RULLIERE Jean Louis

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In this paper, we propose and study a risk model with two types of claims in which the insurer may invest into a prevention plan which decreases the intensity of large claims without impacting the small claims. We identify a necessary and sufficient condition for insurers to use prevention if there is no surplus. If, in addition, the severity of large claims dominates that of small claims by the harmonic mean residual life (HMRL) order, insurers invest more in prevention in the presence of a surplus. Finally, we characterize the asymptotic optimal prevention strategy when the initial surplus tends to infinity in the two main cases where both claim types are light-tailed and where one of them is light-tailed and the other one is heavy-tailed.

This thesis deals with the implementation of prevention actions financed by an insurance company. It is composed of five chapters preceded by a general introduction which aims to present the difficulties linked to prevention, the tools used and the main results obtained. Chapter 1 proposes a method of unsupervised classification of health insurance policyholders into homogeneous risk groups, based on the benefits paid by an insurance company. This method has two phases: first, a dimension reduction of the data using positive matrix factorizations (PMF) is performed. The classification is then finalized using Kohonen maps. The tests of the method are also presented. The final classes obtained are finally analyzed in order to study whether some of them can be the object of a prevention action. A prevention action on psychiatry is proposed. Chapter 2 is a continuation of Chapter 1 since it focuses on comparing the quality of dimension reduction using NMF methods with that obtained using two other methods, the Word2Vec (W2V) and the marginalized stacked debugger autoencoders (mSDA). In particular, the stability of the final classifications is studied using a new stability measure. A complement on the consideration of temporality with the W2V algorithm is also presented. Chapter 3 proposes a study of the psychiatric risk within a complementary health organization, the algorithms of the previous chapters having allowed to identify this risk. With the help of a statistical study conducted on four databases, it is notably shown that insureds using psychiatry cost on average twice as much to the health insurer as an average individual. Some potential preventive actions are suggested in the conclusion. Chapter 4 focuses on the modelling of prevention within an insurance company. By integrating a prevention parameter into the compound Poisson model derived from the theory of ruin, it is indeed possible to measure the effect of prevention on certain indicators, such as the probability of ruin. Different optimal prevention strategies are proposed, and a sensitivity analysis is provided. Finally, chapter 5 proposes to extend the model considered in the previous chapter to the case where an insurance company is confronted with a light risk and a heavy risk. In such a model, the optimal prevention strategy depends on the amounts of reserves built up. Asymptotic results on the optimal strategies are provided.

In this paper, we propose and study a first risk model in which the insurer may invest into a prevention plan which decreases claim intensity. We determine the optimal prevention investment for different risk indicators. In particular, we show that the prevention amount minimizing the ruin probability maximizes the adjustment coefficient in the classical ruin model with prevention, as well as the expected dividends until ruin in the model with dividends. We also show that the optimal prevention strategy is different if one aims at maximizing the average surplus at a fixed time horizon. A sensitivity analysis is carried out. We also prove that our results can be extended to the case where prevention starts to work only after a minimum prevention level threshold.

