Breaking the law when others do: A model of law enforcement with neighborhood externalities

A standard assumption in the economics of law enforcement is that the probability of a violator being punished depends only on the resources devoted to enforcement. However, it is often true that the productivity of enforcement resources decreases with the number of violators. In this paper, an individual who violates the law provides a positive externality for other offenders because the probability of being punished decreases with the number of individuals violating the law. This externality explains the existence of correlation between individuals’ decisions to break a law. The model evaluates the implications when determining the socially optimal enforcement expenditure, focusing specifically on the case of neighborhood crime. In particular, using a parametrized functional form, I show that neighborhood externalities will enhance or impede enforcement, depending on the crime rate.     

A contest with the taxman - the impact of tax rates on tax evasion and wastefully invested resources

We develop a moral hazard model with auditing where both the principal and the agent can influence the probability that the true state of nature is verified. This setting is widely applicable for situations where fraudulent reporting with costly state verification takes place. However, we use the framework to investigate tax evasion. We model tax evasion as a concealment-detection contest between the taxpayer and the authority. We show that higher tax rates cause more evasion and increase the resources wasted in the contest. Additionally, we find conditions under which a government should enforce incentive compatible auditing in order to reduce wasted resources.     

Learning about compliance under asymmetric information

Over time, inspection agencies gather information about firms’ pollution levels and this information may allow agencies to differentiate their monitoring strategies in the future. If a firm is less successful than its peers in reducing emissions, it faces the risk of being targeted for increased inspections in the next period. This risk of stricter monitoring might induce high-abatement cost firms to mimic low-abatement cost firms by choosing lower emission levels, while the latter might try to avoid being mimicked. We explain firms’ compliance decisions and the inspection agency's monitoring strategy by means of a signaling game which incorporates dynamic enforcement and learning. Interestingly, we show that the ongoing signaling game between firm types might lead to firms over-complying with the emission standard.     

Learning about the arrival of sales

We analyse optimal stopping when the economic environment changes because of learning. A primary application is optimal selling of an asset when demand is uncertain. The seller learns about the arrival rate of buyers. As time passes without a sale, the seller becomes more pessimistic about the arrival rate. When the arrival of buyers is not observed, the rate at which the seller revises her beliefs is affected by the price she sets. Learning leads to a higher posted price by the seller. When the seller does observe the arrival of buyers, she sets an even higher price.     

The strength of weak ties in crime

The aim of this paper is to investigate whether weak ties play an important role in explaining criminal activities. We first develop a model where individuals learn about crime opportunities by interacting with other peers. These interactions can take the form of either strong or weak ties. We find that increasing the percentage of weak ties induces more transitions from non-crime to crime and thus the crime rate in the economy increases. This is because, when the percentage of weak ties is high, delinquents and non-delinquents are in close contact with each other. We then test these predictions using the U.S. National Longitudinal Survey of Adolescent Health (AddHealth), which contains unique detailed informations on friendship relationships among teenagers. The theoretical predictions of our model are confirmed by the empirical analysis since we find that weak ties, as measured by friends of friends, have a positive impact on criminal activities.     

Multidimensional mechanism design: Revenue maximization and the multiple-good monopoly

The seller of N distinct objects is uncertain about the buyer's valuation for those objects. The seller's problem, to maximize expected revenue, consists of maximizing a linear functional over a convex set of mechanisms. A solution to the seller's problem can always be found in an extreme point of the feasible set. We identify the relevant extreme points and faces of the feasible set. We provide a simple algebraic procedure to determine whether a mechanism is an extreme point. We characterize the mechanisms that maximize revenue for some well-behaved distribution of buyer's valuations.     

Monopoly pricing with negative network effects: The case of vaccines

We study the market for vaccinations considering income heterogeneity on the demand side and monopoly power on the supply side. A monopolist has an incentive to exploit the external effect of vaccinations and leave the poor susceptible in order to increase the willingness to pay the rich. Even the possibility of price discrimination does not remove this incentive. We demonstrate that the weaknesses of standard policy measures are mitigated when income heterogeneity is taken into account. This offers an efficiency based rationale for distribution oriented national or international public health interventions.     

Employment with connections: Negative network effects

In less developed countries, it is widely observed that employers hire workers through employee referrals. In this paper, we show an extension of this kind of networks that may decrease applicants' payoffs while a diversification of the networks can raise referred applicants' payoffs. We also discuss the effect of the extension of interlinked contracts on farmers' wages.     

The real puzzle of blackmail: An informational approach

The “puzzle” of blackmail is that threats to reveal private information that would be harmful to someone in exchange for money are illegal, but revelation is not. The resolution is that concealment of information about product quality impedes the efficient operation of markets, whereas revelation promotes it. The real puzzle is why possessors are not naturally inclined to sell to uninformed parties, who value the information more than would-be blackmail victims. The answer has to do with the public good qualities of information, which create an appropriability problem in transactions with uninformed parties. The paper also discusses incentives to acquire compromising information.     

Job protection laws and agency problems under asymmetric information

Under symmetric information, a job protection law which says that a principal who has hired an agent today must also employ him tomorrow can only reduce the two parties’ total surplus. The law restricts the principal's possibilities to maximize her profit, which equals the total surplus, because she leaves no rent to the agent. However, under asymmetric information, a principal must leave a rent to her agent, and hence profit maximization is no longer equivalent to surplus maximization. Therefore, a job protection law can increase the expected total surplus by restricting the principal's possibilities to inefficiently reduce the agent's rent.     

