Publications

Résumé This paper aims to present a new explanation for environmental traps through the presence of endogenous hazard rate. We show that adaptation and mitigation policies affect the occurrence of environmental traps differently. The former could cause environmental traps, whereas the latter could help society avoid such traps by decreasing the probability of a harmful event occurring. As a result, we present a new trade-off between adaptation and mitigation policies different than the usual dynamic trade-off that is highlighted in many studies and is crucial to developing countries. Contrary to the literature, when an economy is in a trap, an economy with a high environmental quality equilibrium tends to be more conservative in terms of resource exploitation than an economy with a low environmental quality equilibrium, which implies a heterogeneous reaction against the endogenous hazard rate.
Mots clés Mitigation, Adaptation, Multiple equilibria, Tipping points, Occurrence hazard, Harmful event
Publication HAL Google Scholar
Résumé Using data in the United States, UK and Germany, we show that women whose working hours exceed those of their male partners report lower life satisfaction on average. By contrast, men do not report lower life satisfaction from working more hours than their female partners. An analysis of possible mechanisms shows that in couples where the woman works more hours than the man, women do not spend significantly less time doing household chores. Women with egalitarian ideologies are likely to perceive this unequal division of labour as unfair, ultimately reducing their life satisfaction.
Mots clés Gender identity, Fairness, Relative working hours, Life satisfaction, Housework
Publication HAL Google Scholar
Résumé In this paper, we extend the general descent method proposed by Attouch, Bolte and Svaiter [Math. Program. 137 (2013), 91-129] to deal with possible asymmetric like-distances. Using a w-distance as regularization term our results guarantee the convergence of bounded sequences, under the assumption that the objective function satisfies the Kurdyka-Łojasiewicz inequality. In particular, it improves some existing works on proximal point methods with quasi-distance as regularization term because we prove convergence of bounded sequences without any additional assumption on the w-distance unlike it have been done with quasi-distances. The last section gives an application relative to the emergence of habits after a succession of worthwhile moves which balance motivation and resistance to move.
Mots clés Variational rationality, Habits, W-distance, Kurdyka-Łojasiewicz inequality, Descent methods
Publication HAL Google Scholar
Résumé Introduction to the thematic issue on government‐provided services
Publication HAL Google Scholar
Résumé The marketing-mix of price–quality and advertising–quality relationship is well studied. Less understood is the price–advertising–quality relationship. This article fills the gap, investigating the interplay between price, advertising, and quality in an optimal control model. Our results generalize the condition of Dorfman–Steiner in a dynamic context. Also, they point to the impact of greater product quality on the dynamic policies of pricing and advertising. Furthermore, a phase diagram analysis shows that quality develops monotonically in time and converges to a unique steady state. We also show that quality investment could either decrease or increase over time but this depends on its effectiveness. Our results spot the profitable opportunities of a firm managing a more complex marketing-mix.
Mots clés Price–advertising–quality relationship Dynamic pricing Dynamic advertising Marketing mix Condition of Dorfman–Steiner
Publication HAL Google Scholar
Résumé We survey the recent, fast-growing literature on peer effects in networks. An important recurring theme is that the causal identification of peer effects depends on the structure of the network itself. In the absence of correlated effects, the reflection problem is generally solved by network interactions even in nonlinear, heterogeneous models. By contrast, microfoundations are generally not identified. We discuss and assess the various approaches developed by economists to account for correlated effects and network endogeneity in particular. We classify these approaches in four broad categories: random peers, random shocks, structural endogeneity, and panel data. We review an emerging literature relaxing the assumption that the network is perfectly known. Throughout, we provide a critical reading of the existing literature and identify important gaps and directions for future research.
Mots clés Measurement errors, Randomization, Causal effects, Identification, Peer effects, Social networks
Publication HAL Google Scholar
Résumé This paper analyses the evolution of COVID-19 in Cameroon over the period March 6-April 2020 using SIR models. Specifically, we 1) evaluate the basic reproduction number of the virus, 2) determine the peak of the infection and the spread-out period of the disease, and 3) simulate the interventions of public health authorities. Data used in this study is obtained from the Cameroonian Public Health Ministry. The results suggest that over the identified period, the reproduction number of COVID-19 in Cameroon is about 1.5, and the peak of the infection should have occurred at the end of May 2020 with about 7.7% of the population infected. Furthermore, the implementation of efficient public health policies could help flatten the epidemic curve.
