Publications

Résumé This study investigates how El Niño–Southern Oscillation (ENSO) climate patterns affect global economic conditions. Prior research suggests that ENSO phases, particularly El Niño, influence economic outcomes, but with limited consensus on their broader macroeconomic impacts. Using a novel monthly dataset from 20 economies, covering 80% of global output from 1999 to 2022, we employ a global augmented vector autoregression with local projections (GAVARLP) model. The empirical findings suggest that El Niño boosts output with minimal inflationary effects, reducing global economic policy uncertainty, while La Niña raises food inflation, which can amplify aggregate inflation as a ‘‘second-round’’ effect, amplifying uncertainty. These findings shed light on the transmission channels of climate shocks and highlight the significant role of ENSO in shaping global economic conditions, emphasizing why climate shocks should be a concern for policy markers.
Mots clés Climate ENSO, Oil prices, Food prices, Global macroeconometric modeling, Economic policy uncertainty
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Résumé Cet article analyse les difficultés anticipées par les entreprises en France lorsqu'elles envisagent de recruter. En croisant les données des enquêtes Besoins en main-d'oeuvre de 2018 et 2019 avec les données d'entreprise FARE et DADS, nous étudions comment les difficultés de recrutement se déclinent selon le secteur, la localisation et la taille de l'établissement et selon les caractéristiques du bassin d'emploi. L'ensemble de ces caractéristiques explique environ 6 % de la variance totale observée des difficultés de recrutement anticipées et jusqu'à 14 % si l'on y ajoute les difficultés de recrutement éventuellement anticipées l'année précédente. L'essentiel des difficultés anticipées résulte ainsi de facteurs non observés dans les données utilisées dans cet article, en lien potentiellement avec les caractéristiques internes propres à chaque établissement, comme la qualité du management et les spécificités des processus de recrutement.
Mots clés Company data, Probit, Recruitment difficulties, Probit, Données d&#039, entreprises, Difficultés de recrutement
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Résumé This paper studies the dynamics of information diffusion within networks, encompassing both general and targeted dissemination. We first characterize the theoretical foundations of diffusion centrality. Next, we introduce two extensions of diffusion centrality: targeting centrality and reachability, that we believe to better capture situations involving targeted requests. We derive general explicit formulas for the computation of these novel centrality measures.
Mots clés Targeting, Political intermediation, Centrality, Diffusion
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Résumé Background The γ-metric value is generally used as the importance score of a feature (or a set of features) in a clas- sification context. This study aimed to go further by creating a new methodology for multivariate feature selection for classification, whereby the γ-metric is associated with a specific search direction (and therefore a specific stopping criterion). As three search directions are used, we effectively created three distinct methods. MethodsWe assessed the performance of our new methodology through a simulation study, comparing them against more conventional methods. Classification performance indicators, number of selected features, stability and execution time were used to evaluate the performance of the methods. We also evaluated how well the proposed methodology selected relevant features for the detection of atrial fibrillation, which is a cardiac arrhythmia. ResultsWe found that in the simulation study as well as the detection of AF task, our methods were able to select informative features and maintain a good level of predictive performance; however in a case of strong correlation and large datasets, the γ-metric based methods were less efficient to exclude non-informative features. Conclusions Results highlighted a good combination of both the forward search direction and the γ-metric as an evaluation function. However, using the backward search direction, the feature selection algorithm could fall into a local optima and can be improved.
Mots clés Γ-metric, Feature selection, Classification, Atrial fibrillation
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Résumé In this paper, we show that a decomposition of changes in inequality, with the mean log deviation index, can be obtained directly from the Oaxaca-Blinder decompositions of changes in means of incomes and log-incomes. It allows practitioners to conduct simultaneously empirical analyses to explain which factors account for changes in means and in inequality indices between two distributions with strictly positive values.
