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In the labor economics literature, discrimination is often defined as occurring when identically productive workers, placed in the same working conditions, are assigned contracts involving, in particular, different hourly wage rates. This paper applies contract theory to explain how in some circumstances such differences take place, even if contract discrimination and productivity differences are strictly ruled out. It is assumed that worker types differ only in their consumption/leisure preferences and in their availability. A labor cost-minimizing firm offers a menu of labor contracts, and lets workers self-select. The model reveals external effects between types and the possibility of a paradoxical situation in which less demanding workers obtain a higher wage rate. A mixed employment regime always requires a minimum number (a quantum) of most demanding workers.

L’article presente les resultats d’une experience basee sur une variante du jeu « power-to-take » avec des implications concernant les modalites de prelevement de l’impot sur le revenu. L’etude compare le systeme d’impot a la source avec un systeme a posteriori, dans lequel l’impot est preleve bien apres le moment ou le contribuable a percu le revenu brut. Dans cette seconde situation, les contribuables peuvent developper un sentiment de propriete du revenu total, et ressentir un mecontentement plus important, a taux d’imposition identique. Nos resultats indiquent que l’insatisfaction associee a l’impot, mesuree par la sanction imposee sur l’agent qui preleve, est significativement plus importante dans le systeme a posteriori comparee au prelevement a la source. La communication vers le contribuable permet de reduire le taux de sanction, mais les participants n’exploitent pas vraiment cette opportunite.JEL Codes: C91, H26, D01.

This paper studies depositor behavior in a bank run experiment with partial deposit insurance. In the experiment, depositors face two forms of uncertainty regarding their deposit coverage in the event of a bank run: (i) “intrinsic” uncertainty related to the size of the deposit insurance fund, and (ii) “strategic” uncertainty, as the actual coverage depends on the number of depositors who run on the bank. We consider three scenarios that differ in the way the deposit insurance scheme reimburses depositors. The results show that intrinsic uncertainty on its own has a negligible effect on the number of bank runs. However, when combined, the two forms of uncertainty exert a significant impact on the propensity to withdraw and result in a large number of bank runs. Moreover, runs are more frequent when leaving funds in the bank is an increasingly costly strategy.

This paper introduces a new task to elicit individual aversion to deceiving, based on a modified version of the Deception Game as presented in Gneezy (2005). A multiple price list is used to determine the deception premium asked by an individual to switch from faithful to deceitful communication. The results show that, depending on payoffs, 71% of the subjects will switch at most once. Among them, 40% appear to be either “ethical” or “spiteful”. The other 60% respond to incentives in line with the cost of lying theory; they will forego faithful communication if the benefit from deceiving the other is large enough. Regression analysis shows that this deception premium is independent of the risk aversion and social preferences of the subject; it would thus capture an inner preference for behaving well.

This paper uses a controlled experiment to investigate how subjects exposed to competition in the workplace react in terms of well-being, and how this translates into productivity. The experiment was performed in Korea, a country with an interdependent culture, and France, a country with an independent culture. Exposure to the tournament slightly improves well-being in the Korean sample and decreases it in France. This different response is driven primarily by the opposite response of female subjects, with Korean women liking and French women disliking to compete. Finally, an improvement in well-being is associated with ex-post higher productivity in France, and this positive effect is most salient in the French male population; in Korea, a similar positive effect can be observed only in the female population.

This research note reports results of a survey on student satisfaction with distance education in Korea and France as implemented in May 2020 on 510 respondents. At that time, both countries closed the facilities of higher education institutions and imposed the extensive use of on-line education. A majority of French students express a preference for in-class teaching compared with on-line teaching, while preferences of the Korean students are more balanced. On average, Korean students express higher satisfaction with online teaching compared to French students. Women students also report higher satisfaction scores. The COVID-19 stress is negatively related to satisfaction with online teaching in Korea, but not in France.

This paper studies the impact of coordination frictions in financial markets on the cost of capital of real sector projects. In the model, a financial intermediary seeks to raise funds from many small investors, to finance a capital-intensive project. Investors face a coordination problem, as more capital invested in the project increases its chances of success. We employ a global games refinement to characterize the unique equilibrium of the game. The model features a non-monotonic relationship between the cost of capital and project profitability. There exists a ‘socially optimal’ price of capital that maximizes the probability of project success. However, fee-maximizing intermediaries set a return that is higher than the optimal rate. This higher cost of capital is the result of coordination frictions and suggests an inefficiency of the intermediation process. The model best characterizes project finance investments funded through bond markets and yields implications for their cost of capital.