This doctoral dissertation focuses on the modeling of preventive effort and its relationship with market insurance. Each chapter attempts to capture different aspects of this problem, from the study of a criterion consistent with actuarial practices to the study of the supply side of insurance, including risk perception biases and an approach to prevention in dynamic time. Chapter 1 models the relationship between an insurer and an insured as a Stackelberg game. In this game, the insurer plays first by offering an insurance contract in the form of a loading factor. The insured then plays by choosing the optimal coverage rate and prevention effort. Both the insured and the insurer aim to minimize their respective risk measures, which are both consistent. The respective effects of self-insurance and self-protection on risk minimization will be studied. In each case, it will be shown that optimal choices for the insured exist and the optimal contract for the insurer will be characterized. Moreover, it will be shown that if the agent's risk measure decreases faster than his loss expectation, then the optimal effort is increasing with the loading factor with a potential discontinuity when the optimal coverage goes from full to zero. However, in the opposite case the optimal effort can be increasing or decreasing with the loading factor. Chapter 2 studies the relationship between self-insurance and market insurance also in the form of an optimization problem for one agent. Similar to Chapter 1, this agent must determine the coverage rate and the prevention effort that will optimally reduce its risk measure. The considered risk measure is called distortional and is defined from a non concave distortion function. This allows for potential individual cognitive biases in risk perception. The characterization of the optimal solution for the agent makes it possible to draw a new conclusion about the relationship between self-insurance and market insurance. Self-insurance is no longer just a substitute for market insurance, but can also be complementary to it, depending on the sensitivity of the prevention effort to the price of insurance. Chapter 3 focuses on self-protection by proposing a dynamic expected utility maximization problem. This takes the form of a stochastic control problem in which the agent chooses his insurance coverage and his prevention effort which is dynamic. The problem can be separated into two subproblems, the first one is an optimization in effort and the second one in insurance coverage. Since the individual wants to obtain the largest possible final wealth, he seeks to maximize the exponential utility expectation of this wealth. The agent's wealth can be seen as the solution of a backward-looking stochastic differential equation with a jump, this equation admits a unique solution and is moreover explicit. In particular, we obtain that the optimal self-protection effort is constant. The initial distribution of the loss process, when there is no effort, is given by a compound Poisson process which is in particular a Lévy process. Obtaining a constant optimal effort means that the Lévy property of the processes is preserved by maximizing an exponential utility expectation. The analysis of the problem in insurance coverage gives a sufficient condition to obtain the existence of an optimal level of coverage. The individual can then subscribe to an insurance policy by providing a preventive effort that will maximize his satisfaction or choose not to subscribe to the policy but by taking part in self-protection actions.

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While the laws are justified on the basis of the efficiency they provide to society, policy makers and researchers focus on the reasons why people violate the law. Crimes and violations induce directly costs. But there is another indirect costs that is generally ignored : the fact that a person can violate the law (whether it does or not) can reduce trust in one's honesty. Thus, even if the economic agent is honest and respects the law, this loss of confidence, which could be unfounded, is also a source of inefficiency. We introduce in an experiment, a normative rule of "decision" in order to elicit both honesty and beliefs about honesty from subjects in the lab. There is no direct transfer of money between both part to avoid any inequality aversion or altruism aversion. The main question remains how individuals trust in the honesty of an anonymous group. Subjects are split into two groups : those who are subject to the temptation of (unverifiable) dishonesty and those who value the dishonesty of others. We inform each participant that we cannot identify defection. We find an important heterogeneity of trust in honesty through subjects. On average, subjects A suggests that participants B are more honest than they are. Moreover, we identify distortion of effective honesty and beliefs about other honesty when the environment of players A is unfavorable.

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In this paper, we propose and study a first risk model in which the insurer may invest into a prevention plan which decreases claim intensity. We determine the optimal prevention investment for different risk indicators. In particular, we show that the prevention amount minimizing the ruin probability maximizes the adjustment coefficient in the classical ruin model with prevention, as well as the expected dividends until ruin in the model with dividends. We also show that the optimal prevention strategy is different if one aims at maximizing the average surplus at a fixed time horizon. A sensitivity analysis is carried out. We also prove that our results can be extended to the case where prevention starts to work only after a minimum prevention level threshold.

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In this paper, we propose and study a risk model with two types of claims in which the insurer may invest into a prevention plan which decreases the large claims intensity without impacting the small claims. In this setting, we prove that prevention is advantageous when claim severities for small and large claims are ordered in the sense of the Harmonic-Mean-Residual-Lifetime (HMRL) order. In addition, we show that the optimal prevention amount is the lowest when there is no initial surplus. Finally, we characterize the asymptotic optimal prevention strategy when the initial surplus tends to infinity in the two main cases where both claim types are light-tailed and where one of them is light-tailed and the other one is heavy-tailed.