Mots clés Oaxaca-Blinder decomposition, MLD index, Inequality, Inequality Oaxaca-Blinder decomposition MLD index
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Résumé Within the International Health Regulations framework, the French High Council for Public Health was mandated in 2022 by health authorities to establish a list of priority infectious diseases for public health, surveillance and research in mainland and overseas France. Aim Our objective was to establish this list. Methods A multi-criteria decision analysis was used, as recommended by the European Centre for Disease Prevention and Control. A list of 95 entities (infectious diseases or groups of these, including the World Health Organization (WHO)-labelled ‘Disease X’) was established by 17 infectious disease experts. Ten criteria were defined to score entities: incidence rate, case fatality rate, potential for emergence and spread, impact on the individual, on society, on socially vulnerable groups, on the healthcare system, and need for new preventive tools, new curative therapies, and surveillance. Each criterion was assigned a relative weight by 77 multidisciplinary experts. For each entity, 98 physicians from various specialties rated each criterion against the entity, using a four-class Likert-type scale; the ratings were converted into numeric values with a nonlinear scale and respectively weighted to calculate the entity score. Results Fifteen entities were ranked as high-priorities, including Disease X and 14 known pathologies (e.g. haemorrhagic fevers, various respiratory viral infections, arboviral infections, multidrug-resistant bacterial infections, invasive meningococcal and pneumococcal diseases, prion diseases, rabies, and tuberculosis). Conclusion The priority entities agreed with those of the WHO in 2023; almost all were currently covered by the French surveillance and alert system. Repeating this analysis periodically would keep the list updated.
Mots clés Multi-criteria decision analysis, Epidemiology, Surveys and Questionnaires, PUBLIC HEALTH, Humans, Health Priorities, France, Decision Support Techniques, Communicable Diseases
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Résumé This study first time explores the impact of total factor productivity, renewable energy, exports, imports, and income on carbon emissions in the Gas Exporting Countries Forum (GECF) nations. To ensure that the results are sound and policy insights are well-grounded, three main issues of panel data – cross-sectional dependency, heterogeneity, and nonstationarity – are addressed using cutting-edge methods. Moreover, a theoretically justified framework is employed, offering advantages such as considering a broad set of factors, which are actionable from a climate policy perspective, with dual benefits of emissions reduction and supporting clean growth. We find that total factor productivity, renewable energy, and exports reduce carbon emissions, while income and imports have an increasing effect. Policymakers in GECF countries may consider implementing measures to support technological advancements, efficiency improvements, increased use of renewable energy, expanded exports, and lowered imports. They can reduce emissions while promoting sustainable economic growth.
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Résumé This paper utilizes data from the 2017 China Household Finance Survey (CHFS) to examine the impact of loss aversion on individuals' willingness to relocate due to environmental concerns. We find that individuals who are more loss averse are less likely to consider moving, resulting in what is called the status-quo bias. In addition, we find that individuals with stronger family ties as measured by the number of siblings and higher household fixed assets are more susceptible to these effects, implying that they are more attached to their current place of residence and less likely to relocate.We thank Ling Zhou and one anonymous referee for constructive comments.
Mots clés Family ties, Status-quo bias, Loss aversion, Willingness to relocate
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Résumé This paper uses French data to simultaneously estimate the impact of two types of connections on government subsidies allocated to municipalities. Investigating different types of connection in a same setting helps to distinguish between the different motivations that could drive pork-barreling. We differentiate between municipalities where ministers held office before their appointment to the government and those where they lived as children. Exploiting ministers' entries into and exits from the government, we show that municipalities where a minister was mayor receive 30% more investment subsidies when the politician they are linked to joins the government, and a similar size decrease when the minister departs. In contrast, we do not observe these outcomes for municipalities where ministers lived as children. These findings indicate that altruism toward childhood friends and family does not fuel pork-barreling, and suggest that altruism toward adulthood social relations or career concerns matter. We also present complementary evidence suggesting that observed porkbarreling is the result of soft influence of ministers, rather than of their formal control over the administration they lead.✩ This paper was previously circulated under the titles ''What motivates French pork: Political career concerns or private connections?'' and ''The returns from private and political connections: New evidence from French municipalities''. We greatly appreciated comments and suggestions from three anonymous reviewers, the Editor,
Mots clés Personal connections, Political connections, Distributive politics, Local favoritism
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Résumé Under incomplete contracts, the mutual belief in reciprocity facilitates how traders create value through economic exchange. Creating such beliefs among strangers can be challenging even when they are allowed to communicate, because communication is cheap. In this paper, we first extend the literature showing that a truth-telling oath increases honesty to a sequential trust game with pre-play, fixed-form, and cheap-talk communication. Our results confirm that the oath creates more trust and cooperative behavior thanks to an improvement in communication; but we also show that the oath induces selection into communication -it makes people more wary of using communication, precisely because communication speaks louder under oath. We next designed additional treatments featuring mild and deterrent fines for deception to measure the monetary equivalent of the non-monetary incentives implemented by a truth-telling oath. We find that the oath is behaviorally equivalent to mild fines. The deterrent fine induces the highest level of cooperation. Altogether, these results confirm that allowing for interactions under oath within a trust game with communication creates significantly more economic value than the identical exchange institutions without the oath.
