The Dynamic Pivot Mechanism

We consider truthful implementation of the socially efficient allocation in an independent private‐value environment in which agents receive private information over time. We propose a suitable generalization of the pivot mechanism, based on the marginal contribution of each agent. In the dynamic pivot mechanism, the ex post incentive and ex post participation constraints are satisfied for all agents after all histories. In an environment with diverse preferences it is the unique mechanism satisfying ex post incentive, ex post participation, and efficient exit conditions. We develop the dynamic pivot mechanism in detail for a repeated auction of a single object in which each bidder learns over time her true valuation of the object. The dynamic pivot mechanism here is equivalent to a modified second price auction.     

Efficiency in Games With Markovian Private Information

We study repeated Bayesian games with communication and observable actions in which the players' privately known payoffs evolve according to an irreducible Markov chain whose transitions are independent across players. Our main result implies that, generically, any Pareto‐efficient payoff vector above a stationary minmax value can be approximated arbitrarily closely in a perfect Bayesian equilibrium as the discount factor goes to 1. As an intermediate step, we construct an approximately efficient dynamic mechanism for long finite horizons without assuming transferable utility.     

Dynamic Mechanism Design: A Myersonian Approach

We study mechanism design in dynamic quasilinear environments where private information arrives over time and decisions are made over multiple periods. We make three contributions. First, we provide a necessary condition for incentive compatibility that takes the form of an envelope formula for the derivative of an agent's equilibrium expected payoff with respect to his current type. It combines the familiar marginal effect of types on payoffs with novel marginal effects of the current type on future ones that are captured by “impulse response functions.” The formula yields an expression for dynamic virtual surplus that is instrumental to the design of optimal mechanisms and to the study of distortions under such mechanisms. Second, we characterize the transfers that satisfy the envelope formula and establish a sense in which they are pinned down by the allocation rule (“revenue equivalence”). Third, we characterize perfect Bayesian equilibrium‐implementable allocation rules in Markov environments, which yields tractable sufficient conditions that facilitate novel applications. We illustrate the results by applying them to the design of optimal mechanisms for the sale of experience goods (“bandit auctions”).     

Clustering Finnish Gambler Profiles Based on the Money and Time Consumed in Gambling Activities

Gambling involves consumption of gamblers’ money and time. Gamblers are a heterogeneous group, and in addition to grouping gamblers based on personality factors, it is also important to find different gambler profiles with respect to their gambling behavior. Using the nationally representative survey ‘Finnish Gambling 2011’ (N = 4484), this article studies the subtypes of Finnish gamblers based on the frequency of gambling and the amounts of money and time used in different gambling forms. Cluster analysis reveals six profiles of gamblers, from infrequent gamblers to omnivorous gamblers. In the further analysis of the clusters, it was found that the highest problem gambling prevalence was in the groups of sport betting + electronic gaming machine gamblers and omnivorous gamblers, which were also both dominated by men. Certain gambling consumption patterns and risk factors for problem gambling are related to both socio-demographic backgrounds of the gamblers as well as the structural and situational characteristics of the games. The results have implications for the prevention of problem gambling, as some consumption patterns may be connected with the probability of developing gambling problems.     

GETTING IT DONE: DYNAMIC INCENTIVES TO COMPLETE A PROJECT

A principal wants an agent to complete a project. The agent undertakes unobservable effort, which affects in each period the probability that the project is completed. We characterize the contracts that the principal sets, with and without commitment. With full commitment, the contract involves the agent's value and wage declining over time, in order to give the agent incentives to exert effort. The best sequentially rational equilibrium for the principal also involves the agent's wage declining over time, while the worst sequentially rational equilibrium for the principal has a constant wage (and is in fact the unique stationary equilibrium). The best (weakly) renegotiation‐proof equilibrium for the principal is achieved by a constant wage that maximizes the principal's payoff, conditional on wages being constant. We compare these solutions to the efficient outcome.     

INFORMATION ACQUISITION IN INTERDEPENDENT VALUE AUCTIONS

We consider an auction environment with interdependent values. Each bidder can learn her payoff type through costly information acquisition. We contrast the socially optimal decision to acquire information with the equilibrium solution in which each agent has to privately bear the cost of information acquisition. In the context of the generalized Vickrey‐Clarke‐Groves mechanism, we establish that the equilibrium level exceeds the socially optimal level of information with positive interdependence. The individual decisions to acquire information are strategic substitutes. The difference between the equilibrium and the efficient level of information acquisition is increasing in the interdependence of the bidders' valuations and decreasing in the number of informed bidders. (JEL: C72, C73, D43, D83)     

Information Acquisition and Efficient Mechanism Design

We consider a general mechanism design setting where each agent can acquire (covert) information before participating in the mechanism. The central question is whether a mechanism exists that provides the efficient incentives for information acquisition ex‐ante and implements the efficient allocation conditional on the private information ex‐post. It is shown that in every private value environment the Vickrey‐Clark‐Groves mechanism guarantees both ex‐ante as well as ex‐post efficiency. In contrast, with common values, ex‐ante and ex‐post efficiency cannot be reconciled in general. Sufficient conditions in terms of sub‐ and supermodularity are provided when (all) ex‐post efficient mechanisms lead to private under‐ or over‐acquisition of information.