Nick Netzer

The logit-response dynamics

We develop a characterization of stochastically stable states for the logit-response learning dynamics in games, with arbitrary specification of revision opportunities. The result allows us to show convergence to the set of Nash equilibria in the class of best-response potential games and the failure of the dynamics to select potential maximizers beyond the class of exact potential games. We also study to which extent equilibrium selection is robust to the specification of revision opportunities. Our techniques can be extended and applied to a wide class of learning dynamics in games.

A Game Theoretic Foundation of Competitive Equilibria with Adverse Selection

We construct a fully specified extensive form game that captures competitive markets with adverse selection. In particular, it allows firms to offer any finite set of contracts, so that cross-subsidization is not ruled out. Moreover, firms can withdraw from the market after initial contract offers have been observed. We show that a subgame perfect equilibrium always exists and that, in fact, when withdrawal is costless, the set of subgame perfect equilibrium outcomes may correspond to the entire set of feasible contracts. We then focus on robust equilibria that exist both when withdrawal costs are zero and when they are arbitrarily small but strictly positive. We show that the Miyazaki-Wilson contracts are the unique robust equilibrium outcome of our game. This outcome is always constrained efficient and involves cross-subsidization from low to high risk agents that is increasing in the share of low risks in the population under weak conditions on risk preferences.

Competitive Markets without Commitment

In the presence of a time-inconsistency problem with agency contracts, we show that competitive markets can implement allocations that Pareto-dominate those achieved by a benevolent government, and they induce more effort. We analyze a model with moral hazard and a two-sided lack of commitment. After agents have chosen their work, firms can modify contracts and agents can switch firms. If the ex post market outcome satisfies a weak notion of competitiveness and sufficiently separates individuals, it is Pareto superior to a government’s allocation with a complete breakdown of incentives. Moreover, competitive markets without commitment implement more effort in equilibrium under general conditions.

Mechanism design and intentions

We introduce intention-based social preferences into a mechanism design framework with independent private values and quasilinear payoffs. For the case where the designer has no information about the intensity of social preferences, we provide conditions under which mechanisms which have been designed under the assumption that agents are selfish can still be implemented. For the case where precise information about social preferences is available, we show that any tension between efficiency, incentive-compatibility, and voluntary participation may disappear. Impossibility results such as the one by Myerson and Satterthwaite (1983) are then turned into possibility results. We also provide a systematic account of the welfare implications of kindness sensations.

Informational Requirements of Nudging

A nudge is a paternalistic government intervention that attempts to improve choices by changing the framing of a decision problem. We propose a welfare- theoretic foundation for nudging similar in spirit to the classical revealed preference approach, by investigating a model where preferences and mistakes of an agent can be elicited from her choices under different frames. We provide characterizations of the classes of behavioral models for which nudging is possible or impossible, and we derive results on the required quantity of information. We also study an extended application to a savings problem.

Does the absence of human sellers bias bidding behavior in auction experiments

This paper studies the impact of the presence of human subjects in the role of a seller on bidding in experimental second-price auctions. Overbidding is a robust finding in second- price auctions, and spite among bidders has been advanced as an explanation. If spite extends to the seller, then the absence of human sellers who receive the auction revenue may bias upwards the bidding behavior in existing experimental auctions. We derive the equilibrium bidding function in a model where bidders have preferences regarding both, the payoffs of other bidders and the seller’s revenue. Overbidding is optimal when buyers are spiteful only towards other buyers. However, optimal bids are lower and potentially even truthful when spite extends to the seller. We experimentally test the model predictions by exogenously varying the presence of human subjects in the roles of the seller and competing bidders. We do not detect a systematic effect of the presence of a human seller on overbidding. We conclude that overbidding is not an artefact of the standard experimental implementation of second-price auctions in which human sellers are absent.

Delegating performance evaluation

We study optimal incentive contracts with multiple agents when performance evaluation is delegated to a reviewer. The reviewer may be biased in favor of the agents, but the degree of bias is unknown to the principal. We show that a contest, which is a contract in which the principal determines a set of prizes to be allocated to the agents, is optimal. By using a contest, the principal can commit to sustaining incentives despite the reviewers potential leniency bias. The optimal effort profile can be uniquely implemented by an all-pay auction with a cap. Our analysis has implications for applications as diverse as the design of worker compensation, the awarding of research grants, and the allocation of foreign aid.