Publications

Résumé For some smooth special case of generalized $\varphi-$divergences as well as of new divergences (called scaled shift divergences), we derive approximations of the omnipresent (weighted) $\ell_{1}-$distance and (weighted) $\ell_{1}-$norm.
Mots clés Divergence Kullback-Leibler, Divergence analysis, $\ell1-$distance/norm, Generalized $\varphi-$divergences
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Résumé We propose the stepwise Cauchy combination test (StepC), a new procedure for multiple testing with dependent test statistics and sparse signals. Unlike the global version, StepC pinpoints which p-values drive rejections, while maintaining strong familywise error control. It is less conservative under dependence and more powerful than conventional multiple testing corrections. In simulations and in applications to drift burst detection and testing for nonzero alphas, StepC consistently boosts power and yields more meaningful rejections, making it a practical alternative for large-scale financial datasets.
Mots clés Nonasymptotic approximation, Sequential rejection, Multiple hypothesis testing, Familywise error, Dependence
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Résumé This paper revisits the question of whether fixed and mobile Internet expenditures are substitutable or complementary. We estimate a demand system using French household expenditure data to compute price elasticities for different categories of goods. The results indicate that fixed and mobile Internet expenditures are complementary in France. This complementarity effect increases with income level. We then develop a simple theoretical model showing that depending on the characteristics of fixed and mobile data tariffs, fixed and mobile Internet expenditures can exhibit non-substitutability or even complementarity.
Mots clés QUAIDS demand system, Household behavior, Internet expenditure
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Résumé We use an overlapping generations model with physical and human capital, and two reproductive periods to explore how fertility decisions may differ in response to economic incentives in early and late adulthood. In particular, we analyze the interplay between fertility choices—related to career opportunities—and wages, and investigate the role played by work experience and investment in both types of capital. We show that young adults postpone parenthood above a certain wage threshold and that late fertility increases with work experience. The long run trend is either to converge to a low productivity equilibrium, involving high early fertility, investment in physical capital and relatively low income, or to a high productivity equilibrium, where households postpone parenthood to invest in their human capital and work experience, with higher late fertility and higher levels of income. A convergence to the latter state would explain the postponement of parenthood and the mitigation or slight reversal of fertility decrease in some European countries in recent decades.
Mots clés Fertility, Overlapping generations, Work experience, Postponement
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Résumé We consider public goods games with heterogeneous players interacting on a network and investigate how shocks to players' characteristics and changes in interaction patterns influence individual and total contributions. We introduce a linear system associated to the initial game, in which heterogeneity in players' characteristics is removed and interactions between players are reversed, and show that what matters in determining the effects of a shock on contributions is the sign of the coordinates of its unconstrained solution. When players are identical, we demonstrate that positive shocks on active players increase contributions, while positive shocks on strictly inactive players decrease them, contrary to intuition. We also identify a subset of players, called neutral players, who exert no influence on total contributions. Furthermore, we provide precise formulas for the change in total contributions following various types of shocks, and provide conditions to determine whether the shock will have positive or negative consequences on contributions. We show that these conditions always rely on the sign of the associated problem's unconstrained solution coordinates of the players impacted by the shock.
Mots clés Comparative Statics, Heterogeneous Players, Public goods
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Résumé This paper studies the dynamic relationship between economic growth, pollution, and government intervention. To do so, we develop a model that links pollution to the economy’s productive capacity, thereby capturing the feedback loops between economic activity, environmental degradation, and fiscal policy intervention. The model incorporates a pollution-sensitive damage function, taxes, and government spending while analyzing economic growth under different levels of government intervention. Therefore, the main paper’s contributions reveal that economies can achieve favorable outcomes with low or moderate government intervention, and that our results underscore the vital role of pollution mitigation policy in dynamically balancing economic growth with environmental sustainability.
Mots clés Public debt, Fiscal policy, Pollution, Economic Growth
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Résumé This paper tests experimentally how preferences for redistribution of members of the general public depend on how money is earned. An experiment was designed to form of “microparticipatory-democracy”where redistribution from winners to losers is decided through a sequential strategy-proof majority voting procedure. Based on five distributive justice theories, we elicit people’s preferences for redistribution when their earnings come from four factors: effort, social circumstances, brute luck, and option luck. In the aggregate, our results show that a relative majority of people agree with Dworkin’s cut, namely, to compensate for social circumstances and brute luck but not effort and option luck. Participants with bad outcomes are more likely to engage in a self-serving vote, but on average, the dominant concern in voting remains people’s fairness view. The knowledge of the distribution of earnings and petition for equality of opportunity make participants vote more in favor of redistribution.