This paper introduces a new instrument to elicit individual willingness to compete (WTC). Experimental data corroborate the standard result according to which the average WTC of men is higher than the average WTC of women. However, our WTC measure reveals significant within‐gender heterogeneity: 10% of women are extremely competitive, and 13% of men are extremely averse to competition. Gender differences in WTC persist after controlling for ability, self‐confidence, tolerance for risk, and the gender of the partner.

In some countries, including France, patients can choose between consulting a physician working in the regulated sector where, in general, fees are fully covered by health insurance (whether public, private or mixed), or a physician working in the unregulated sector, where a balance billing scheme operates. In the latter, fees might not be fully covered by health insurance, and patients must make out-of-pocket payments. The paper analyses the signalling properties of this mechanism in a context where patients are heterogenous with respect to their propensity to adhere to the prescribed treatment. The model reveals that a small extra fee allows to obtain a separating equilibrium in which only patients with a high propensity to adhere to the treatment will opt for the unregulated sector and benefit of a higher care effort on behalf of their physician. We also analyse the other equilibria of the game and comment on their welfare properties.

We introduce a dynamic public goods game, where an individual׳s investment in the public good at a given round provides benefits to other individuals in the next round, and the individual himself benefits from investments in the public good made by his current group members in the previous round. Subjects turn out to be more generous in this inter-temporal context than in a standard public goods experiment where contributions and transfers are exchanged at the same period. Furthermore, when known, benefits from the past investment are positively related to the individual׳s current investment in the public good.

This paper analyzes the strategic interaction between a crowdfunding platform specialized in medical projects and a set of potential investors. The problem is cast as a two-stage game. In the first stage, the platform chooses its participation fee and selects a project. In the second stage, investors decide whether to back the project or not. We consider a crowdfunding platform which runs all-or-nothing programs and transfers funds to the entrepreneur only if an investment target is reached. Moreover, we assume that some agents present a systematic positive bias driven by positive emotions about projects with high social impact, which is a major characteristic of medical projects. We frame the second-stage investor problem as a typical global game and solve it for the threshold equilibrium. The analysis reveals that crowdfunding finance might back financially inefficient projects, a result amplified by the existence of enthusiastic investors. We further show that the optimal fee charged by the platform is related to the frequency of overoptimistic agents, a result that might explain why platforms tend to over-emphasize the social role of their projects.

This paper brings experimental evidence on investors' behavior subject to an "illiquidity" constraint, where the success of a risky project depends on the participation of a minimum number of investors. The experiment is set up as a frameless coordination game that replicates the investment context. Results confirm the insidious nature of the illiquidity risk: as long as a first illiquidity default does not occur, investors do not seem able to fully internalize it. After several defaults, agents manage to coordinate on a default probability above which they refuse to participate to the project. This default probability is lower than the default probability of the first illiquidity default.

In a classical experiment, Niederle and Vesterlund (2007) used the dichotomous choice of individuals between a piece rate and a tournament payment scheme as an indication of their propensity to compete. This paper reports results from a two person interaction of a similar type to analyze whether the preference for competition is dependent on the gender of the partner. It introduces a Becker–DeGroot–Marschak mechanism to elicit individual willingness to compete (WTC), defined as the amount of money that makes an individual indifferent between the two compensation schemes. Even when controlling for risk aversion, past performance and overconfidence, the male WTC is e3.30 larger than the female WTC. The WTC instrument allows for a more precise analysis of the impact of the partner's gender on the taste for competition.

This paper presents experimental evidence on depositor behavior under partial deposit insurance schemes. In the experiment, the size of a deposit insurance fund cannot fully cover all deposits and the level of insurance depends on the number of depositors running on the bank. We show that this form of strategic uncertainty about deposit coverage exerts a significant impact on the propensity to withdraw, and results in a large frequency of bank runs. Runs are more likely when depositors have noisy information about the size of the insurance fund and as the maximum coverage increases, in line with a risk-dominant equilibrium selection mechanism. From a policy perspective, our results emphasize the limits of underfunded deposit insurance schemes in preventing systemic banking crises.

