Publications

Abstract Considering optimal non-linear income tax problems when the social welfare function only depends on ranks as in Yaari (Econometrica 55(1):95–115, 1987) and weights agreeing with the Lorenz quasi-ordering, we extend the analysis of Simula and Trannoy (Am Econ J Econ Policy, 2021) in two directions. First, we establish conditions under which bunching does not occur in the social optimum. We find a sufficient condition on individual preferences, which appears as a reinforcement of the Spence-Mirrlees condition. In particular, the marginal dis-utility of gross income should be convex, but less convex the higher the productivity. We also show that, for all productivity distributions with a log-concave survival function, bunching is precluded under the maximin, Gini, and “illfare-ranked single-series Ginis”. Second, we turn to a discrete population setting, and provide an “ABC” formula for optimal marginal tax rates, which is related to those for a continuum of types found in Simula and Trannoy (2021), but remain essentially distinct.
Keywords Log-Concavity, Bunching, Optimal Income Taxation, Gini, Rank dependence
Publication HAL Google Scholar
Abstract This paper investigates how labour market regulations alter the adverse impact of rising import competition from China in European local labour markets between 1997 and 2006. The paper constructs measures of regional exposure to Chinese imports based on previous literature and on regional labour market frictions exploiting involuntary labour reallocations. Taking into account the endogeneity of import competition and its interaction with labour market regulations, the paper finds that regions more exposed to the rise of China have suffered from a reduction in manufacturing employment shares. This shock grows larger with regional labour market frictions; hence, it exacerbates the impact of trade shock on employment. Moreover, the paper finds that employment in public services, and not in construction or private services sector, absorbed the negative shock to the manufacturing sector. The unemployment rate, the labour force participation rate and wages in all sectors are unresponsive to import competition from China.
Keywords Empirical trade, Employment structure, Labour reallocation, Regional labour markets
Publication HAL Google Scholar
Abstract Under income-differentiated mortality, poverty measures suffer from a selection bias: they do not count the missing poor (i.e., persons who would have been counted as poor provided they did not die prematurely). The Pre-Industrial period being characterized by an evolutionary advantage (i.e., a higher number of surviving children per household) of the non-poor over the poor, one may expect that the missing poor bias is substantial during that period. This paper quantifies the missing poor bias in Pre-Industrial societies, by computing the hypothetical headcount poverty rates that would have prevailed provided the non-poor did not benefit from an evolutionary advantage over the poor. Using data on Pre-Industrial England and France, we show that the sign and size of the missing poor bias are sensitive to the degree of downward social mobility.
Keywords Measurement, Selection effects, Missing poor, Poverty
Publication HAL Google Scholar
Abstract The objective of this study was to explore and describe the specificities of the occupational life of infertile endometriotic women treated by in vitro fertilization. We conducted a qualitative monocentric study between December 2020 and June 2021. Twelve semi-structured in-depth interviews using a theme-based interview guide with open questions were undertaken with infertile women with deep infiltrating endometriosis. Data analysis was conducted using an inductive approach according to the grounded theory method. Three main themes emerged from the interviews: (i) barriers to reconciling illness and work life, (ii) facilitating factors for well-being at work, and (iii) consequences and outlooks. It appeared that the time of infertility treatment represents a particular period of change in the working lives of women with endometriosis. For most women, these changes are experienced negatively, often with a renunciation of goals. For others, this is the time to communicate the difficulties linked to their illness to their professional entourage. There is a long path ahead to finally achieving recognition of endometriosis in the context of professional life.
Keywords Qualitative study, In vitro fertilization, Endometriosis
Publication HAL Google Scholar
Abstract The impact of US allocation of family planning aid on other donors is studied in order to gain new insights into donor interactions. Within this context, the dominant player in the sector is the United States, whose policies on family planning undergo changes influenced by domestic debates surrounding abortion. By utilizing the Mexico City Policy and considering exposure to this particular policy as an instrumental factor, it has been observed that other donors do not immediately react to policy changes made by the United States, either contemporaneously or within one year. However, a noticeable shift occurs after a two-year period, indicating that these donors eventually align their allocation strategies with those of the United States. Further analysis of this phenomenon reveals varying patterns among different types of donors. While smaller donors exhibit a clear intention to compensate for US policy changes, larger donors display a mix of competitive tendencies and herding behavior, thereby reinforcing the impact of the Mexico City Policy after the two-year time frame.
Keywords Family planning, Foreign aid, Mexico City Policy, Donor interaction
Publication HAL Google Scholar
Abstract In current economic conditions, financial stability is paramount to the proper functioning of open markets. Financial stability must be balanced with financial flexibility. This relationship is deeply affected by financial fragmentation. This is why Central Banks have focused on these issues in the last decade in particular. Both financial stability and financial fragmentation have unintended consequences on optimal currency areas. In this paper, we survey the original optimal currency areas literature and relate it with the new literature on financial stability and financial fragmentation. We highlight the importance of new macroprudential policies both at the national and regional levels.