On paper, prevention appears to be a good complement to health insurance. However, its implementation is often costly. To maximize the impact and efficiency of prevention plans these should target particular groups of policyholders. In this article, we propose a way of clustering policyholders that could be a starting point for the targeting of prevention plans. This two-step method mainly classifies using policyholder health consumption. This dimension is first reduced using a Nonnegative matrix factorization algorithm, producing intermediate health-product clusters. We then cluster using Kohonen's map algorithm. This leads to a natural visualization of the results, allowing the simple comparison of results from different databases. We apply our method to two real health-insurer datasets. We carry out a number of tests (including tests on a text-mining database) of method stability and clustering ability. The method is shown to be stable, easily-understandable, and able to cluster most policyholders efficiently.

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The objective of this thesis is to analyze the interactions between economic agents operating in the retail insurance market. On the one hand, policyholders wishing to cover themselves against a risk of loss must explore the market in order to subscribe to a contract in line with their perception of the risk. On the other hand, insurers compete in a regulated market, imposing on them a certain level of capital in order to guarantee their solvency in a context of uncertainty about the risks underwritten. On the other hand, intermediaries offer their services in order to facilitate the interaction between consumers, who are averse to risk, and firms, which take risks. It is therefore in this context that we analyze the behavior of insurance actors from different perspectives. Chapters 1 and 2 of this thesis are the result of laboratory experiments, carried out using a web interface designed specifically for these studies. The results in Chapter 3 are based on a theoretical model and numerical simulations. Chapter 1 focuses on the relationship between honesty and honesty beliefs of economic agents. Using data collected in the laboratory, we show how uncertainty and the feeling of being in more or less advantageous conditions impact both the level of honesty and the belief in honesty towards others. In general, consumers overestimate the honesty of intermediaries. Thus, this result justifies their presence in the insurance market. On the other hand, we also show that the financial incentives offered to intermediaries distort honesty beliefs. The lower the incentive level, the more dishonest behavior is anticipated by consumers. In Chapter 2, we highlight the dilemma faced by the consumer in a market with multiple distribution channels. Should he explore by himself and choose among a large set of contracts or delegate part of his decision to an intermediary plus or minus search costs, we show that obfuscation related to a large amount of information and beliefs in the honesty of intermediaries are the main determinants of search and purchase decisions. We also show that obfuscation and intermediaries' attitudes are sources of inefficiency in decision making, in particular with respect to the characteristics of the insurance contracts purchased by consumers. In this sense, the identification of a focus effect supports the importance of the price level in decision making to the detriment of the risk environment and the level of coverage. The introduction of search costs in the exploration process, as well as the heterogeneity of honesty beliefs, justify the multi-channel distribution strategies adopted by insurers. An analysis of a repeated non-cooperative game is presented in Chapter 3 of this thesis where losses and consumer behavior are stochastic and insurers compete on price. In order to incorporate the regulators' constraints, we determine Nash equilibria under solvency constraints. We also analyze the sensitivity of equilibrium premiums to the parameters of the game, in particular when firms do not benefit from the same comparative advantages (i.e. reputation leading to different levels of customer retention, insurers' seniority leading to different capital stocks).

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This paper aims to shed light on the dilemma faced by insurance purchasers faced with multiple distribution channels. Should the consumer herself choose from a large set of insurance policies or rather delegate a part her decision to an intermediary who is more or less honest? We consider decisions based on a number of real-world insurance distribution channels with different information frames. Beliefs about intermediary honesty are the main determinants of individual choice. In addition, the obfuscation of information is the main source of inefficiency in decision-making, particularly regarding the characteristics of the insurance contracts chosen by consumers.