This paper analyzes the consequences of allowing for punishment in a real-effort pair production experiment. The behavior of the best performer in the team differs on whether he or she can impose a sanction on the less performing partner. When sanctions are not allowed, good performers reduce their effort in response to the advantageous difference in scores; when they can impose sanctions, their change in effort is no longer related to the difference in scores. To some extent, a sanction mechanism allows good performers to focus on their own performance. In the case of costless sanctions, not sanctioning a partner who under-performs, what we refer to as forgiveness, prompts the latter to improve his or her performance, but applying the sanction has a stronger push effect. Copyright © 2014 John Wiley & Sons, Ltd.

This paper analyzes how faculty members dynamically allocate their efforts between improving their research and teaching skills, taking into account the organizational structures and incentives implemented by academic institutions. The model builds on the assumption that organizational structures have an impact on the nature of spillover effects between teaching and research competencies. We analyze the dynamic equilibrium under unilateral and bilateral spillovers, using the no-spillover case as a benchmark. The bilateral spillover case is the most appealing as it achieves the highest overall performance; however, the nature of the equilibrium and the career paths can be quite different depending on the parameters of the problem such as the obsolescence of competencies or the strength of the spillover effect. This finding provides interesting insights on what could be the most productive configuration of a higher education institution.

This paper argues that in Euro-area economies, where the ECB cannot bail-out …nancially distressed governments, the …scal multiplier is adversely affected by the amount of public debt. A regression model on a panel of 26 EU countries over the period 1996-2011 shows that a 10 percentage point increase in the debt-to-GDP ratio is connected to a slowdown in annual growth rates of 0.28 percentage point. Furthermore, the e¤ectiveness of …scal spending is adversely affected by the amount of public debt; for a debt-to-GDP ratio above 150% the impact on growth of the …scal stimulus turns negative.

Connaissances en economie et reformes economiquesResultats d’une enquete menee au sein du reseau d’une grande ecole de commerceLes doutes sur le bien-fonde de l’economie de marche et la faiblesse des connaissances en economie sont deux faits averes en France. Dans cet article, nous utilisons les donnees d’une enquete menee en decembre 2009 via Internet au sein du reseau d’une grande ecole de commerce, pour etudier s’il existe un lien entre ces deux phenomenes. Un modele de regression permet d’expliquer l’opinion sur les reformes pro-marche, tout en prenant en compte le caractere endogene des connaissances en economie et les caracteristiques des repondants. Les resultats suggerent que les connaissances economiques influencent effectivement l’opinion sur les reformes pro-marche.JEL Code : A11, A14, A20, C83

This paper analyzes the effect of stricter sanctions against fraudulent disclosure in an economy where commercial lenders have only an imperfect information about the type of the firm they trade with. In the hybrid Bayesian equilibrium, some managers running fragile firms claim that their firm is solid only to benefit of better commercial credit terms. The default premium charged by the supplier over the normal cost can be interpreted here as an indirect bankruptcy cost. When the sanction gets heavier, both the default premium and the frequency of defaulting firms go up. Under given circumstances, these perverse effects might be offset by a decline in direct bankruptcy costs.

This paper investigates the production of research in business and economics. A scholar's reward is positively related to the quantity and quality of research. In turn, the quality of a paper depends on the scholar's ability to internalize new ideas and the overall quality of external research. The individual scholar is subject to a trade-off between writing more papers or reading in order to take in new ideas. In the Nash symmetric equilibrium, the quantity and quality of published papers are jointly determined. Under reasonable assumptions about the research production process, in equilibrium researchers write too many papers of too low a quality compared to the cooperative outcome. The model sheds some light on the effectiveness of various research policies currently under review by European policymakers.

ED EPS; National audience; Cet article étudie l'effet des transferts de fonds de migrants altruistes sur l'offre de travail des résidents,sous la forme d'un jeu à deux périodes en asymétrie d'information concernant la vraie situation économique des résidents. Le transfert optimal apparaît comme une fonction des salaires des deux agents. Lorsque le résident bénéficie d'une situation économique favorable, sous certaines conditions, il peut se comporter comme s'il était affecté par une situation mauvaise uniquement pour manipuler les anticipations des donateurs. Ces derniers, conscients de ce risque, réduisent le montant du transfert. De ce fait, à l'équilibre, le résident réellement touché par une conjoncture mauvaise se trouve pénalisé. Il peut alors mettre en oeuvre une stratégie de signalisation au prix d'une plus grande précarité.

