Portail HAL Paris School of Economics (PSE)
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Opposite ethical views converge under the threat of catastrophic climate change
No full textInternational audienceClimate policy is often described by economists as an intertemporal consumption trade-off: consume all you want today and face climate damages in the future, or sacrifice consumption today to implement costly climate policies that will bring future benefits through avoided climate damages. If one assumes enduring technological progress, a society that is more averse to intertemporal inequalities should postpone climate policies and let future, richer generations pay more. Growing evidence however suggests that the trade-off is more complex: abrupt, extreme, irreversible changes to the climate may cause discontinuities to socio-economic systems, possibly leading to a sharp decline of human population and consumption per capita. In this paper, we show that, when accounting for a very small risk of catastrophic climate change, it is optimal to pursue stringent climate policies to postpone the catastrophe. Our results conform with the well-known conclusion that tight carbon budgets are preferred when aversion towards inequalities between generations is low. However, by contrast with previous studies, we show that stringent policies are also optimal when inequality aversion is high. The non-monotonicity of the influence of inequality aversion is due to the fact that, for a given investment in abatement, a higher inequality aversion gives a smaller weight to avoided future non-catastrophic damages, but a larger weight to the catastrophic outcome. We also explore the role of population ethics, and show that the size of the optimal carbon budget decreases with the social preference for large populations, although this parameter plays almost no role at extreme levels of inequality aversion. Our result demonstrates that views from opposite sides of the ethical spectrum in terms of inequality aversion converge in terms of climate policy recommendations, warranting immediate climate action
Insurance Supervision under Climate Change: A Pioneers Detection Method
No full textI present the Pioneers Detection Method, a supervisory tool I developed to enhance resilience in insurance markets facing the challenges posed by climate change. Based on a theoretical model of the insurance industry, I consider a scenario in which independent experts determine premiums according to their individual risk assessments. Due to the segmented nature of the private insurance market, accurately estimating the tail parameter of loss distribution is difficult, especially given the rarity of extreme events. My method leverages temporal directional change and convergence to integrate expert opinions, giving greater emphasis to those who effectively identify trend shifts after climatic tipping points. A series of simulations reveals that the Pioneers Detection Method outperforms traditional pooling methods within a Bayesian framework. Furthermore, this approach appears to be notably effective in improving welfare in an insurance market with a limited number of private entities
Exchange Rate Policy and Firm Heterogeneity
No full textInternational audienceThis paper examines the exchange rate policy in a tractable framework with heterogeneous firms, incomplete financial markets and nominal rigidities. External demand shocks generate exchange rate movements leading to uncertainty in the labor demand of exporter firms. When exporter firms are homogeneous in terms of productivity, a monetary policy response to external demand shocks stabilizes the export market and improves welfare, thus providing a rationale for managed exchange rate policies
Losing on the Home Front? Battlefield Casualties, Media, and Public Support for Foreign Interventions
No full textHow domestic constituents respond to signals of weakness in foreign wars remains an important question in international relations. In this paper, we study the impact of battlefield casualties and media coverage on public demand for war termination. To identify the effect of troop fatalities, we leverage the otherwise exogenous timing of survey collection across 26,776 respondents from nine members of the International Security Assistance Force (ISAF) in Afghanistan. Quasi-experimental evidence demonstrates that battlefield casualties increase coverage of the Afghan conflict and public demand for withdrawal, with heterogeneous effects consistent with an original theoretical argument. Evidence from a survey experiment replicates the main results. To shed light on the media mechanism, we leverage a news pressure design and find that major sporting matches occurring around the time of battlefield casualties drive down subsequent coverage, and significantly weaken the effect of casualties on support for war termination. These results highlight the crucial role that media play in shaping public support for foreign military interventions
« Football is not a Big Business but is Doing Well » ou la transformation du modèle économique du football anglais
No full textInternational audienceHow can we explain economically the shift from the people’s game to the global game? Why Manchester City, for example, whose origins lie in parochial paternalism at St Mark’s, can today adopt a strategy of global football domination through the City Football Group? The answer to these questions is, of course, multifaceted and based on a non-linear history. Football was very popular from its origins until the 1950s and 1960s. The beautiful game then entered its “dark” period for various reasons: recession in the 1980s, obsolescence of the stadiums, hooliganism, among others. The “renaissance” from the 1990s onwards was driven in particular by the creation of the Premier League, the very strong growth in TV rights and the globalization of English football.Comment expliquer économiquement le passage du people’s game au global game ? Pourquoi Manchester City, par exemple, dont les origines se trouvent dans un paternalisme paroissial à St Mark’s peut adopter aujourd’hui une stratégie de domination mondiale du football à travers le City Football Group ? La réponse à ces questions est bien entendu plurielle et s’appuie sur une histoire non linéaire. Le football connait un fort succès populaire depuis ses origines jusqu’aux années 1950-1960. Le beautiful game entre ensuite dans sa période « sombre » pour différentes raisons : récession des années 1980, vétusté des stades, hooliganisme, entre autres. La « renaissance » à partir des années 1990 se nourrit notamment de la création de la Premier League, de la très forte croissance des droits TV et de la mondialisation du football anglais