Mots clés Trust game, Cooperation, Communication, Commitment, Deception, Fine, Oath
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Résumé We estimate the causal effect of losing a father in the U.S. Civil War on children's long-run socioeconomic outcomes. Linking military records from the 2.2 million Union Army soldiers with the 1860 U.S. population census, we track soldiers' sons into the 1880 and 1900 census. Sons of soldiers who died had lower occupational income scores and were less likely to work in a high-or semiskilled job as opposed to being low-skilled or farmers. These effects persisted at least until the 1900 census. Our results are robust to instrumenting paternal death with the mortality rate of the father's regiment, which we argue was driven by military strategy that did not take into account the social origins of soldiers. Prewar family wealth is a strong mitigating factor: there is no effect of losing a father in the top quartile of the wealth distribution.
Mots clés US civil war, Orphans, Intergenerational Mobility
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Résumé This paper considers a risk-neutral insurer and a risk-averse individual who bargain over the terms of an insurance contract. Under asymmetric Nash bargaining, we show that the Pareto-optimal insurance contract always contains a straight deductible under linear transaction costs and that the deductible disappears if and only if the deadweight cost is zero, regardless of the insurer’s bargaining power. We further find that the optimality of no insurance is consistent across all market structures. When the insured’s risk preference exhibits decreasing absolute risk aversion, the optimal deductible and the insurer’s expected loss decrease in the degree of the insured’s risk aversion and thus increase in the insured’s initial wealth. In addition, the effect of increasing the insurer’s bargaining power on the optimal deductible is equivalent to a pure effect of reducing the initial wealth of the insured. Our results suggest that the well-documented preference for low deductibles could be the result of insurance bargaining.
Mots clés Asymmetric Nash bargaining, Risk sharing, Deductible insurance, Wealth effect, Overinsurance
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Résumé Quels facteurs peuvent prédire qu’une personne respectera les mesures sanitaires liées au COVID-19, comme le port du masque ou le confinement ? Cet article examine la précaution des individus, en mesurant leur degré d’adhésion déclaré au principe de précaution. Ce dernier est particulièrement pertinent pour les situations liées au COVID-19, car il stipule que, face à un risque potentiellement important, des mesures devraient être prises quand bien même les relations de causalité n’auraient pas été scientifiquement totalement établies. Nous avons réalisé une enquête en ligne auprès d’un échantillon représentatif (N = 1 154) de la population française en mai 2020. Les résultats montrent, même après avoir contrôlé l’aversion au risque, que l’adhésion au principe de précaution est positivement corrélée au respect de chacune des six mesures sanitaires considérées. Plan 1. Introduction 2. Matériel et méthodes 3. Résultats 4. Discussion 5. Conclusion : cibler le principe de précaution pour améliorer le respect des mesures sanitaires ? — Financement — Déclaration d’approbation éthique
Mots clés Precautionary principle, Individual behavior, Risk, Sanitary measures, COVID-19, Principe de précaution, COVID-19, Comportement individuel, Risque, Mesures sanitaires
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Résumé We investigate how the incompleteness of an employment contract—discretionary and noncontractible effort—can affect an employer’s decision about cutting nominal wages. Using matched employer-employee payroll data from Great Britain linked to a survey of managers, we find support for the main predictions of a stylized theoretical framework of wage determination: nominal cuts are at most half as likely when managers believe that their employees have significant discretion over how they do their work, although the involvement of employees, via information sharing, reduces this correlation. We also describe how contract incompleteness and wage cuts vary across different jobs. These findings provide the first observational quantitative evidence that managerial beliefs about contractual incompleteness can account for their hesitancy over nominal wage cuts. This has long been conjectured by economists based on anecdotes, qualitative surveys, and laboratory and field experiments.