This paper analyzes the production of fraudulent financial statements in a model featuring the main characteristics of the US corporate information market. Main players are managers, shareholders, auditors and the auditors’ public supervisor. It is shown that, in the overall equilibrium, not only managers at the head of bad firms, but also some of those running good firms may resort to dishonest reporting. The probability of cheating appears to be positively related to the frequency of good firms. Pushing too far the supervisor’s incentives to fight fraud might prompt more good firms’ managers to provide dishonest reports.

Many governments in developing countries contemplate the possibility of increasing the flexibility of their exchange rates despite having accumulated substantial dollar-denominated debt. Using a model of corporate dollar debt in which the future exchange rate is uncertain, this paper studies the financial risks that might arise as a consequence of increased exchange rate flexibility. Since a firm may default on its debt either because its dollar income is too low or because investors refuse to roll over its debt, the measure of the overall risk of default should take into account both factors, as well as their interaction. Solving the model for the no-default rational expectations equilibrium, we find that a small risk of insolvency may bring about a substantial risk of illiquidity.

This paper analyses the European central bank (ECB) monetary policy over the period 1999–2006, with a special emphasis on the recent years. The first part of the paper underlines the declared goals, decision variables and procedures, as can be inferred from various speeches of Jean-Claude Trichet, the President of the ECB. These statements are then weighted against the data, mainly through estimates of possible ECB interest rate rules. While in many respects the bank has performed reasonably well, several issues may be raised, mainly because the inflation objective has not been reached during the last period and monetary developments are not in line with economic stability. Policy recommendations follow, built on a renewed monetarist tradition: the reduction of the weight of real activity in the conduct of monetary policy, while further emphasising money via a money growth intermediate target.

This paper analyses data collected in 2012 and 2013 at the ESSEC Business School from Kallystée, a proprietary mass-attendance business game. Company boards are simulated by groups of five students selected at random. We manipulate the gender composition of the management teams to allow for all possible gender combinations. We show that all-men and mixed teams with four women perform significantly better than all-women teams. However, when controlling for the average tolerance to risk of the teams, the performance advantage of all-men teams vanishes, while the “residual” economic performance of mixed-gender teams with a majority of women is still positive and strong. Further analysis of “actual” risk-taking behavior shows that in these mixed-gender teams a “risk shift” mechanism is at play, as they take risks beyond what their total tolerance to risk as a group would suggest.

The paper reports results from an Ultimatum Game experiment with asymmetric information where Proposers can send to Responders misleading information about their endowment. We allow for all possible gender combinations in the Proposer-Responder pairs. Proposer messages that underestimate the actual amount are quite widespread. The frequency of lying is slightly higher in mixed groups. Conditional on lying, men tend to state bigger lies than women. On the other hand, women tend to tell smaller lies when paired with men, than when paired with women. In general, women present higher acceptance rates than men.

This paper analyses data collected in 2012 and 2013 at the ESSEC Business School from Kallystee, a proprietary mass-attendance business game. Company boards are simulated by groups of five students selected at random. We manipulate the gender composition of the management teams to allow for all possible gender combinations. We show that all-men and mixed teams with four women perform significantly better than all-women teams. However, when controlling for the average tolerance to risk of the teams, the performance advantage of all-men teams vanishes, while the “residual” economic performance of mixed-gender teams with a majority of women is still positive and strong. Further analysis of “actual” risk-taking behavior shows that in these mixed-gender teams a “risk shift” mechanism is at play, as they take risks beyond what their total tolerance to risk as a group would suggest.

After the fall of the Berlin Wall, European governments adopted a hands‐off policy towards the defence industrial base, in an attempt to increase the sector’s efficiency and reactivity. In this context, one topical issue is how to motivate defence firms to apply for private rather than public finance. Since banks have no prior experience with European defence firms, a problem of asymmetric information may block this transition. The problem is analysed within the framework of a game between defence firms and banks. It is shown that the Bayesian Equilibrium might correspond to a situation where low‐risk firms prefer the state‐financed scheme; yet, in a perfect information set‐up, the same firms would apply for bank credit. In order to facilitate the transition to private finance, the government might decide to subsidize investors who agree on financing defence firms; the state aid should be made available during a transitory learning period. *This research has benefited from the financial support of the Obs...