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The auto insurance industry is facing a number of regulatory, financial, behavioral and technological changes. In order to face the challenges resulting from these changes and maintain their profitability, insurers must innovate in terms of pricing. In this context, we develop in this thesis two themes related to automobile insurance pricing. The first theme is based on the optimization of pricing strategies, both in underwriting and renewal. The second theme is oriented towards the use of experiments in order to better understand the determinants of insurance demand. We illustrate how empirical demand models based on data available to the insurer can be used to optimize profitability and customer retention. We then extend the optimization framework by taking into account the inter-temporal dependencies between current rate decisions and profits generated in future periods. Thus, we introduce the Customer Value framework that allows the insurer to adapt its pricing strategy according to policyholders' behaviors over their customer lifetime while taking into account the market cycle. The empirical illustrations in the first two chapters are based on natural data observed by the insurer.In the second part of the thesis, we illustrate the contribution of field and laboratory experiments to the understanding of the demand for automobile insurance. A field experiment allows us to refine the measurement of customer price elasticity and to treat the pricing problem as a contextual bandit problem. Offline evaluation of several reinforcement learning strategies shows that those applying targeted fare experimentation achieve better financial performance compared to the myopic strategy, which excludes any possibility of experimentation. Finally, we present the results of a laboratory experiment whose objective was to measure the added value of private variables from decision models in risk. In particular, we analyze the role of risk aversion and risk perception in explaining car insurance choices. The same experimentation allowed us to analyze the external validity in experimental insurance, i.e. the similarity of individuals' behaviors in an experimental context and in the real economic context of the market.In addition to the experimentation-optimization duality in the field of insurance pricing, this thesis thus illustrates the duality between private data and public data, as well as the duality between empirical models of insurance demand and theoretical models.

In a context where the search for academic excellence is at the heart of the concerns of academic institutions and public authorities, this thesis aims to contribute to the study of the determinants of the scientific production of French professors in economics. By mobilizing original data from teacher-researchers' applications for the "Prime d'Excellence Scientifique", the four proposed contributions seek to articulate two important dimensions, which have rarely been addressed jointly in the literature: the effects of collective externalities in scientific production, and the multitasking nature of teacher-researchers' activity. The first chapter of the thesis analyzes the determinants of the award of the Prime d'Excellence Scientifique (PES) to French professors in economics. We focus on the multitasking character of individual production and the dynamic dimension of this particular form of academic competition implemented since 2009. Econometric results obtained from a sequential model show that scientific publications are the most important determinant of the chances of success in the ESP. We identify discouraging factors during this dynamic tournament. The results also show that past promotion under the previous PEDR scheme increases the promotion chances of teacher-researchers. The second chapter looks at the determining factor in the allocation of the PES and the promotion of teacher-researchers: scientific production. This chapter highlights that the externalities associated with the research environment of teacher-researchers are likely to explain both the individual dynamics of scientific production and the concentration of this production among a small number of teacher-researchers. Our econometric results by quantiles conclude that there are two extreme scientific production regimes: multipurpose and specialist. However, our results do not refute the existence of a scientific production cycle that would be sensitive to the stock of skills accumulated in the work environment of teacher-researchers. Taking into account the potential interactions between teaching and research tasks highlighted in the second chapter, the third chapter proposes to analyze, using a theoretical and econometric model, the effects of the research environment on the choice of activities of teacher-researchers. By controlling for the simultaneity and endogeneity of the choice of teaching and research tasks, the econometric results on our data largely confirm the theoretical predictions: the effects of externalities resulting from the spatial concentration of research and/or training skills at a given time, leads to "typical" profiles of specialists (in research or training) or, on the contrary, "generalists" combining scientific production, pedagogical implications and collective responsibilities. Taking into account the heterogeneity of scientific publications in economics, the fourth chapter analyses the determinants of the "quantity-quality" trade-off in scientific production. In particular, we study the determinants of the choice of two types of publications defined in the CNRS ranking of economics journals: first-ranked publications and second-ranked publications. The econometric results of the joint estimation of these two types of publications conclude that there is a trade-off between good quality publications and publications in less well ranked journals, a trade-off that is sensitive to the externality effects of the research environment of teacher-researchers.