Mots clés Responsibility, Equality of opportunity, Micro participatory-democracy, Social justice, Experiment
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Résumé This paper tests experimentally how preferences for redistribution of members of the general public depend on how money is earned. An experiment was designed to form of “microparticipatory-democracy”where redistribution from winners to losers is decided through a sequential strategy-proof majority voting procedure. Based on five distributive justice theories, we elicit people’s preferences for redistribution when their earnings come from four factors: effort, social circumstances, brute luck, and option luck. In the aggregate, our results show that a relative majority of people agree with Dworkin’s cut, namely, to compensate for social circumstances and brute luck but not effort and option luck. Participants with bad outcomes are more likely to engage in a self-serving vote, but on average, the dominant concern in voting remains people’s fairness view. The knowledge of the distribution of earnings and petition for equality of opportunity make participants vote more in favor of redistribution.
Mots clés Experiment, Responsibility, Equality of opportunity, Micro participatory-democracy, Social justice
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Résumé There is a significant gap in turnout between young people and older voters. The failure to instill a voting habit at an early age may have long term consequences in terms of future political participation as well as on other civic behaviors. Using a pre-registered online experiment with 3790 subjects, we implemented behavioral interventions aiming to stimulate youth turnout in the 2022 French presidential election. We rely on an innovative incentive scheme to measure their consequences on (self-reported) actual voting behavior. We also provide evidence on the effect of one behavioral intervention on youth turnout in a less salient election, the French legislative election that took place two months after the Presidential one. The results from the two experiments show the absence of any differences in turnout between the baseline and the treatment conditions. We investigate several mechanisms that can explain our results.
Mots clés Youth turnout, Behavioral nudges, Field experiment, Behavioral public policy
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Résumé Since the COVID-19 pandemic, there is growing evidence that the social epidemiological context may play a crucial role in the adoption of health protective behaviours in response to emerging infectious diseases. Yet, our understanding of how and why these behaviours are influenced by the epidemiological forces remains relatively limited. This repeated, cross-sectional investigation examines the extent to which the association between the socio-epidemiological context and protective behaviour was mediated by a series of common social cognitive factors from leading models of health behaviour during the COVID-19 epidemic in France. Representative samples of the French population completed an online, self-report survey at seventeen intervals (March-November 2020), with approximately 2000 participants in each survey wave. Results indicate that both contextual and social cognitive variables largely drove the adoption of protective behaviours over time. However, social cognitive variables only partially mediated the effect of the epidemiological context on protective behaviour (physical distancing and hygiene measures), suggesting that unknown factors may be operating in addition to those commonly used in these models. These findings highlight the need for future research to consider the epidemiological context, and further possible mediating variables, when modelling determinants of social cognitions and preventive behaviour, and above all, to broaden its focus to include neglected underlying psychological mechanisms involved in the behavioural response to epidemics.
Mots clés Epidemic context, France, Protective behaviours, COVID-19, Social cognitive factors, Epidemiological context
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Résumé Cancer accounts for approximately one-third of deaths in developed countries. Preventing cancer, notably by detecting new cases early, is thus crucial. In the European Union (EU), screening rates have been recommended for several types of cancer; however, most EU countries are still not meeting them. Determining how we can improve people’s adherence to screening is necessary. This study aimed to explore the characteristics of women associated with being up-to-date on mammograms or Pap smears; notably, we wanted to determine the extent to which women’s attitudes towards risk play a role in their adherence to screening. The sample comprised 1411 women who responded to a telephone survey. The survey data, including sociodemographic characteristics, health information, attitudes towards the future, and attitudes towards risk, collected via the Domain-Specific Risk-Taking (DOSPERT) scale, were supplemented by medico-administrative data. The factors associated with undergoing either a mammogram or a Pap smear in a timely manner were similar. Two favourable factors were found: the number of children and a high level of education. In contrast, being older or having a higher DOSPERT score for risk-taking appeared to be negatively associated with timely screening. The fact that women’s attitudes towards risk seem to have a strong impact on their adherence to medical recommendations is a finding that should be considered (e.g. by health professionals or in prevention campaigns) regarding increasing women’s awareness of the importance of regular cancer screening.