A la fin des annees 90, de nombreuses economies en voie de developpement presentaient un important endettement en dollars. Dans ce contexte, l’adoption d’un regime de flottement pur constitue-t-il un choix economiquement raisonnable? Nous proposons un modele dans lequel des generations successives de preteurs internationaux doivent decider s’ils souscrivent ou non aux emissions en dollars d’une firme du secteur prive. En regime de changes flexibles, les fluctuations du cours de la monnaie nationale influencent la valeur des dettes en dollars et induisent un risque d’insolvabilite. Nous montrons alors que ce risque d’insolvabilite, d’ordre de grandeur negligeable a priori, induit en revanche un tres fort risque d’illiquidite. Pour eviter ce risque, une firme produisant un bien destine au seul marche domestique devrait renoncer a quasiment tout financement en monnaie internationale.

This paper analyzes the production of fundamental research as a coordination game played by scholars. In the model, scholars decide to adopt a new idea only if they believe that a critical mass of peers is following a similar research strategy. If researchers observe only a noisy idiosyncratic signal of the true scientifi…c potential of a new idea, we show that the game presents a single threshold equilibrium. In this environment, fundamental research proceeds with large structural breaks followed by long periods of time in which new ideas are unsuccessful. The likelihood of a new idea emerging depends on various parameters, including the rewards of working in the old paradigm, the critical mass of researchers required to create a new school of thought and scholars’ ability to properly assess the scientifi…c value of new ideas.

During the US Internet bubble (1995-2001), several top executives dismissed both the law and ethical norms transferring large chunks of company wealth into their own hands. This paper investigates the key economic factors that brought about the proliferation of dishonest managerial behaviour, focussing on the weak internal control, perverse incentives related to managers' compensation schemes and conflicts of interest in the banking and auditing sectors. In order to prevent further abuses, the US administration imposed several regulatory changes, mainly through the Sarbanes- Oxley Act of 2002; we argue why some of its provisions might be taken one step further.

This paper presents estimates of the European Central Bank (ECB)'s interest rate rule using monthly data for the period of the Willem F. Duisenberg presidency (from January 1999 to October 2003). Our results show that, like the US Federal Reserve, the ECB appears to be concerned with fluctuations in economic activity. It increases its short-term interest rate if inflation deviates from target, this reaction being stronger if based on future inflation and weaker if based on current inflation. The seemingly soft response to current inflation derives from a concern for exchange rate stability and may reflect the Bank's forecast of future inflation. The ECB also appears to smooth its interventions in the money market.

Sometimes homogenous goods trade at different prices and some other times different qualities trade at the same price. This paper analyses such deviations from the “Law of One Quality–One Price” within the framework of an equilibrium search model. On the supply side, firms decide on both the price and the complexity index of a unit good. On the demand side, consumers search for the best offer in a sequential way. By assumption, only some “expert” consumers need the new feature incorporated into the complex item. In equilibrium, consumers’ searching strategy and firms’ price–quality optimal choice are mutually consistent. Non-degenerated equilibrium price and/or quality distributions emerge, in keeping with the proportion of expert consumers in total consumer population.

According to a well-established economic principle, any public debt that does not exceed the discounted stream of future primary surpluses should find buyers. This paper argues why this principle may not hold if the government has only imperfect control over its net income flow. A small risk of unsustainability appears to be at the origin of a much larger risk of illiquidity. Solving the model for the rational expectations equilibrium, we find that the maximum debt level that investors are willing to hold may be much lower than the commonly used sustainable level.

Euro candidates are expected to maintain the value of their currency within the fluctuation band of the new exchange rate mechanism for at least two years. This paper highlights some unpleasant macroeconomic effects that could occur during this interval. The problem is cast as a two-stage sequential game between private agents and the government of the applicant country. The policy-maker decides whether to devaluate the domestic currency or not at two distinct dates; it makes a last choice just before accession to the monetary union. Under an assumption of incomplete information of private agents about the government's priorities on inflation and economic activity, the game presents a hybrid perfect Bayesian equilibrium. In the pooling configuration, an initial policy of zero devaluation does not signal the final devaluation decision. As private agents cannot completely rule out the risk of a ‘last devaluation’, a premium adds to interest rates and entails a systematic output loss.

In the late eighties, many developing countries followed the example of the most advanced countries and opened their capital account (K.A.) in an attempt to reap new gains from increased integration with the world economy. Currently, after the wave of financial and currency crises that hurt the global economy over the last decade, enthusiasm about K.A. liberalization has greatly faded. First, the relationship between development and capital account liberalization did not come out to be as solid as initially expected; second, the greater capital mobility has brought about new forms of financial instability. This paper points to some risks that might be associated with undifferentiated deregulation of international movements of capital in connection with developing economies. It argues in favor of proper sequencing: liberalization should proceed in parallel with progress when it comes to macroeconomic stability, building market competition and the creation of a sound, internal financial system. A separate section analyzes this issue in the special context of transition economies.