Information-constrained optima with retrading: An externality and its market-based solution

This paper studies the efficiency of competitive equilibria in environments with a moral hazard problem and unobserved states, both with retrading in ex post spot markets. The interaction between private information problems and the possibility of retrade creates an externality, unless preferences have special, restrictive properties. The externality is internalized by allowing agents to contract ex ante on market fundamentals determining the spot price or interest rate, over and above contracting on actions and outputs. Then competitive equilibria are equivalent with the appropriate notion of constrained Pareto optimality. Examples show that it is possible to have multiple market fundamentals or price-islands, created endogenously in equilibrium.     

Asymmetric information may protect the commons: The welfare benefits of uninformed regulators

We examine an entry-deterrence model in the commons. We investigate in which contexts asymmetric information among firms becomes welfare improving, and in which settings an uninformed regulator may prefer to assess and disseminate information about the available stock among firms.     

Optimal supervision intensity, collusion, and the organization of work

Abstract.  The intensity of supervision, defined as the proportion of supervisors to bottom-rank productive workers, differs widely across organizations and nations. Analysing three monitoring systems that differ in their supervision intensity, I show that the possibility of collective shirking arrangements can impose a system-dependent limit on the range of implementable performances. This brings about a tradeoff in the choice of the monitoring system: the system that economizes on incentive costs may implement an inferior range of performances. Applications of the model generate work-disutility-, ethics- and job-characteristics-based explanations for variations in the intensity of supervision.     

Beneficial collusion in corruption control: The case of nonmonetary penalties

We analyze a corruption model where a principal seeks to control an agent's corruption by supplementing a costless noncollusive outside detector such as the media with a collusive internal supervisor. The principal's objective is to minimize the overall costs, made up of enforcement costs and social costs of corruption. If the penalties on the corrupt agent and a failing supervisor are nonmonetary in nature and yet the two parties can engage in monetary side-transfers, the principal may stand to benefit by allowing supervisor–agent collusion. This benefit may even prompt the principal to actively encourage collusion by hiring a dishonest supervisor in strict preference over an honest supervisor.     

Mechanism design with side payments: Individual rationality and iterative dominance

We investigate the collective decision with incomplete information and side payments. We show that a direct mechanism associated with the social choice function that satisfies budget balancing, incentive compatibility, and interim individual rationality exists for generic prior distributions. We consider the possibility that a risk-averse principal extracts full surplus in agency problems with adverse selection. With regard to generic prior distributions, we show that there exists a modified direct mechanism associated with the virtual social choice function, which satisfies budget balancing and interim individual rationality, such that truth telling is the unique three times iteratively undominated message rule profile.     

Structural estimation of congestion costs

We estimate a structural model of congestion costs using a Bayesian Nash equilibrium approach: The individual's preference for traveling depends on the anticipated level of congestion, which in turn is determined by travelers’ decisions of mobility. The model is estimated using a French transportation household survey. Results confirm the presence of incomplete information and show that aversion to congestion is 6.6% lower during peak times than during off-peak times. A traveler's willingness-to-pay to save 1 min in traffic is estimated at 0.73 euros during peak times and 0.25 euros during off-peak times.     

Environmental regulation of technically inefficient firms

This paper presents a model in which a technically inefficient firm is responsible for the emissions of pollutants. We derive second-best regulatory schemes (tax and quota) assuming that the firm’s technical efficiency is unknown to the regulator.     

Motivation crowding in environmental protection: Evidence from an artefactual field experiment

This paper examines how motivation, crowding and social image affect environmental conservation decisions. An artefactual field experiment conducted in Bolivia is used to reproduce the trade-off between individual and social benefits in natural resource use and test the effect of non-monetary and non-regulatory incentives on pro-social behavior for environmental conservation. The results show the presence of a social norm prescribing positive contribution towards environmental protection, and that external incentives have heterogeneous effects on pro-social behavior depending on how they influence reputation and self-image. The experimental results differ from those of analogous experiments conducted in the laboratory, and are instead consistent with those from field experiments on common-pool resource management. This fact suggests caution in generalizing conclusions, reached in the laboratory, to different settings and populations.     

Existence of equilibrium in large double auctions

We show the existence of a pure strategy, symmetric, increasing equilibrium in double auction markets with correlated, conditionally independent private values and many participants. The equilibrium we find is arbitrarily close to fully revealing as the market size grows. Our results provide strategic foundations for price-taking behavior in large markets.     

The informational effects of competition and collusion in legislative politics

We use a mechanism design approach to study the organization of interest groups in an informational model of lobbying. Interest groups influence the legislature only by communicating private information on their preferences and not by means of monetary transfers. Interest groups have private information on their ideal points in a one-dimensional policy space and may either compete or adopt more collusive behaviors. Optimal policies result from a trade-off between imposing rules which are non-responsive to the groups' preferences and flexibility that pleases groups better. Within a strong coalition, interest groups credibly share information which facilitates communication of their joint interests, helps screening by the legislature and induces flexible policies responsive to the groups' joint interests (an informativeness effect). Competing interest groups better transmit information on their individual preferences (a screening effect). The socially and privately optimal organization of lobbying favors competition between groups only when their preferences are not too congruent with those of the legislature. With more congruence, a strong coalition is preferred. Finally, within a weak coalition, interest groups must design incentive compatible collusive mechanisms to share information. Such weak coalitions are always inefficient.