Mots clés Infectious disease control, Hygiene, Viral evolution, Respiratory infections, Infectious disease epidemiology, Cameroon, Public and occupational health, COVID 19
Publication HAL Google Scholar
Résumé The logarithmic prices of financial assets are conventionally assumed to follow a drift–diffusion process. While the drift term is typically ignored in the infill asymptotic theory and applications, the presence of temporary nonzero drifts is an undeniable fact. The finite sample theory for integrated variance estimators and extensive simulations provided in this paper reveal that the drift component has a nonnegligible impact on the estimation accuracy of volatility, which leads to a dramatic power loss for a class of jump identification procedures. We propose an alternative construction of volatility estimators and observe significant improvement in the estimation accuracy in the presence of nonnegligible drift. The analytical formulas of the finite sample bias of the realized variance, bipower variation, and their modified versions take simple and intuitive forms. The new jump tests, which are constructed from the modified volatility estimators, show satisfactory performance. As an illustration, we apply the new volatility estimators and jump tests, along with their original versions, to 21 years of 5-minute log returns of the NASDAQ stock price index.
Mots clés Jumps, Volatility estimation, Finite sample theory, Nonzero drift, Diffusion process
Publication HAL Google Scholar
Résumé In their quest for universal health coverage (UHC), many developing countries use alternative financing strategies including general revenues to expand health coverage to the whole population. Unless a policy adjustment is undertaken, future generations may foot the bill of the UHC. This raises the important policy questions of who bears the burden of UHC and whether the UHC-fiscal stance is sustainable in the long term. These two questions are addressed using an overlapping generations model within a general equilibrium (OLG-CGE) framework applied to Palestine. We assess and compare alternative ways of financing the UHC-ridden deficit (viz. deferred-debt, current and phased-manner finance) and their implications on fiscal sustainability and intergenerational inequalities. The policy instruments examined include direct labour-income tax and indirect consumption taxes as well as health insurance contributions. Results show that in the absence of any policy adjustment, the implementation of UHC would explode the fiscal deficit and debt-GDP ratio. This indicates that the UHC-fiscal stance is rather unsustainable in the long term, thus, calling for a policy adjustment to service the UHC debt. Among the policies we examined, a current rather than deferred-debt finance through consumption taxation emerged to be preferred over other policies in terms of its implications for both fiscal sustainability and intergenerational inequality.
Mots clés Fiscal sustainability, Computable general equilibrium, Overlapping generations, Universal health coverage, Intergenerational inequality
Publication HAL Google Scholar
Résumé In this article, we studied geographic variation in the use of personalized genetic testing for advanced non-small cell lung cancer (NSCLC) and we evaluated the relationship between genetic testing rates and local socioeconomic and ecological variables. We used data on all advanced NSCLC patients who had a genetic test between April 2012 and April 2013 in France in the frame of the IFCT Biomarqueurs-France study (n = 15814). We computed four established measures of geographic variation of the sex-adjusted rates of genetic testing utilization at the "départment" (the French territory is divided into 94 administrative units called 'départements') level. We also performed a spatial regression model to determine the relationship between département-level sex-adjusted rates of genetic testing utilization and economic and ecological variables. Our results are the following: (i) Overall, 46.87% lung cancer admission patients obtained genetic testing for NSCLC; département-level utilization rates varied over 3.2-fold. Measures of geographic variation indicated a relatively high degree of geographic variation. (ii) there was a statistically significant relationship between genetic testing rates and per capita supply of general practitioners, radiotherapists and surgeons (negative correlation for the latter); lower genetic testing rates were also associated with higher local poverty rates. French policymakers should pursue effort toward deprived areas to obtain equal access to personalized medicine for advanced NSCLC patients.
