MASSACHUSETTS INSTITUTE OF TECHNOLOGY HARRY DI PEI harrydp@mit.edu OFFICE CONTACT INFORMATION 77 Massachusetts Avenue, E52-301 harrydp@mit.edu http://economics.mit.edu/grad/harrydp MIT PLACEMENT OFFICER Professor Ben Olken 617-253-6833 bolken@mit.edu HOME CONTACT INFORMATION 50 Cherry Street, Apartment #1 Somerville, MA 02144 Mobile: 617-513-8892 MIT PLACEMENT ADMINISTRATOR Ms. Eva Konomi evako@mit.edu 617-253-8787 Mr. Thomas Dattilo dattilo@mit.edu 617-324-5857 DOCTORAL STUDIES Massachusetts Institute of Technology (MIT) PhD, Economics, Expected completion June 2018 DISSERTATION: Essays in Dynamic Games and Reputations DISSERTATION COMMITTEE AND REFERENCES PRIOR EDUCATION Professor Daron Acemoglu 77 Massachusetts Avenue, E52-446 617-253-1927 daron@mit.edu Professor Juuso Toikka 77 Massachusetts Avenue, E52-556 617-324-3666 toikka@mit.edu Toulouse School of Economics Master in Economics Tsinghua University Bachelor in Mathematics Professor Drew Fudenberg 77 Massachusetts Avenue, E52-418 617-715-4582 drewf@mit.edu Professor Alexander Wolitzky 77 Massachusetts Avenue, E52-558 617-324-6779 wolitzky@mit.edu 2011-13 2007-11 CITIZENSHIP China GENDER: Male LANGUAGES FIELDS English (fluent), Chinese (native) Primary Field: Theory Secondary Fields: Organizational Economics, Political Economy
OCTOBER 2017 -- PAGE 2 TEACHING EXPERIENCE RELEVANT POSITIONS 14.123 Microeconomics III: Decision Theory Teaching Assistant to Professor Drew Fudenberg 14.281 Contract Theory Teaching Assistant to Professor Juuso Toikka 14.12 Economic Applications of Game Theory Teaching Assistant to Professor Muhamet Yildiz 14.283 Advanced Organizational Economics Teaching Assistant to Professor Bengt Holmström 14.282 Organizational Economics Teaching Assistant to Professor Michael Whinston Research Assistant to Professor Alexander Wolitzky Research Assistant to Professor Drew Fudenberg Research Assistant to Professor Daron Acemoglu Research Assistant to Professor Jean Tirole Research Assistant to Professor Christian Hellwig 2017 2014-16 2016 2015 2014 2017 2016 2014-15 2013 2012-13 FELLOWSHIPS, HONORS, AND AWARDS PROFESSIONAL ACTIVITIES JOB MARKET PAPER Best TA of the Year Award 2017 Ho-Ching and Han-Ching Scholarship, MIT 2016 Fellowship 2013-15 Jean-Jacques Laffont Fellowship, Toulouse School of Economics 2011-13 Zheng Geru Fellowship, Tsinghua University 2010 Referee: Econometrica, Review of Economic Studies, Journal of the European Economic Association, Journal of Law Economics and Organization, Journal of Economic Behavior and Organization. Presentations: Western Economic Association Graduate Student Workshop (2017) Stanford Institute of Theoretical Economics (SITE 2016) Norms, Actions and Games Workshop in Toulouse (2016) American Economic Association Annual Meeting (2013, 2015) Reputation Effects under Interdependent Values 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 trade-off 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
OCTOBER 2017 -- PAGE 3 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. PUBLICATIONS When Does Restricting Your Opponent's Freedom Hurt You? Games and Economic Behavior, 100, November 2016. I examine the payoff consequences for a player when she removes a subset of her opponent's actions before playing a two-player complete information normal form game. When she faces a constraint on the maximal number of actions she can remove, she can be strictly better off by not removing any actions. I present such an example. I also establish sufficient conditions under which removing opponent's actions cannot hurt. As a corollary, I also characterize a necessary condition for a player's optimal Nash Equilibrium in games with generic payoffs when her opponent has strictly more actions than she does. Communication with Endogenous Information Acquisition, Journal of Economic Theory, 160, December 2015. I develop a theory of communication in which a sender gathers costly information before giving advice to a receiver. In a general setting, I show that the sender always communicates all her information to the receiver in every equilibrium. In the uniform-quadratic model in which the sender can choose any finite partition as her information structure, an upwardly biased sender can convey more precise information when recommending a larger action. RESEARCH PAPERS Reputation with Strategic Information Disclosure 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 efficiency 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). Trust and Betrayals: Repeated Interaction without Commitment I study situations in which a large player (for example, a government or a seller) wishes to win the trust of many small players (for example, citizens or buyers) but has a strict incentive to betray their trust. I examine the extent to which repeated interactions can overcome this lack-of-commitment problem and