Publication HAL Google Scholar
Abstract In 2020, Berlin introduced a rigorous rent-control policy responding to soaring prices by capping rents: the Mietendeckel (rent freeze). The German Constitutional Court revoked the policy only one year later. Although successful in lowering rents during its duration, the consequences for Berlin’s rental market and close-by markets are per se not clear. This article evaluates the short-term causal supply-side effects in terms of prices, quantities, and landlords’ strategic behavior. We develop a theoretical framework capturing the key features of first-generation rent control policies and Berlin-specific aspects. Using a rich pool of detailed rent advertisements, predictions are tested, and further empirical causal inference techniques are applied for comparing price trajectories of dwellings inside and outside the policy’s scope. Mechanically, advertised rents drop significantly upon the policy’s enactment. A substantial rent gap along Berlin’s administrative border emerges, and rapidly growing rents in Berlin’s (unregulated) adjacent municipalities are observed. Landlords started adopting a hedging strategy insuring themselves against the risk of contractually long-term fixed low rents following a potentially unconstitutional law. Whereas this hedge was beneficial for landlords, the risk was completely borne by tenants. Moreover, the number of available properties for rent dropped significantly, a share of which appears to be permanently lost for the rental sector. This hampers a successful housing search for first-time renters and people moving within the city. Overall, negative consequences for renters appear to outweigh positive ones.
Keywords Legal uncertainty, Supply disruptions, Urban policy, Rent freeze, First-generation rent control
Publication HAL Google Scholar
Abstract We build up a general purpose decision model to predict the choice between going to war and staying at peace for a rational decision-maker. This model articulates root causes such as the risk of future war and parameters such as potential gains in case of victory, potential losses in case of defeat, the probability of victory and the war human losses. We apply and calibrate this model to the case of German and French decision-makers at the very end of July 1914, taking into account the decisions already taken by Austria-Hungary and Russia and the uncertainty surrounding the decision of Great Britain. We assume a short war that does not last beyond 1914. Our model predicts the entry into the war of Germany and France, the argument of preventive war (going to war today rather than tomorrow) proving to be decisive for both countries, with the added benefit for France of the potential recovery of Alsace-Moselle in the event of victory. The computation reveals that of the two countries, it was France that seems to have the most interest in the war, making it possible to explain the passive behavior of the French leaders, Raymond Poincaré in the first place, who, if they did not provoke the war, did not really try to avoid it either.
Keywords WWI, Preventive war, Rational decision making, Raymond Poincaré, Bethmann-Hollweg, Guerre de 14-18, Guerre préventive, Modèle de décision rationnelle, Raymond Poincaré, Bethmann-Hollweg
Publication HAL Google Scholar
Abstract This paper uses a novel dataset on ethnic warfare to shed light on how conflict affects social identification and cohesion. A large body of anecdotal studies suggests that ethnic identities become more salient at times of conflict. Using data from eighteen sub-Saharan countries, I provide econometric evidence for such a claim. The effect of ethnic conflict on various measures of social cohesion is also investigated, uncovering a positive relationship between the two. The finding is understood as a result of the ethnocentric dynamics generated by conflict: as ethnic warfare increases ethnic identification, in-group cooperation follows suit. This parochial interpretation is further strengthened by the use of remote violence and the conditionality of conflict-induced pro-social behaviour on low levels of ethnic polarisation.
Keywords Africa, Identity, Social cohesion, Ethnic conflict
Publication HAL Google Scholar
Abstract In pharmaceutical studies, the Quality by Design (QbD) approach is increasingly being implemented to improve product development. Product quality is tested at each step of the manufacturing process, allowing a better process understanding and a better risk management, thus avoiding manufacturing defects. A key element of QbD is the construction of a Design Space (DS), i.e., a region in which the specifications on the output parameters should be met. Among the various possible construction methods, Designs of Experiments (DoE), and more precisely Response Surface Methodology, represent a perfectly adapted tool. The DS obtained may have any geometrical shape; consequently, the acceptable variation range of an input may depend on the value of other inputs. However, the experimenters would like to directly know the variation range of each input so that their variation domains are independent. In this context, we developed a method to determine the “Proven Acceptable Independent Range” (PAIR). It consists of looking for all the hyper polyhedra included in the multidimensional DS and selecting a hyper polyhedron according to various strategies. We will illustrate the performance of our method on different DoE cases.
