Dissertation abstract: Contribution to a public good - Theoretical analysis and experimental evidence

The work undertook is located between Public Economic Theory and Experimental Economics. The object of the thesis consists in analysing the aggregate behavior and the individual heterogeneity in a voluntary contribution game. The thesis defended here is that overcontribution in comparison to the Nash equilibrium of the game, can not be explained neither by judgement errors, nor by the information on the individual behaviour of the members in a one given group. The level of contribution observed remains nevertheless inferior to the one simulated using the E.W.A. learning model. The dissertation is composed of three parts and six chapters. The first chapter expresses the various theoretical mechanisms of production of a public good, while the second one presents an overview of the experimental literature using voluntary contribution mechanisms. The second part carries on the introduction of an interior solution in a public good game in order to distinguish an explanation of overcontribution in terms of mistakes or strategies. While chapter three presents the most important works in literature that use an interior solution, the fourth chapter constitutes a personal contribution consisting in an experiment with an interior optimum. Our main result is that individuals contribute a constant part of their social optimum and that overcontribution is not explained by error. We test then the simple learning model R.L. using the observed data on the aggregate level. This model predicts well the observed behaviour. The third part is composed of two experiments where the environment of players is modified. We introduce in chapter five promises as cheap talk and find that they increase contributions at the aggregate level. In chapter six, various conditions of information on individual contributions are tested. The parameter tested is the level of information on “neighbours” contributions given to players. One of the treatments presents full information about individual contributions of the members of the group, while this information is incomplete in the other treatments. Our results show that information has no effect on the level of contribution. We simulate then the EWA learning model both at the aggregate and the individual levels and compare the simulated data to the experimental one. These simulations predict a level of contribution that is higher that the one observed in the experiment. JEL Classification C91, C92, H41 Dissertation Committee: Alan Kirman (Ph.D. Advisor), Université d’Aix-Marseille III Marie-Claire Villeval (Chair), GATE, Lyon, France Jordi Brandts, Universitat Autonoma Barcelona, Spain Charles Noussair, Emory University, Alanta, GA, U.S.A. Sylvie Thoron, GREQAM & Université du Var, France Marc Willinger, Université de Montpellier I, France     

Providing global public goods under uncertainty

We study how uncertainty and risk aversion affect international agreements to supply global public goods. We consider a benchmark model with homogeneous countries and linear payoffs. When countries directly contribute to a public good, uncertainty tends to lower signatories' efforts but may increase participation. Despite risk aversion, uncertainty may improve welfare. In contrast, when countries try to reduce a global public bad, uncertainty tends to increase signatories' efforts and decrease participation. In that case, an ex-ante reduction of uncertainty may have a large positive multiplier effect on welfare.     

Discrete public goods under threshold uncertainty

A discrete public good is provided when total contributions exceed the contribution threshold, yet the threshold is often not known with certainty. I show that the relationship between the degree of threshold uncertainty and equilibrium contributions and welfare is not monotonic. For a large class of threshold probability distributions, equilibrium contributions will be higher under increased uncertainty (e.g., a mean-preserving spread) if the public good's value is sufficiently high. Otherwise, and if another condition on the distribution's mode is met, contributions will be lower. The same result also obtains if a single-crossing condition of the pdfs is met.     

The evaluation of public investments under uncertainty

In this paper we revise and extend the theory of the evaluation of public investments under uncertainty. Precisely, we argue that the value of the investments that the public sector would be willing to undertake is never below its market value, and that it can be higher if it provides social insurance.     

One-sided provision of a public good through bargaining under representative democracy

We examine a trade-off between strategic delegation and the internalization of interregional externalities through bargaining in the context of political economy. We show that in the case of one-sided provision of a public good, if the public good produced by one region generates a sufficiently significant spillover to another region, then interregional negotiation increases the total surplus of the entire economy.     

Willingness-to-pay for urban ecosystem services provision under objective and subjective uncertainty

There is growing concern that failure to acknowledge the risk and uncertainty surrounding ecosystem services (ES) delivery could have adverse effects on support for ES policy intervention in the long run. However, acknowledging risk may reduce support for policy interventions in the short term. In this paper, we sought to determine whether willingness-to-pay (WTP) for urban forest ES in Southampton, UK is affected by objective and subjective uncertainty surrounding ES delivery. We conducted a discrete choice experiment with a split sample design: one with a scenario specifying risky ES outcomes and one where zero risk was implied. Respondents’ subjective certainty surrounding the provision of ES was determined before and after the choice questions. Despite respondents’ risk aversion, introducing an objective likelihood attribute did not reduce WTP compared to the scenario with implied certain ES outcomes. Furthermore, whilst WTP for the overall scheme was found to be adversely affected by the presence of risk around ES outcomes, subjective uncertainty seemed to reduce WTP more than objective probabilities. Our results therefore support the idea that both objective probabilities and subjective uncertainty should be explicitly incorporated in the design of stated preference studies for ES valuation.     

Government Ponzi games and the sustainability of public deficits under uncertainty

This paper reconsiders the conditions under which a government may engage in debt roll-over schemes by financing interest payments through the issue of new debt. Output growth rates in excess of interest rates on government debt have traditionally been considered grounds for sustaining such schemes. A government may avoid debt repayment, or even run a primary deficit forever, and yet maintain a bounded debt-to-income ratio. Recent research has pointed at the stronger constraints placed on government behaviour by uncertain output growth. We show that this is not the case when an alternative criterion for solvency is used, namely that the debt-to-income ratio converges almost surely in the long run. In this case, the government is solvent when the asymptotic growth rate of the economy exceeds the asymptotic interest rate on debt, a natural extension of a familiar criterion in a deterministic environment.Convergence to the long-run outcome may, however, be a slow process. For realistic parameter values, long-run-stable fiscal plans may resemble unsustainable plans over long horizons. This circumstance may explain the observed poor performance of debt ratios as indicators of fiscal sustainability.     

