Essays on dynamic games and reputations

Abstract

This thesis consists of three essays on dynamic games with incomplete information. In Chapter 1, I study reputation effects when individuals have persistent private information that matters for their opponents' payoffs. I examine a repeated game between a patient informed player and a sequence of myopic uninformed players. The informed player privately observes a persistent state, and is either a strategic type who can flexibly choose his actions or is one of the several commitment types that mechanically plays the same action in every period. Unlike the canonical models on reputation effects, the uninformed players' payoffs depend on the state. This interdependence of values introduces new challenges to reputation building, namely, the informed player could face a tradeo between establishing a reputation for commitment and signaling favorable information about the state. My results address the predictions on the informed player's payoff and behavior that apply across all Nash equilibria. When the stage game payoffs satisfy a monotone-supermodularity condition, I show that the informed long-run player can overcome the lack-of-commitment problem and secure a high payoff in every state and in every equilibrium. Under a condition on the distribution over states, he will play the same action in every period and maintain his reputation for commitment in every equilibrium. If the payoff structure is unrestricted and the probability of commitment types is small, then the informed player's return to reputation building can be low and can provide a strict incentive to abandon his reputation. In Chapter 2, I study the dynamics of an agent's reputation for competence when the labor market's information about his performance is disclosed by an intermediary who cannot commit. I show that this game admits a unique Markov Perfect Equilibrium (MPE). When the agent is patient, his effort is inverse U-shaped, while the rate of information disclosure is decreasing over time. I illustrate the inefficiencies of the unique MPE by comparing it with the equilibrium in the benchmark scenario where the market automatically observes all breakthroughs. I characterize a tractable subclass of non-Markov Equilibria and explain why allowing players to coordinate on payoff-irrelevant events can improve eciency on top of the unique MPE and the exogenous information benchmark. When the intermediary can commit, her optimal Markov disclosure policy has a deadline, after which no breakthrough will be disclosed. However, deadlines are not incentive compatible in the game without commitment, illustrating a time inconsistency problem faced by the intermediary. My model can be applied to professional service industries, such as law and consulting. My results provide an explanation to the observed wage and promotion patterns in Baker, Gibbs and Holmström (1994). In Chapter 3, I study repeated games in which a patient long-run player (e.g. a rm) wishes to win the trust of some myopic opponents (e.g. a sequence or a continuum of consumers) but has a strict incentive to betray them. Her benet from betrayal is persistent over time and is her private information. I examine the extent to which persistent private information can overcome this lack-of-commitment problem. My main result characterizes the set of payoffs a patient long-run player can attain in equilibrium. Interestingly, every type's highest equilibrium payoff only depends on her true benet from betrayal and the lowest possible benet in the support of her opponents' prior belief. When this lowest possible benet vanishes, every type can approximately attain her Stackelberg commitment payoff. My finding provides a strategic foundation for the (mixed) Stackelberg commitment types in the reputation models, both in terms of the highest attainable payoff and in terms of the commitment behaviors. Compared to the existing approaches that rely on the existence of crazy types that are either irrational or have drastically dierent preferences, there is common knowledge of rationality in my model, and moreover, players' ordinal preferences over stage game outcomes are common knowledge.