OCTOBER 2017 -- PAGE 4 improve the large player's payoff. In the complete information benchmark, the large player's equilibrium payoff is bounded away from her Stackelberg payoff. When the large player s benefit from betrayal is her private information, the highest equilibrium payoff she can attain only depends on her true benefit from betrayal and the lowest possible benefit according to small players' prior belief. When the lowest possible benefit vanishes, every type can approximately obtain her Stackelberg payoff. I explain the differences between my model and the canonical reputation models in which the large player can be a commitment type that is mechanically playing the same action (pure or mixed) in every period. The main technical contribution is a constructive proof of the large player s limiting equilibrium payoff set. My approach can be generalized to study other repeated Bayesian games with private values and monotone-supermodular stage game payoffs. Monotone Equilibria in Signaling Games (with Shuo Liu) We study the monotonicity of sender's equilibrium strategy with respect to her type in signaling games. We use counterexamples to show that when the sender's payoff is non-separable, the Spence-Mirrlees condition cannot rule out equilibria in which the sender uses non-monotone strategies. These equilibria can survive standard refinements as incentives are strict and the sender plays every action with positive probability. We provide sufficient conditions under which the sender's strategy is monotone in every Nash equilibrium. Our conditions require the sender's payoff to have strictly increasing differences between the state and the action profile and monotone with respect to each player's action. We also identify and fully characterize a novel property on the sender's payoff that is called increasing absolute differences over distributions, under which every pair of distributions over the receiver's actions can be ranked endogenously. Our sufficient conditions fit into a number of applications, which include advertising, warranty provision, education and job assignment, etc. Uncertainty about Uncertainty in Communication (revise and resubmit, Games and Economic Behavior) I study the impact of higher order uncertainty on communication outcomes when the sender's (he) preference is unknown to the receiver (she) and players have no conflict of interest with positive probability. When there is no higher order uncertainty, there exists an equilibrium in which the congruent sender can fully reveal his information conditional on not pooling with non-congruent ones. This is no longer true when the sender faces second order uncertainty. I show that in every equilibrium, the probability with which the sender fully reveals the state is zero. My proof uses a novel contagion argument, which exploits the interactions between higher order uncertainty, the sender's indifference conditions and the receiver's sequential rationality constraints. RESEARCH IN PROGRESS Constitutional Design: An Optimal Delegation Approach (with Daron Acemoglu) We study the optimal regulation of principal-agent relationships without monetary transfers. We model this as a hierarchical optimal delegation problem in which a benevolent designer specifies a set of permissible delegation sets (or a constitution) behind the veil of ignorance, and the principal offers one of them
OCTOBER 2017 -- PAGE 5 to the agent after observing the payoff environment. Constitutional design trades off the gains from adapting the delegation set to the payoff environment and protecting the agent against the principal's exploitation. Our result provides sufficient conditions under which it is without loss of generality to focus on constitutions that respect the following freedom principle: whenever a delegation set is permissible, any superset of it is also permissible. As a result, designing the optimal constitution is equivalent to designing a guaranteed payoff schedule for the agent, making it tractable to characterize. Our optimal constitution is robust in the sense that it does not depend on the designer's prior belief about the payoff environment. Equilibrium Payoffs in Repeated Games with Interdependent Values I characterize the limiting equilibrium payoff set in repeated Bayesian games between a patient long-run player and a sequence of short-run players. The longrun player has private information about a persistent state that directly affects the short-run players payoffs. The key assumption is that the stage game has monotone-supermodular payoffs. I show the sufficient part by constructing a class of sequential equilibria that can arbitrarily approximate every extreme point of the limiting equilibrium payoff set when the long-run player is patient. I show the necessity part by defining two linear programs based on the short-run player s myopic incentives under her prior belief. The values of these programs provide upper and lower bounds on the long-run player s Nash equilibrium payoff when she is sufficiently patient.