Democratic public good provision

This paper analyzes an overlapping generation model of redistribution and public good provision under repeated voting. Expenditures are financed through age-dependent taxation that distorts human capital investment. Taxes redistribute income both across skill groups and across generations. We focus on politico-economic Markov equilibria and contrast these with the Ramsey allocation under commitment. The model features indeterminate equilibria, with a key role of forward-looking strategic voting. Due to the lack of commitment to future policies, the tax burden may be on the wrong side of the dynamic Laffer curve. Moreover, restrictions on government policies can in some cases be welfare improving.     

Voluntary contributions to a public good when partial contribution is a dominant strategy

We present an experiment on voluntary contributions to a public good. The game has a dominant strategy solution in the interior of the strategy space. We observe significant over-contribution. Our result is similar to those of typical corner-solution experiments.     

Quality uncertainty and time inconsistency in a durable good market

In a durable good monopoly where consumers cannot observe quality prior to purchase and product improvement occurs exogenously over time, I show that uncertainty in quality may resolve the time inconsistency problem (even for low levels of product improvement). Higher dispersion in quality creates greater demand for future product by increasing the incentive of buyers with inferior quality realizations to repeat purchase and this, in turn, reduces the incentive of the seller to cut future price. For various levels of product improvement, I characterize the range of quality uncertainty for which the market equilibrium is identical to one where the monopolist can credibly precommit to future prices. I also show that the presence of quality uncertainty can lead to no trading in the primary good market. Further, in contrast to the literature on the Coase conjecture, inability to precommit to future prices can reduce social welfare as a result of the market closure.     

The company you keep: Qualitative uncertainty in providing a club good

Clubs are typically experience goods. Potential members cannot ascertain precisely beforehand their quality (dependent endogenously on the club's facility investment and number of users, itself dependent on its prices). Members with unsatisfactory initial experiences discontinue visits. We show that a monopoly profit maximizer never offers a free trial period for such goods. For quality functions homogeneous of degree of at least minus one, a welfare maximizer, motivated by distributional concerns to mitigate disappointed consumers' losses, always does. We demonstrate the robustness of this finding by showing that (i) without qualitative uncertainty (thus, no disappointed customers), neither welfarist nor monopolist offers free trials; and (ii) if the planner pursues an objective mixing welfare maximization with profit maximization, the likelihood of free trials increases with the weight put on welfare maximization. Regarding club quality and usage, the monopolist provides a socially excessive level of quality to repeat buyers when the quality function is homogeneous of degree zero. With nonhomogeneous quality functions, the monopolist permits too little club usage; quality may or may not be socially excessive.     

Favor trading in public good provision

Favor trading is common. We do something nice for someone and they do something nice in return. Several motives might underlie such behavior, including altruism, strategic motives, and direct or indirect positive reciprocity. It is not yet well-understood how these fit together to affect behavior, how they interact in various institutional structures, and how they play out over time. We use a laboratory experiment to study the elements and dynamics of favor trading in a particular setting: the private provision of a public good. In our experiment, giving subjects the ability to practice targeted reciprocity by making a simple, low-cost change in information provision increases contributions to the public good by 14 %. Subjects reward group members who have previously been generous to them and withhold rewards from ungenerous group members. Strategic concerns cannot explain all of this behavior, and it must be at least partly due to direct reciprocity. When someone cannot directly benefit from favor trading, he gives much less to the public good. People thus excluded from the “circle of reciprocity” provide a clean and strict test of indirect reciprocity. Contrary to previous studies in the literature, we do not observe indirect reciprocity.     

Social capital as a public good and an oscillatory behaviour

In this study, we investigate optimal dynamics in a two-sector model in which the capital good is a public good. We obtain a sufficient condition under which optimal dynamics in fact follows non-linear dynamics, involving period-2 cycles and a tentshaped transition function.     

Private investment with social benefits under uncertainty: The dark side of public financing

We develop a game‐theoretic model of private–public contribution to a long‐term project with sequential actions and moral hazard. A private agent is one who is in charge of both the financial contribution and the management effort, these two actions entailing private costs and uncertain ex‐post private and social benefits. A public agent is one who decides the amount of public funding to this quasi‐public good, knowing that the size and the probability of attaining a surplus ex post depend on the private agent's effort. We consider four public‐funding scenarios: benefit‐sharing versus cost‐sharing crossed with ex‐ante versus ex‐interim government intervention. We test our theoretical predictions by means of an experiment that confirms the main result of the model: Cost‐sharing public intervention is more effective than benefit‐sharing in boosting private financial contribution to the project. Furthermore, when public intervention comes after private contribution ( ex‐interim government intervention), both public‐funding scenarios have a negative impact on the private management effort. In our model, the latter result is explained by the private agent's high degree of risk aversion. These results have policy implications for strategic investments with long‐term social consequences. In deciding the optimal timing and method of the contribution, governments should also consider the indirect effects on agents’ long‐term management efforts.     

Giving at the close: Experimental evidence on cooperation in contributing to a public good

We present a simple dynamic model of contributions to a public good. We test the model by conducting a public good game experiment and fundraising experiment among religious Jewish students for the procurement of sustainable supplies for their campus synagogue. The results of the experiments show a high level of cooperation; particularly, the results of the public good experiment show that contributions are above the predicted optimum. Nevertheless, in accordance with the economic theory, we find that the contribution path is upward sloping and contributions increase with the benefit of the public good. Our findings also suggest that the level of contributions and their path are affected by peer and gender effects.