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Designed to promote multidisciplinary fundamental research, the Action Concertée Incitative Ville (ACIV) created by the French Ministry of Research aimed to renew the issues at stake in order to better understand contemporary urban issues, the transformations underway and to anticipate future developments. This book provides an inventory of the research supported during the four years of ACIV programming. The two volumes bring together 143 contributions from "established" teams, "young" researchers, and doctoral students, demonstrating the abundance and richness of themes, issues, methods, and fields. These contributions, which report on research financed by ACIV and the thesis grants it has supported, are organized around six themes: "Urban Forms, Cultures and Modes of", "Social and Civic Cohesion", "Changes in Scale, Recomposition of Territorial Systems and", "Urbanistic Cultures": from the sources of urban history to sustainable urban development", "Physical Environments, Urban Environments and", "Management, Management and Technical Systems". The postface opens up a critical and prospective reflection "for several" on the future of urban research.

This manuscript includes three essays that share the common objective of assessing the impact of self-confidence on economic agents' decisions using the experimental method. This work focuses on three topics related to the behavioral economics of work: moonlighting, job search and teamwork. The first chapter analyzes optimism biases in the context of irregular work. This work provides a measure of optimism bias through a decision process. The results show that the way in which the control is announced alters the perception of risk: the designation of the number of agents randomly controlled tends to encourage the optimism of fraudsters. The second chapter examines how uncertainty about skill and self-esteem affect job seekers' search decisions. The results show that, on average, low-skill agents do not change their reservation wages, while high-skill subjects tend to lower their wage demands and thus stop their search more quickly. However, the decisions of low-skill agents are not homogeneous: low-skill agents have higher wage demands the higher their self-esteem. The third chapter aims to evaluate the extent to which workers' self-image conditions their choice of effort when working in a group. The results show that agents who over- (under-) evaluate their ability exert more (less) effort than subjects who have a correct perception of their skills. The results also reveal that individuals benefit from their partner's overconfidence, but not from their own bias, while underconfidence worsens the well-being of all team members.

This thesis considers generalized agency problems: situations in which the principal faces both an adverse selection and a moral hazard problem. There are two reasons why the principal uses an agent: the agent may have private information that the principal does not observe and the agent may have the power to make decisions that the principal does not directly control. Although most of the literature on incentives treats adverse selection and moral hazard situations separately, these two important features are at work together in a wide variety of economic environments. This thesis is part of a body of work that analyzes how the two types of informational asymmetry interact from two different perspectives. On the one hand, we know that the results on the characterization and existence of optimal contracts, derived from the literature dealing separately with adverse selection and moral hazard, are not directly transposable to a generalized agency framework. The first objective of this thesis is to define a set of sufficient conditions that validate the use of the first order approach. On the other hand, considering the presence of a pre- and post-contractual opportunism problem, the second objective of this thesis is to analyze the way the principal constructs the contract, so as to limit the consequences of both types of informational asymmetry.

Agency theory has provided a thorough analysis of the conditions under which incentives reconcile the divergent interests of the principal and the agent. The essays presented in this dissertation assess the empirical relevance of these results in the face of third-party intervention in three typical situations: corrupt behavior, practice choices of medical specialists, and demand for moonlighting. First, corruption situations correspond to the interweaving of two contracts: a delegation contract, which binds a Principal and an Agent, and a corruption pact concluded between this Agent and a third party, called the Corruptor. We first review the recent literature on this issue, comparing existing results on the determinants of bribery behavior with the properties of each of these two contracts. We then show that the simultaneous existence of these two contracts puts the agent in front of a conflict of reciprocities. The results of the three-player experimental corruption game that we carry out confirm the importance of this mechanism. This reciprocity conflict is at the origin of a delegation effect that constitutes an additional explanation for the influence of the wage on bribery behavior. Second, the management of physicians' supply of care must meet conflicting objectives: controlling the cost of the health care system is the primary concern of the authorities administering it, while patients are primarily concerned with the quality of care (in terms of health). To better understand the ability of incentives to resolve this contradiction, we propose a theoretical and econometric analysis of the effects of the introduction of mixed remuneration in Quebec in 1999. Physicians' behaviour is described by their choices in terms of extensive margins (number of hours and procedures) and intensive margins (time spent with patients). The estimation results highlight the importance of flexibility in remuneration choices. Finally, the demand for moonlighting is an illegal activity whose profit depends on the market strategies adopted by competing firms. We propose a theoretical and experimental analysis of the effect of this particularity on the determinants of the demand for moonlighting. In particular, we focus on the potential effectiveness of a new instrument of repression: whistleblowing. We first show that the intensity of competition leads to Bertrand's curse: firms choose to escape but competition eliminates any benefit. We then study the conditions under which a market can implement collusive evasion, which allows for positive benefits from evasion. Whistleblowing is a favorable condition for the emergence of this strategy, and thus tends to encourage moonlighting. These results, confirmed by the observed behaviors, therefore militate against the introduction of this type of instrument. Taken together, these applications highlight the central role of the structure of interests held by the players involved: radically divergent, convergent but contradictory, or divergent but with a mechanism for reconciliation.

