Documents de travail

Résumé We formulate a hydro-economic model of the NorthWestern Sahara Aquifer System (NWSAS) to assess the effects of intensive pumping on the groundwater stock and examine the subsequent consequences of aquifer depletion. This large system comprises multi-layer reservoirs with vertical exchanges, all exploited under open access properties. We first develop a theoretical model to account for relevant features of the NWSAS by introducing, in the standard Gisser-Sanchez model, a non-stationary demand and quadratic stock-dependent cost functions. In the second step, we calibrate parameters values using data from the NWSAS over 1955-2000. We finally simulate the time evolution of the aquifer system with exploitation under an open-access regime. We specifically examine time trajectories of the piezometric levels in the two reservoirs, the natural outlets, and the modification of water balances. We find that natural outlets of the two reservoirs might be totally dried before 2050.
Mots clés Groundwater-dependant ecosystems, Semi-arid region, Simulation, Multi aquifer system, Private pumping, Hydro-economic model
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Résumé We revisit the canonical policy of eliminating capital taxation by increasing labor taxation in a endogenous-labor, heterogeneous-agent model with income and wealth heterogeneity, when the government is subject to a strict (per-period) balancedbudget constraint. By contrast with its non-budget neutral equivalent-associated with a constant tax rate over time and a permanent increase in the level of public debt-we show that the obtained endogenous path for the labor tax rate is sharply increasing in the initial period and decreasing over time. The policy then generates a deeper recession in the short-run and a greater expansion in the long-run, as well as a smaller decline in wealth inequality associated with a reduced incentive to save for precautionary motives. Overall, the policy still generates significant losses in average welfare.
Mots clés Wealth Redistribution, Heterogeneous agents, Tax Composition, Capital Tax Cut, Fiscal policy
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Résumé Revealed and stated preference techniques are widely used to assess willingness to pay (WTP) for non-market goods as input to public and private decision-making. However, individuals first have to satisfy subsistence needs through market good consumption, which affects their ability to pay. We provide a methodological framework and derive a simple ex post adjustment factor to account for this effect. We quantify its impacts on the WTP for non-market goods and the ranking of projects theoretically, numerically and empirically. This confirms that non-adjusted WTP tends to be plutocratic: the views of the richest-whatever they are-are more likely to impact decision-making, potentially leading to ranking reversal between projects. We also suggest that the subsistence needs-based adjustment factor we propose has a role to play in value transfer procedures. The overall goal is a better representation of the entire population's preferences with regard to non-market goods.
Mots clés Non-market valuation, Value transfer, Population&#039, s preferences, Adjustment factor, Subsistence needs
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Résumé Objectives: This note provides an assessment of COVID-19 acceleration among groups with different vaccine status in France. Methods: We assess viral acceleration using a novel indicator introduced in Baunez et al. (2021). The acceleration index relates the percentage change of tests that have been performed on a given day to the percentage change in the associated positive cases that same day. We compare viral acceleration among vaccinated and unvaccinated individuals in France over the period May 31st-August 29, 2021. Results: Once the state of the epidemic within each groups is accounted for, it turns out that viral acceleration has since mid-July converged to similar levels among vaccinated and unvaccinated individuals in France, even though viral speed is larger for the latter group compared to the former. Conclusion: Our results call for an increasing testing effort for both vaccinated and unvaccinated individuals, in view of the fact that viral circulation is currently accelerating at similar levels for both groups in France.
Mots clés COVID-19, Vaccine Status, Viral Acceleration, Acceleration Index, France
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Résumé We study how altruism networks affect the adoption of formal insurance. Agents have private CARA utilities and are embedded in a network of altruistic relationships. Incomes are subject to both a common shock and a large idiosyncratic shock. Agents can adopt formal insurance to cover the common shock. We show that ex-post altruistic transfers induce interdependence in ex-ante adoption decisions. We characterize the Nash equilibria of the insurance adoption game. We show that adoption decisions are substitutes and that the number of adopters is unique in equilibrium. The demand for formal insurance is lower with altruism than without at low prices, but higher at high prices. Remarkably, individual incentives are aligned with social welfare. We extend our analysis to CRRA utilities and to a fixed utility cost of adoption.