Maternal genetic risk for depression and child human capital
No full textInternational audienceWe here address the causal relationship between the maternal genetic risk for depression and child human capital using UK birth-cohort data. We find that an increase of one standard deviation (SD) in the maternal polygenic risk score for depression reduces their children's cognitive and non-cognitive skill scores by 5 to 7% of a SD throughout adolescence. Our results are robust to a battery of sensitivity tests addressing, among others, concerns about pleiotropy and dynastic effects. Our Gelbach decomposition analysis suggests that the strongest mediator is genetic nurture (through maternal depression itself), with genetic inheritance playing only a marginal role
How Overconfidence Bias Influences Suboptimality in Perceptual Decision Making
No full textInternational audienceIn perceptual decision making, it is often found that human observers combine sensory information and prior knowledge suboptimally. Typically, in detection tasks, when an alternative is a priori more likely to occur, observers choose it more frequently to account for the unequal base rate but not to the extent they should, a phenomenon referred to as “conservative decision bias” (i.e., observers do not shift their decision criterion enough). One theoretical explanation of this phenomenon is that observers are overconfident in their ability to interpret sensory information, resulting in overweighting the sensory information relative to prior knowledge. Here, we derived formally this candidate model, and we tested it in a visual discrimination task in which we manipulated the prior probabilities of occurrence of the stimuli. We measured confidence in decisions and decision criterion placement in two separate experimental sessions for the same participants (N = 69). Both overconfidence bias and conservative decision bias were found in our data, but critically the link that was predicted between these two quantities was absent. Our data suggested instead that when informed about the a priori probability, overconfident participants put less effort into processing sensory information. These findings offer new perspectives on the role of overconfidence bias to explain suboptimal decisions
Une histoire du conflit politique. Elections et inégalités sociales en France. 1789-2022.
No full textInternational audienceQui vote pour qui et pourquoi ? Comment la structure sociale des électorats des différents courants politiques en France a-t-elle évolué de 1789 à 2022 ? En s’appuyant sur un travail inédit de numérisation des données électorales et socio-économiques des 36 000 communes de France couvrant plus de deux siècles, cet ouvrage propose une histoire du vote et des inégalités à partir du laboratoire français.Au-delà de son intérêt historique, ce livre apporte un regard neuf sur les crises du présent et leur possible dénouement. La tripartition de la vie politique issue des élections de 2022, avec d’une part un bloc central regroupant un électorat socialement beaucoup plus favorisé que la moyenne – et réunissant d’après les sources ici rassemblées le vote le plus bourgeois de toute l’histoire de France –, et de l’autre des classes populaires urbaines et rurales divisées entre les deux autres blocs, ne peut être correctement analysée qu’en prenant le recul historique nécessaire. En particulier, ce n’est qu’en remontant à la fin du 19e siècle et au début du 20e siècle, à une époque où l’on observait des formes similaires de tripartition avant que la bipolarisation ne l’emporte pendant la majeure partie du siècle dernier, que l’on peut comprendre les tensions à l’œuvre aujourd’hui. La tripartition a toujours été instable alors que c’est la bipartition qui a permis le progrès économique et social. Comparer de façon minutieuse les différentes configurations permet de mieux envisager plusieurs trajectoires d’évolutions possibles pour les décennies à venir.Une entreprise d’une ambition unique qui ouvre des perspectives nouvelles pour sortir de la crise actuelle. Toutes les données collectées au niveau des 36 000 communes de France sont disponibles en ligne en accès libre sur le site une histoire du conflit politique.fr, qui comprend des centaines de cartes, graphiques et tableaux interactifs auxquels le lecteur pourra se reporter afin d’approfondir ses propres analyses et hypothèses
Impact of tariff refinement on the choice between scheduled C‐section and normal delivery: Evidence from France
No full textInternational audienceStudying quasi-experimental data from French hospitals from 2010 to 2013, we test the effects of a substantial diagnosis-related group (DRG) tariff refinement that occurred in 2012, designed to reduce financial risks of French maternity wards. To estimate the resulting DRG incentives with regard to the choice between scheduled C-sections and other modes of child delivery, we predict, based on pre-admission patient characteristics, the probability of each possible child delivery outcome and calculate expected differences in associated tariffs. Using patient-level administrative data, we find that introducing additional severity levels and clinical factors into the reimbursement algorithm had no significant effect on the probability of a scheduled C-section being performed. The results are robust to multiple formulations of DRG financial incentives. Our paper is the first study that focuses on the consequences of a DRG refinement in obstetrics and develops a probabilistic approach suitable for measuring the expected effects of DRG fee incentives in the presence of multiple tariff groups
Everyday econometricians: Selection neglect and overoptimism when learning from others
No full textThis study explores selection neglect in an experimental investment game where individuals can learn from others' outcomes. Experiment 1 examines aggregate-level equilibrium behavior. We find strong evidence of selection neglect and corroborate several comparative static predictions of Jehiel's (2018) model, showing that the severity of the bias is aggravated by the sophistication of other individuals and moderated when information is more correlated across individuals. Experiment 2 focuses on individual decision-making, isolating the influence of beliefs from possible confounding factors. This allows us to classify individuals according to their degree of naivety and explore the limits of, and potential remedies for, selection neglect