a unique equilibrium, which is the same as that selected by previous literature.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Credible ratings

This paper considers a model of a rating agency with multiple clients, in which each client has a separate market that forms a belief about the quality of the client after the agency issues a rating. When the clients are rated separately (individual rating), the credibility of a good rating in an inflationary equilibrium of the signaling game is limited by the incentive of the agency to exaggerate the quality of the client. In centralized rating, the agency rates all clients together and shares the rating information among all markets. This allows the agency to coordinate the ratings and achieve a higher average level of credibility for its good ratings than in individual rating. In decentralized rating, the ratings are again shared among all markets, but each client is rated by a self-interested rater of the agency with no access to the quality information of other clients. When the underlying qualities of the clients are correlated, decentralized rating leads to a smaller degree of rating inflation and hence a greater level of credibility than in individual rating. Comparing centralized rating with decentralized rating, we find that centralized rating dominates decentralized rating for the agency when the underlying qualities are weakly correlated, but the reverse holds when the qualities are strongly correlated.Signaling, credibility, individual rating, centralized rating, decentralized rating

Signaling Fiscal Regime Sustainability

This paper proposes a signaling model of fiscal stabilizations that offers a new perspective on why governments deviate from optimal tax smoothing. In our model, dependable - but not fully credible - governments have an incentive to tighten the fiscal regime when the signaling effect on credit ratings is larger (that is, when a sufficiently large stock of debt has been accumulated). At this point, they may deviate from tax smoothing in order to avoid being mimicked by weak governments. We show that a testable prediction of our model is that primary balances and debt stocks are complementary inputs in the credit rating function and we successfully test it on Irish, Belgian, and Danish data from the late 1970s to the early 1990s.fiscal policy, taxation, debt, credit, economic models

Competition, Reputation and Cheating

Under repeated market interaction, reputation and competition may drive out of the market those firms that do not comply with their quality promises. One may thus presume that competitive pressure improves average market quality. This paper shows that the opposite may be true in an endogenous entry, repeated interaction, linear demand oligopoly model, in which introductory prices may be used as quality signals. Cheating firms may enter the market, fool even rational consumers, and exit the market when discovered, implying a failure of the basic reputation mechanism and an increasing time path of prices. Markets for closer substitutes tend to have a lower initial average quality and less trusting consumers, whereas the number of competitors has no clear relationship with average quality.