Illegal work has an astonishing capacity to cross centuries and borders. It is therefore difficult to discern its causes. We propose three lines of research. Theoretically, our objective is to develop models of the supply of black labor that take into account the official market. At the econometric level, the estimation of these models aims at removing some theoretical ambiguities and testing the validity of standard hypotheses. The first focus is on the determinants of black market participation and intensity. We introduce fixed costs of entering the black market and attest to their magnitude. Although they are lower than in the official market, they account for almost one-third of the potential income of non-participants. The second axis concerns taxation and enforcement. Our structural model endogenizes the subjective variables of probability of detection and fines. Our results reveal the importance of network effects and the absence of wage discrimination against women in the black market. The assumptions of perfect substitutability of hours and additive separability of the utility function are rejected. The third axis studies the impact of psychological and social norms on moonlighting. Our results show that younger people are more sensitive to the threat of ostracism. In contrast, women pay little attention to moral considerations. The absence of fraud among them results in the fear of financial sanctions. Finally, working hours, even in the absence of black market uncertainty, are imperfect substitutes.

Arbitration is an extrajudicial mode of conflict resolution which consists in resorting to a third person chosen by the parties to obtain a binding decision. This thesis is part of the body of economic work on arbitration by exploring the problem of conflict management from two different angles. On the one hand, starting from the observation that online commerce cannot be regulated by the traditional legal system, the first objective of this thesis is to analyze the effectiveness of a new electronic dispute resolution procedure: automated negotiation. On the other hand, considering that the recourse to arbitration cannot be explained only by a failure of negotiations, the second objective of this thesis is to base the existence of this procedure on its intrinsic qualities as a source of efficiency. This idea is analyzed by studying the role of arbitration as a substitute for full contracts. The theoretical analysis of automated bargaining shows that the "design" of this procedure has strategic implications that generate sub-efficient behavior on the part of individuals. The experimental analysis tends to qualify this result insofar as the conciliation effort of the parties depends significantly on the extent of the conflict between them. The role of arbitration as a substitute for full contracts is analyzed using a specific investment model. The efficiency of the arbitration procedure, as an incentive to invest, then depends on the arbitrator's behavior and the degree of specificity characterizing the relationship between the parties.

Holding a patent requires investing first in R&D to innovate, then in private protection to choose a mode of industrial protection and finally in renewal to keep the title in force. These investment opportunities give the innovator one or more real options: a growth option for the R&D investment, a deferred enforcement option related to the choice of a protection mode and an abandonment option related to the non-renewal of the patent. The deferred enforcement option is characterized by two antagonistic forces: a tendency to pre-empt (immediate patent filing) and the incentive to delay the filing date in order to develop an innovation with a high degree of sophistication (deferred decision). To justify the low propensity of firms to use the patent system as a mode of protection, this study assesses the incentive (in terms of efficiency) of innovators to use the patent system and its effectiveness in deterring entry. The efficiency of the patent system will be demonstrated by comparing renewal decisions when opportunities for profitability or defense of the patentee's rights are taken into account with those obtained in the reference framework. If the objective pursued is the profitability offered by the title, then innovators seem to have an incentive to protect their innovation(s) as soon as possible and to maintain their title(s) for a longer period. On the other hand, if their objective is anti-counterfeiting then they would tend to delay the filing date and shorten the life of the patent. The boundaries of entry possibilities allow one to isolate the system that most discourages entry. Thus, if in a static setting the patent is an effective entry deterrent, secrecy may become the preferred mode of protection in a dynamic setting.