Mots clés Personalized medicine, Biogeography, Physicians, Human genetics, France, Lung and intrathoracic tumors, Non-small cell lung cancer, Genetic testing
Publication HAL Google Scholar
Résumé As Ricoeur acknowledges, the publication of Rawls’s book, A Theory of Justice(TJ), in 1971 was a major event in the area of contemporary political philoso-phy. Ricoeur offers important comments on Rawls’s approach to justice. These commentaries are mainly based on a close reading of this book. This article focuses on such commentaries. They are at the same time glowing and critical. Ricoeur expresses his support to Rawls for his illuminating study of justice, seen as a virtue of institutions. ...
HAL Google Scholar
Résumé OECD countries have experienced a large increase in top wage inequality. Atkinson (2008) attributes this phenomena to the superstar theory leading to a Pareto tail in the wage distribution with a low Pareto coefficient. Do we observe a similar phenomena for academic wages? We examine wage formation in a public US university using for each academic rank a hybrid mixture formed by a lognormal distribution for regular wages and a Pareto distribution for top wages, using a Bayesian approach. The presence of superstars wages would imply a higher dispersion in the Pareto tail than in the lognormal body. We concluded that academic wages are formed in a different way than other top wages. There is an effort to propose competitive wages to some young Assistant Professors. But when climbing up the wage ladder, we found a phenomenon of wage compression which is just the contrary of a superstar phenomenon.
Mots clés Wage compression, Wage formation, Tournaments theory, Hybrid mixtures, Bayesian inference, Academic market, Superstar wages
Publication HAL Google Scholar
Résumé The purpose of this paper is twofold. First, we examine convergence properties of an inexact proximal point method with a quasi distance as a regularization term in order to find a critical point (in the sense of Toland) of a DC function (difference of two convex functions). Global convergence of the sequence and some convergence rates are obtained with additional assumptions. Second, as an application and its inspiration, we study in a dynamic setting, the very important and difficult problem of the limit of the firm and the time it takes to reach it (maturation time), when increasing returns matter in the short run. Both the formalization of the critical size of the firm in term of a recent variational rationality approach of human dynamics and the speed of convergence results are new in Behavioral Sciences.
Mots clés Variational rationality, Proximal point method, Kurdyka–Łojasiewicz inequality, DC function, Limit of the firm
Publication HAL Google Scholar
Résumé This paper investigates the link between parental separation and children's achievement in adulthood. Using a French dataset on “Education-Training-Employment”, I first estimate a random effects model and then examine the differences in age at divorce for children within the same family, to control for divorced family selection. Three outcomes are analysed: number of years of schooling, earnings-weighted education and social position. Using a random effects model, parental separation is linked to poorer educational attainment for their children, from 32% to 12% of a standard deviation lower where the number of years of education is concerned, and from 30% to 8% of a standard deviation lower where the earnings-weighted education is concerned. This effect varies with age: least affected are the 16 to 18-year-olds, and most affected are the youngest. Where social position is concerned, effects are weaker, but remain negative. Accounting for the family fixed effect yields somewhat weaker estimated effects for the youngest, but results remain similar. Parental separation is more detrimental to boys' education under both models, but conducting a F-test, we only reject the nul hypothesis for earnings-weighted education where family fixed effect is accounted for. In results from both models, teenagers who experience a parental separation are less affected if born after 1970, but differences are not statistically different from zero where the family fixed effect is accounted for.
Mots clés Marital Dissolution, Family Structure, Divorce, Education, Labour Market Outcomes
Publication HAL Google Scholar
Résumé We introduce an approach based on functional data analysis to identify patterns of malaria incidence to guide effective targeting of malaria control in a seasonal transmission area. Using functional data method, a smooth function (functional data or curve) was fitted from the time series of observed malaria incidence for each of 575 villages in west-central Senegal from 2008 to 2012. These 575 smooth functions were classified using hierarchical clustering (Ward’s method), and several different dissimilarity measures. Validity indices were used to determine the number of distinct temporal patterns of malaria incidence. Epidemiological indicators characterizing the resulting malaria incidence patterns were determined from the velocity and acceleration of their incidences over time. We identified three distinct patterns of malaria incidence: high-, intermediate-, and low-incidence patterns in respectively 2% (12/575), 17% (97/575), and 81% (466/575) of villages. Epidemiological indicators characterizing the fluctuations in malaria incidence showed that seasonal outbreaks started later, and ended earlier, in the low-incidence pattern. Functional data analysis can be used to identify patterns of malaria incidence, by considering their temporal dynamics. Epidemiological indicators derived from their velocities and accelerations, may guide to target control measures according to patterns.