Mots clés Prevention, Screening test, Cancer screening, Risk-taking behavior, Vaginal smears, Telephone, Mammography, Health personnel, European union, Educational status, Developed countries, Child, Attitude, Cancer
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Résumé We analyze earnings responses to six large payroll tax and income tax reforms in France. Our findings indicate full pass-through to workers when there is a strong and transparent link between contributions and expected benefits. In contrast, employer payroll taxes with no tax-benefit linkage exhibit limited pass-through to workers, while income tax nominally borne by employees show nearly full passthrough. Together with a meta-analysis of the literature, we interpret these results as empirical support for the long-standing hypothesis that tax-benefit linkage matters for the incidence of payroll taxes. In the absence of such linkage, our findings suggest that the individual-level incidence of payroll taxes aligns with their statutory incidence.
Mots clés Statutory incidence, Tax-Benefit Linkage, Payroll Tax, Tax Incidence
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Résumé Abstract We present the discovery of 11 new transiting brown dwarfs (BDs) and low-mass M dwarfs from NASA’s Transiting Exoplanet Survey Satellite (TESS) mission: TOI-2844, TOI-3122, TOI-3577, TOI-3755, TOI-4462, TOI-4635, TOI-4737, TOI-4759, TOI-5240, TOI-5467, and TOI-5882. They consist of five BD companions and six very-low-mass stellar companions ranging in mass from 25 M J to 128 M J . We used a combination of photometric time-series, spectroscopic, and high-resolution imaging follow-up as a part of the TESS Follow-up Observing Program (or TFOP) to characterize each system. With over 50 transiting BDs confirmed, we now have a large enough sample to directly test different formation and evolutionary scenarios. We provide a renewed perspective on the transiting “brown dwarf desert” and its role in differentiating between planetary and stellar formation mechanisms. Our analysis of the eccentricity distribution for the transiting BD sample does not support previous claims of a transition between planetary and stellar formation at ∼42 M J . We also contribute a first look into the metallicity distribution of transiting companions in the range 7–150 M J , showing that this does not support a ∼42 M J transition too. Finally, we also detect a significant lithium absorption feature in one of the BD hosts (TOI-5882). However, we determine that the host star is likely old based on rotation, kinematic, and photometric mdeasurements. We therefore claim that TOI-5882 may be a candidate for planetary engulfment.
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Résumé Abstract We present the discovery of 11 new transiting brown dwarfs (BDs) and low-mass M dwarfs from NASA’s Transiting Exoplanet Survey Satellite (TESS) mission: TOI-2844, TOI-3122, TOI-3577, TOI-3755, TOI-4462, TOI-4635, TOI-4737, TOI-4759, TOI-5240, TOI-5467, and TOI-5882. They consist of five BD companions and six very-low-mass stellar companions ranging in mass from 25 M J to 128 M J . We used a combination of photometric time-series, spectroscopic, and high-resolution imaging follow-up as a part of the TESS Follow-up Observing Program (or TFOP) to characterize each system. With over 50 transiting BDs confirmed, we now have a large enough sample to directly test different formation and evolutionary scenarios. We provide a renewed perspective on the transiting “brown dwarf desert” and its role in differentiating between planetary and stellar formation mechanisms. Our analysis of the eccentricity distribution for the transiting BD sample does not support previous claims of a transition between planetary and stellar formation at ∼42 M J . We also contribute a first look into the metallicity distribution of transiting companions in the range 7–150 M J , showing that this does not support a ∼42 M J transition too. Finally, we also detect a significant lithium absorption feature in one of the BD hosts (TOI-5882). However, we determine that the host star is likely old based on rotation, kinematic, and photometric mdeasurements. We therefore claim that TOI-5882 may be a candidate for planetary engulfment.
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Résumé Comment les compétences psychosociales (CSP) peuvent-elles offrir un cadre pertinent pour intégrer l’empathie dans les processus pédagogiques et évaluatifs des études de santé ? Les CSP sont définies par l’Organisation mondiale de la santé et Santé publique France comme un ensemble cohérent et interrelié de capacités psychologiques. Elles permettent à une personne de maintenir un état de bien-être psychique et d’adopter des comportements adaptés et positifs. En nous appuyant sur les dispositifs évaluatifs déjà en place dans les études de santé, nous proposons des pistes pour inscrire durablement l’empathie, à la fois dans les référentiels de compétences et dans les modalités d’évaluation tout au long des cursus en santé.