Three dimensions of the technical progress hypothesis are explored. First, it is explained why, in the United States in particular, periods of strong growth in the skill premium have coincided with periods when the supply of skilled labor was lowest (1971-1979). In a model of endogenous growth with innovation, the bias toward individual ability increases intra-group inequality and reduces the incentive for ordinary-ability individuals to educate themselves. Growth based on technical progress biased in favour of individual capabilities thus amplifies the effects of the technological bias on wages through an insufficient response of the supply of skilled labour. Second, the analysis focuses on the cyclical nature of innovation and inequality in the long run. In a model where the choice of the sector in which researchers develop projects is endogenous, we show that innovators have an incentive to adopt technologies complementary to skilled or unskilled labor alternately. This alternation exerts a non-monotonic pressure on inequality, so a permanent bias is not robust in this framework. Third, the organizational dimension of technical progress is studied. The analysis developed focuses, on the one hand, on the determinants of organizational choices and on the relations between innovation, organization and market structure in a growth model. On the other hand, we explore the more microeconomic foundations of innovative organizational practices, i.e. the allocation of multiple productive tasks in an agency relationship, in order to highlight the interaction between multiskilling and incentive compensation. The main predictions of these two models are finally tested econometrically on French data from the 1997 survey "Organizational Change and Computerization".

The principle of voluntary contribution for the financing of a public good constitutes an appropriate alternative to the impossibility of resorting to a market mechanism by financing at marginal cost, because of the principles of non-rivalry and non-exclusion. This principle can be likened to a prisoner's dilemma game. The Nash equilibrium of such a game corresponds to the choice of a zero contribution to the financing of the public good on the part of the agents (free rider behavior), whereas the Pareto optimum assumes that all contribute their full endowment (complete cooperation). The satisfaction of individual interest is thus opposed to the satisfaction of collective interest. Experimental analyses of such a voluntary contribution game, however, reveal differences in behavior that lead to deviations between theoretical predictions and observed results, in the sense of over-contribution relative to equilibrium (Davis and Holt, 1993; Ledyard, 1995). Our study focuses on the importance of remuneration methods in the emergence of cooperation in voluntary contribution behaviors, with a focus on two directions. A first explanatory model of divergent contribution behavior introduces an endogenous asymmetry of individuals' resources in the form of reinvestment of the gains made during the game. In theory, while the asymmetry of resources reinforces the choice of free rider behavior, the introduction of the reinvestment mechanism increases the individual interest in cooperation. This model is the subject of an experiment whose results do not refute the theoretical predictions. A second model experimentally studies suboptimal overcontributions in order to decide between two hypotheses. The first hypothesis assumes that a lack of understanding of the rules of the game is at the origin of cooperation. The second hypothesis points to an aversion to financing due to the level of commitment required to finance the public good efficiently. The introduction of a level of efficient financing internal to the contribution space tests these hypotheses. The experimental evidence supports the second hypothesis.

The analysis of monetary policy has been greatly renewed in the last twenty years, thanks to the developments inspired by the articles of Barro and Gordon (1983 a and b). This work has made it possible, on the one hand, to propose an explanation of the inflationary phenomenon by demonstrating the dynamic incoherence of monetary policies and, on the other hand, to design institutional arrangements designed to control inflation. By influencing the incentives of the monetary policy maker, it is possible to encourage him to favour an anti-inflationary policy. The challenge then is to find arrangements that reduce uncertainty and dynamic inconsistency, but that leave some room for manoeuvre for the monetary authorities. The delegation of monetary policy to a conservative central banker is the institutional arrangement favored by many authors in the wake of the work of rogoff (1985). The purpose of this paper is to show that the dynamic incoherence is not completely resolved by this type of arrangement and that the content of the delegation should be modulated according to the context in which monetary responsibilities are exercised, on the one hand by integrating the budgetary authorities into the monetary policy game, and on the other hand by re-examining the role of rules. Simple independence with monetary leadership, coupled with monetary and/or budgetary rules, appears to be a very acceptable solution from the point of view of the credibility of monetary policy.