Mots clés Malaria dynamic, Malaria patterns, Time series clustering, Functional data analysis
Publication HAL Google Scholar
Résumé Although it is widely acknowledged that non-cognitive skills matter for adult outcomes, little is known about the role played by family environment in the formation of these skills. We use a longitudinal survey of children born in the UK in 2000–2001, the Millennium Cohort Study by the Centre for Longitudinal Studies, to estimate the effect of family size on socio-emotional skills, measured by the Strengths and Difficulties Questionnaire. To account for the endogeneity of fertility decisions, we use a well-known instrumental approach that exploits parents’ preference for children’s gender diversity. We show that the birth of a third child negatively affects the socio-emotional skills of the first two children in a persistent manner. However, we show that this negative effect is entirely driven by girls. We provide evidence that this gender effect is partly driven by an unequal response of parents’ time investment in favour of boys and, to a lesser extent, by an unequal demand for household chores.
Mots clés Non-cognitive skills, Family size, Birth order, Child development
Publication HAL Google Scholar
Résumé This chapter discusses the potential impacts of the spread of COVID-19, and the restriction policies that it has triggered in many countries, on conflict incidence worldwide. Based on anecdotal evidence and recent research, we argue that imposing nation-wide shutdown policies diminishes conflict incidence on average, but that this conflict reduction may be short-lived and highly heterogeneous across countries. In particular, conflict does not appear to decline in poor, fractionalised countries. Evidence points to two potential ways in which COVID-related restriction policies may increase conflict: losses in income and magnified ethnic and religious tensions leading to scapegoating of minorities.
HAL Google Scholar
Résumé In this paper, we develop a unified spatial model of turnout and voting behaviors in which citizens can identify with one or two parties. We show the existence of a conflicted voter's curse: If there is no position that reconciles the ideological views of both parties, it is always rational for citizens that identify with two parties to abstain even if they are a majority. In a two-candidate electoral competition, the conflicted voter's curse implies that candidates converge to the center of the political domain if and only if conflicted voters are pivotal and the parties have shared ideological views. Otherwise, we show that candidates may converge or diverge depending upon the degree of party polarization and whether candidates care about ideology or not. Our analysis suggests that the behavior of conflicted voters may be relevant for electoral outcomes and public choice.
Mots clés Party polarization, Electoral competition, Conflicted voters, Party identification, Spatial voting
Publication HAL Google Scholar
Résumé Background: Compared to the number of studies performed in the United States, few studies have been conducted on the link between health insurance and healthcare consumption in Europe, likely because most European countries have compulsory national health insurance (NHI) or a national health service (NHS). Recently, a major French private insurer, offering voluntary complementary coverage in addition to the compulsory NHI, replaced its single standard package with a range of offers from basic coverage (BC) to extended coverage (EC), providing a quasi-natural experiment to test theoretical assumptions about consumption patterns. Methods: Reimbursement claim data from 85,541 insurees were analysed from 2009 to 2018. Insurees who opted for EC were matched to those still covered by BC with similar characteristics. Difference-indifferences (DiD) models were used to compare both the monetary value and physical quantities of healthcare consumption before and after the change in coverage. Results: As expected, the DiD models revealed a strong significant, though transitory (mainly during the first year), increase after the change in coverage for EC insurees, particularly for costly care such as dental prostheses and spectacles. Surprisingly, consumption seemed to precede the change in coverage, suggesting that one possible determinant of opting for more coverage may be previous unplanned expenses. Conclusion: Both catching-up behaviour and moral hazard are likely to play a role in the increase observed in healthcare consumption.
Mots clés Difference-in-differences, Exact matching, Longitudinal data, Healthcare consumption, Moral hazard, Complementary health insurance
Publication HAL Google Scholar