Mots clés Formal insurance, Informal transfers, Altruism networks
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Résumé This paper studies differences across genders in the re-contesting decisions of politicians following electoral wins or defeats. Using close races in mixed-gender French local elections, we show that women are less likely to persist in competition when they lose compared to male runners-up, but are equally or more prone than male winners to re-contest when they win. Differences in observable characteristics or in the expected electoral returns of running again cannot fully account for these gender gaps in persistence. In contrast, the heterogeneity of the results across political ideology, age, experience and occupation suggests that behavioural explanations are at play. Additionally, we provide evidence that a woman's victory encourages former female challengers to re-contest but does not trigger the entry of new female candidates.
Mots clés Self-selection, Elections, Candidates, Persistence, Competition, Gender
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Résumé This paper investigates the dependence of the Option-Adjusted Spread (OAS) for several ICE BofA Emerging Markets Corporate Plus Indexes to the outbreaks of the Covid-19 viral pandemics between March 1, 2020, and April 30, 2021. We investigate whether the number of new cases, the reproduction rate, death rate and stringency policies have resulted in an increase/decrease in the spreads. We study the bivariate distributions of epidemiological indicators and spreads to investigate their concordance using dynamic copula analysis and estimate the Kendall rankcorrelation coefficient. We also investigate the effect of the epidemiological variables on the extreme values of the spreads by fitting a tail index derived from a Pareto type I distribution. We highlight the existence of correlations, robust to the type of copulas used (Clayton or Gumbel). Moreover, we show that the epidemiological variables explain well the extreme values of the spreads.
Mots clés COVID-19, Corporate spreads, Pandemics, Emerging economies
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Résumé This paper provides a robust criterion for evaluating the allocation of opportunities among various groups. We envisage the problem of comparing these allocations from the view point of an ethical observer placed behind a veil of ignorance with respect to the group in which he/she could end up. We give justi…cation for such an ethical observer to evaluate these allocations of opportunities on the basis of an expected valuation of the expected utility of being in a group assuming an equal probability of falling in every group. We identify a criterion for comparing societies that is agreed upon by all such ethical observers who exhibit aversion to inequality of opportunities. The criterion happens to be a conic extension of zonotope inclusion criterion. We provide various interpretations of this criterion as well as some illustrations of its possible use, notably in the Indian context where we evaluate the inequalities of educational opportunities among castes and genders o¤ered by Indian states.
Mots clés Education, Gender, Zonotopes, Groups, Equalizing opportunities
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Résumé How do banking crises a ect rich, middle-class and poor households? This paper quanti es the distributional implications of banking crises for a panel of 140 economies over the 1970-2017 period. We rely on di erent empirical settings, including an instrumental variable approach, that exploit the geographical di usion of banking crises across borders. Our results show that banking crises systematically reduce the income share of rich households and positively a ect middle-class households. We also nd that income inequality increases during periods preceding the triggering of a banking crisis.
Mots clés Banking crises, Income distribution, Inequality
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Résumé There is no consensus among economists about the reasons why firms resort to profit sharing compensation, especially in larger firms. This paper presents evidence for France showing that firms with unions are more likely to resort to profit sharing than those without and, moreover, that strike incidence decreases with its usage. Inspired by these stylized facts, I develop a model to study the effects of profit sharing on union behavior that introduces two novel mechanisms. First, by making employee compensation depend on output, profit sharing makes unions internalize the cost of their strikes so that they are less inclined to organize collective actions. This in turn damages the credibility of their strike threats. Second, over time unions lose reputation, which further reduces their bargaining power. Lastly, I test the model using exogenous dates of elections of union representatives that give incentives for unions to organize collective actions in a competition for voters. I show that employers anticipate the effect of elections by increasing the usage of profit sharing. Its payment leads to a reduction in strike length the same year, and to a drop in wage growth by about 13 percent the year after. The effect is concentrated on lower occupations for whom wage growth is almost halved and driven by a reduction in the bargaining power of unions.
Mots clés Strikes, Reputation, Labor income inequality, Bargaining, Unions, Profit sharing
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