Mots clés Health education, Social competence, Self-evaluation, Psychological adaptation, Professional competence, Medical education, Empathy, Communication, Enseignement médical, Empathie, Éducation à la santé, Compétence sociale, Compétence professionnelle, Communication, Autoévaluation, Adaptation psychologique
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Résumé http://www.tei-c.org/ns/1.0">Recent advances in artificial intelligence (AI) have made it possible to detect neurodegenerative diseases (NDDs) earlier, potentially improving patient outcomes. However, AI-based detection tools remain underutilized. We studied individual valuation for early diagnosis tests for NDDs. We conducted a discrete choice experiment with a representative sample of the French adult population (N = 1017). Participants were asked to choose between early diagnosis tests that differed in terms of: (1) type of test (saliva vs. AI-based tests analysing electronic health records); (2) identity of the person communicating the test results; (3) sensitivity; (4) specificity; and (5) price. We calculated the weights in the decision for each attribute and examined how socio-demographic characteristics influenced them. Respondents revealed a reduced utility value when AI-based testing was involved (valuated at an average of €36.08, CI [€22.13; €50.89]) and when results were communicated by a private company (€95.15, CI [€82.01; €109.82]). We interpret these figures as the shadow price that the public attaches to medical data privacy. Beyond monetization, our representative sample of the French population appears reluctant to adopt AI-powered screening, particularly when performed on large sets of personal data. However, they would be more supportive when medical expertise is associated with the tests.
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Résumé Honest and dishonest behaviors may both diffuse among the members of an organization. Knowing which of the two spreads faster is important because it impacts the extent to which managers will need to resort to other, potentially more costly solutions to curb dishonest behavior. Assessing empirically which of honest behavior or dishonest behavior spreads faster is challenging because this requires field measurements of social relationships and dishonest behavior of individual members, which poses both measurement and inference problems. We examine an original fine-grained data set from a large company that allows for identifying agents likely to be dishonest and interactions among employees while offering a natural experiment that circumvents the inference problems associated with identifying peer-to-peer diffusion. We find (1) that dishonest behavior diffuses, whereas honest behavior does not; (2) that diffusion likely operates through spreading information about opportunities for collusion; and (3) that policies that screen on dishonesty at hiring may be efficient to curb dishonest behavior in environments with high turnover. This paper was accepted by Lamar Pierce, organizations. Funding: R. Ferrali acknowledges support from the Mamdouha S. Bobst Center for Peace and Justice [Grant 2016-12-Bobst], the French National Research Agency [Grant ANR-17-EURE-0020], and Aix-Marseille University—A*MIDEX [Excellence Initiative]. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2023.01981 .
Mots clés Dishonesty, Natural experiment, Organization Behavior, Network analysis
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Résumé In this article, we propose a theory that explains how Free/Libre Open Software (FLOSS) projects work and how companies rely on these FLOSS projects to develop their commercial offers, what we refer to as their "opensource" business model(s). This article builds on and refines the studies of the FLOSS organization by connecting two interrelated aspects: 1) how this organization evolves over time, in order to 2) better understand the value that users create and capture at each moment of a FLOSS project, with a particular focus on open-source companies, which are specific users who do business based on the software created by the FLOSS project. We describe these models and show that the open-source business models of companies are based on contributing to FLOSS projects in order to be able to provide "3A" services (assurance, adaptation, and assistance or support for use) that are complementary to the access to the software. Providing these services requires participation in the FLOSS project, which provides the project with the resources to operate. This work can help the software engineering community by showing how FLOSS evaluation tools can be improved by taking into account the maturity of the solution, the strategic need of the target user, and the complementary open-source offers that exist.
Mots clés FLOSS, Open-source, Business models, Value network, Software-flow, Strategy, FLOSS Open-source Business models Value network Software-flow Strategy, FLOSS
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Résumé 101 real couples participated in a controlled experimental risk-taking task involving variations in household and individual income risks, while controlling for ex-ante income inequality. Our design disentangles the effects of household risk, intra-household risk inequality, and ex-post payoff inequality. We find that most couples (about 79%) pooled their risk at the household level when risks were borne symmetrically, but a significant proportion of couples (about 36%) failed to do so when individual risks were borne asymmetrically. Additionally, within the scope of the control variables we have utilized, we find that intra-household risk inequality has a larger impact on non-married couples compared to married ones. These results remain robust when the analysis is limited to couples in which both spouses are risk-averse. Lastly, we find that preferences for household efficiency are significantly correlated across both certain and risky situations. However, couples consisting of two income-maximizing spouses do not show greater aversion to risk inequality compared to couples with other compositions.
Mots clés Experiment, Household risk taking, Inequality
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