To various degrees, Central and Eastern European countries increased their participation to the world economy over the last ten years. In particular, they accepted the challenge of trade openness and attracted significant foreign direct investment. This paper assesses the impact of these major changes on output growth in this region. Results of a panel data analysis suggest that increased EU integration and openness as well as reduced import duties were favourable to development. There is also evidence that increased FDI inflows may be associated with better output performances. Comparative Economic Studies (2002) 44, 119–136; doi:10.1057/ces.2002.22

The possibility of facing dishonest local managers is an important factor explaining foreigners’ hesitations about investing in developing countries. The first part of the paper analyses the optimal decision rule of a manager who is able to transfer into his own hands a part of the output of the firm. It is shown that in a two-period framework with incomplete information about the nature of the manager, a rational expectations equilibrium exists where managers’ behaviour and investors’ expectations are mutually consistent. In particular, some young managers may aim at building a reputation of an honest person, then behave dishonestly when getting old. The global performance of an economy hosting a large number of managers is investigated in the second part of the paper, where analysis is cast in an overlapping generation framework. The frequency of dishonest managers, development prospects and global profitability appear to depend on the duration of the relationship between investors and managers.

In the aftermath of the Second World War, European citizens shared the belief according to which an economically integrated Europe would prevent European peoples from fighting each other again. If this argument still remains valid, many younger European citizens, who did not go through the war atrocity, are supporting the European project insofar as it associated to an image of modernity, openness, and, ultimately, higher living standards.

Experience shows that developing countries or regions that vary little with respect to their fundamentals sometimes follow different growth paths. Such puzzling facts may occur if less informed international investors imitate those who are well informed about profit opportunities instead of acquiring the relevant information themselves. This paper analyses how the type of mimetic behaviour influences the development pattern of an economy where the lack of infrastructure is the main constraint on development. Possible outcomes may be stationary growth, divergent growth or cycles in development.

Voucher privatization implies a significant wealth transfer from state to private agents who, in turn, would increase consumption. This paper investigates the consequences of this wealth effect on the macroeconomic equilibrium in a high unemployment economy. The model builds on a two-stage sequential game between the government and private agents. We verify the existence of a pooling equilibrium in which private agents cannot guess whether a policy of fast privatization will be continued in the future or not. This configuration presents an endogenous probability of privatization slowdown; as a consequence, the wealth effect is moderated and the genuine fast privatizer government bears an “undue” credibility cost in terms of employment

This paper develops two stylised models of the transition economy that challenge, to some extent, the conventional approach to policy reforms. In the first model, the absence of market-oriented institutions is responsible for the occurrence of a non-cooperative equilibrium, where the amount of public services provided by the state is too low, which, in turn, adversely affects the global performance of the economy. In the second model, a benevolent government will choose a taxation level that pushes too many firms out of the market; hence global supply falls below its optimal level. In both models, disruptions specific to transitional systems lead to abnormal responses to standard fiscal policy.

This paper aims to provide a simple trade union model which highlights some of the distinctive institutional features of French unionism. The model focuses on the determinants of militancy and membership in a frictionless economy. It brings into the picture three types of agents and their specific behaviour: firms accept to pay a premium in order to avoid strikes, individuals participate in the union in order to maximise their expected income and union leadership seeks to maximise his/her net personal gain. By adapting militancy—broadly defined as hard stance during the annual wage bargaining—the union leader may achieve a unionisation rate consistent with his/her own objectives. It is shown that a non-Walrasian labour market equilibrium exists wherein real wages, employment, union size and militancy are jointly determined. In comparative statics, the model predicts a negative relationship between militancy and membership; recent evolutions of the main French union confederations tend to support this conclusion.

International audience; Gladiatorial combat was in reality a lot less lethal than it is depicted in the cinema. This short paper highlights how cooperative strategies could have prevailed in the arenas, which is generally what happened during the Games. Cooperation in the arena corresponded to a situation of the professionalization of gladiators, who been trained in gladiatorial schools. This case provides an analogy of the conditions under which cooperation occurs in a context of competition between rival companies.