The theoretical analysis of negotiation amounts to reducing the variety of rules available to the different parties to reach an agreement. In this perspective, Rubinstein's (1982) model offers a resolution of a sequential, alternate-bid, finite-horizon bargaining game. By mobilizing the principle of 'backward induction', we identify a perfect subgame equilibrium in which the players reach equilibrium sharing in the first stage of the game. The ultimatum game, which assumes that the offer made is take-it-or-leave-it, is the simplest element of this model. The equilibrium sharing is then a very unequal distribution of payoffs among the players. First, the experimental study of the ultimatum game and the sequential bargaining games reveals an unparalleled preference for the equal distribution of payoffs, contrary to the predictions of the theory. The theoretical anomaly found supports the existence of reciprocal justice between negotiators assuming the existence of moral sentiments. The in-depth study of the offerer - responder relationship then highlights the multiplicity of individual motivations and the importance of <>. The plurality of moral feelings poses the problem of the internal coherence of the individual and requires their reduction. In a first approach, the reconciliation of experimental evidence and theoretical predictions amounts to incorporating non-monetary elements in the utility functions of players. Two approaches are then considered. The first one assumes that the aversion to inequality is the unifying motive of the individual's moral feelings. The second one prefers reciprocity understood as the attribution of intentions to others. The study of the relations existing between reciprocal justice and reciprocal envy is the object of an experimental protocol. In a second approach, the reduction of the individual's moral feelings is considered as the result of group interactions. Thus, reciprocal justice corresponds to the coordination of the players on a sharing assimilated to a social norm of behavior or preference. This result raises the problem of the robustness of reciprocal justice, which is then the subject of an experimental protocol.

In the face of the vast movement towards liberalization of telecommunications, the thesis studies the extent to which competition implies a more complex regulation of the sector, a complexity that is based on the need to develop a policy of interconnection to the public network. The first part, devoted to the process of market opening, highlights the need for specific regulation of the sector and underlines the essential role played by interconnection to the incumbent's network. On the basis of this observation, the second part of this paper, after stressing the importance of interconnection pricing with respect to the potential for competition, highlights the risks associated with poor interconnection pricing. The third part shows that interconnection is based on an ambiguous form of inter-firm cooperation. We develop a particular example of interconnection between mobile networks (national roaming). Based on a technical and economic analysis of this example and on the theory of cooperative games, this last part shows that the risks of abuse of the dominant position of the incumbent operator may gradually give way to risks of collusive behavior, the instrument of which could be the interconnection charge.

The imperfect appropriation of the benefits of r&d leads firms to underinvest in research. However, a diffusion of r&d results is favourable to a rapid technological progress. Horizontal ex-ante R&D cooperation agreements help to remedy this shortcoming. Nevertheless, the incentives to cheat within the agreement compromise the emergence and stability of R&D cooperation. In order to analyze more precisely these opportunistic behaviors, we propose two theoretical models. The first model highlights the negative influence of technological spillovers on the stability of cooperation. The second model shows that endogenous uncertainty allows inter-firm cooperation even when the horizon of interactions is finite, provided that firms value the future. The previous results are based on the fact that cooperation has been postulated. However, it seems necessary to question the construction of this cooperation in R&D by taking into account the implementation of collective knowledge (tacit knowledge). This work leads us to consider a learning process of an organizational nature and to propose a modelization of it. We show that this learning process has the property of ensuring flexibility of decision to the firms in terms of investment in r&d, and thus, allows to restore the incentives to innovate.