Mots clés Wave rigidity, Employment contract, Workplace relations, Employer-employee data, Pay change
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Résumé What patterns of economic relations arise when people are altruistic rather than strategically self-interested? What are the welfare implications of altruistically-motivated choices of business partners? This paper introduces an altruism network into a simple model of choice among partners for economic activity. With concave utility, agents effectively become inequality averse towards their friends and family. Rich agents preferentially choose to work with poor friends despite productivity losses. These preferential contracts can also align with welfare since the poor benefit the most from income gains and these gains can outweigh the loss in output. Hence, network inequality—the divergence in incomes within sets of friends and family—is key to how altruism shapes economic activity, output, and welfare. When skill homophily —the tendency for friends to have the skills needed for high production—is high, preferential contracts and productivity losses disappear since rich agents have poor friends with the requisite qualifications.
Mots clés Networks, Altruism, Income inequality, Connections
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Résumé This paper derives closed‐form solutions for a strategic , simultaneous harvesting in a predator–prey system. Using a parametric constraint, it establishes the existence and uniqueness of a linear feedback‐Nash equilibrium involving two specialized fleets and allows for continuous time results for a class of payoffs that have constant elasticity of the marginal utility. These results contribute to the scarce literature on analytically tractable predator–prey models with endogenous harvesting. A discussion based on industry size effects is provided to highlight the role played by biological versus strategic interactions in the multispecies context. Recommendations for Resource Managers This model presents a thorough examination of the economic inefficiencies inherent in the exploitation dynamics of two interdependent species, elucidating the complex interplay between ecological interactions and economic outcomes. The size of the fishing industries constitutes a significant variable that must be integrated into the formulation of pertinent policy recommendations. This constitutes an advancement towards a more time‐consistent approach to Ecosystem‐Based Fishery Management (EBFM).
Mots clés Common‐pool resource, Dynamic games, Fisheries, Predator–preyrelationship
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Résumé This study examines the acceptance of artificial intelligence (AI)-based diagnostic alternatives compared to traditional biological testing through a randomized scenario experiment in the domain of neurodegenerative diseases (NDs). A total of 3225 pairwise choices of ND risk-prediction tools were offered to participants, with 1482 choices comparing AI with the biological saliva test and 1743 comparing AI+ with the saliva test (with AI+ using digital consumer data, in addition to electronic medical data). Overall, only 36.68% of responses showed preferences for AI/AI+ alternatives. Stratified by AI sensitivity levels, acceptance rates for AI/AI+ were 35.04% at 60% sensitivity and 31.63% at 70% sensitivity, and increased markedly to 48.68% at 95% sensitivity (p
Mots clés Artificial intelligence, AI diagnostics, Neurodegenerative diseases, Machine learning
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Résumé Is elite persistence weaker in Africa than in other parts of the world, given historical barriers to intergenerational inheritance of status, such as limited private property rights and frequent economic and political crises? In the absence of linked intergenerational data, we use name analysis to address this question. Using surnames associated with two Sierra Leonean elites, Krio descendants of settlers and members of chiefly lineages, we measure elite persistence in politics, education and business since 1960. Both groups were highly overrepresented in elite positions at independence, and remain overrepresented today. Benchmarking our results against other countries shows that Sierra Leone's educational elites are as persistent as elsewhere, but elite persistence in the political sphere is lower than in the United Kingdom, our main comparator. We also show marked path dependence: chiefly descendants remain more overrepresented in politics and mining, while the Krio are highly over-represented in education and the professions.
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Résumé We study how altruism networks affect the demand for formal insurance. Agents with CARA utilities are connected through a network of altruistic relationships. Incomes are subject to a common shock and to a large individual shock, generating heterogeneous damages. Agents can buy formal insurance to cover the common shock, up to a coverage cap. We find that ex-post altruistic transfers induce interdependence in ex-ante formal insurance decisions. We characterize the Nash equilibria of the insurance game and show that agents act as if they are trying to maximize the expected utility of a representative agent with average damages. Altruism thus tends to increase demand of low-damage agents and to decrease demand of high-damage agents. Its aggregate impact depends on the interplay between demand homogenization, the zero lower bound and the coverage cap. We find that aggregate demand is higher with altruism than without altruism at low prices and lower at high prices. Nash equilibria are constrained Pareto efficient.
Mots clés Informal transfers, Altruism networks, Formal insurance
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