Keywords Quality by Design QbD, Design of Experiments DoE, Response Surface Methodology RSM, Design Space DS, Proven Acceptable Independent Range PAIR
Publication HAL Google Scholar
Abstract With the low adherence to voluntary mutual health insurance, Senegal’s policymakers have sought to understand the feasibility of compulsory health insurance membership. This study aims to measure the acceptability of mandatory membership in community-based mutual health insurance (CBHI) and to understand its possible administrative modalities. The study consists of a national survey among a representative population sample selected by marginal quotas. The survey was conducted in 2022 over the phone, with a random composition method involving 914 people. The questionnaire measured the socio-economic characteristics of households, their level of acceptability concerning voluntary and compulsory membership, and their level of confidence in CBHIs and the health system. Respondents preferred voluntary (86%) over mandatory (70%) membership of a CBHI. The gap between voluntary and compulsory membership scores was smaller among women (p = 0.040), people under 35 (p = 0.033), and people with no health coverage (p = 0.011). Voluntary or compulsory membership was correlated (p = 0.000) to trust in current CBHIs and health systems. Lack of trust in the CBHI management has been more disadvantageous for acceptance of the mandatory than the voluntary membership. No particular preference emerged as the preferred administrative channel (e.g. death certificate, identity card, etc.) to enforce the mandatory option. The results confirmed the well-known challenges of building universal health coverage based on CBHIs—a poorly appreciated model whose low performance reduces the acceptability of populations to adhere to it, whether voluntary or mandatory. Suppose Senegal persists in its health insurance approach. In that case, it will be essential to strengthen the performance and funding of CBHIs, and to gain population trust to enable a mandatory or more systemic membership.
Publication HAL Google Scholar
Abstract Les îles seront-elles bientôt rayées de la carte, englouties par la montée des eaux ? Les plages de sable fin, les cocotiers, des Caraïbes au Pacifique glissent lentement sous la mer. Bientôt, ces paysages paradisiaques ne seront que de lointains souvenirs. Pour ceux qui y vivent, c’est toute leur vie qui prend l’eau. Selon les économistes L. Cassin, P. Melindi-Ghidi et F. Prieur, ces populations n’auront guère d’autres solutions que la migration.
Keywords Changement climatique, Ile
HAL Google Scholar
Abstract The sustainability of resource use and the management of public finances are both long‐run issues that are linked to each other through savings decisions. To study them conjointly, this paper introduces a public debt stabilization constraint in an overlapping generation model in which nonrenewable resources constitute a necessary input in the production function and belong to agents. It shows that stabilization of public debt at a high level (as share of capital) may prevent the existence of a sustainable development path, that is, a path on which per capita consumption is not decreasing. Public debt thus appears as a threat to sustainable development. It also shows that higher public debt‐to‐capital ratios (and public expenditures‐to‐capital ones) are associated with lower growth. Two transmission channels are identified. As usual, public debt crowds out capital accumulation. In addition, public debt tends to increase resource use which reduces the rate of growth. We also provide a numerical analysis of the dynamics that shows that the economy is characterized by saddle path stability. Finally, we show that the public debt‐to‐capital ratio may be calibrated to implement the social planner optimal allocation according to which the growth rate is increasing in the degree of patience.
Publication HAL Google Scholar
Abstract The current health crisis has particularly affected the elderly population. Nursing homes have unfortunately experienced a relatively large number of deaths. On the basis of this observation and working with European data (from SHARE), we want to check whether nursing homes were lending themselves to excess mortality even before the pandemic. Controlling for a number of important characteristics of the elderly population in and outside nursing homes, we conjecture that the difference in mortality between those two samples is to be attributed to the way nursing homes are designed and organized. Using matching methods, we observe excess mortality in Sweden, Belgium, Germany, Switzerland, Czech Republic and Estonia but not in the Netherlands, Denmark, Austria, France, Luxembourg, Italy and Spain. This raises the question of the organization and management of these nursing homes, but also of their design and financing.
Keywords Mortality, Nursing homes, Propensity score matching, SHARE
Publication HAL Google Scholar
Abstract Purpose Although the solid empirical proof of momentum is documented in various stock markets, there are many debates among academics with respect to the source of momentum profit. The first aim of this paper is intensively re-examine the momentum profit in Vietnam, an important emerging market. Secondly, the authors study the return predictability of a measure of investors’ overreaction, then examine whether the momentum effect in Vietnam is explained by overreaction. Design/methodology/approach Using the weekly data of more than 300 non-financial Vietnamese stocks during 2009–2019, the authors build a measure of investors’ overreaction, which is based on trading volume and the sign of stock returns. Consequently, to investigate whether momentum exits after controlling for overreaction, the authors carefully compare trading strategies based on overreaction with price momentum strategies using adjusted returns and double sorts on past returns and levels of overreaction. Findings The article makes three main findings. Firstly, the authors discover the empirical evidence of momentum in the Vietnamese equity market. Secondly, the measure of overreaction could be a predictor of Vietnamese stock returns. Stocks that have experienced a stronger upward overreaction provide a higher average return. Finally, returns on trading strategies based on overreaction are robust after adjusting for momentum, while returns on momentum portfolios become insignificant after adjusting for overreaction. By double-sorting, the authors document that holding past returns constant, the average returns of portfolios rise monotonically with their measure of overreaction. Hence, the momentum profit in Vietnam arises from investors’ overreaction. Originality/value The paper extends previous research on the behavioral explanation of momentum in emerging stock markets, which has not been fully exploited in the literature.
Keywords Momentum, Overreaction, Overconfident investors, Stock returns, Trading strategy
Publication HAL Google Scholar
Abstract We analyze the effects of a debt relief, that is, a decrease in public debt of a low-income country financed by a high-income country, on environmental quality. Under perfect mobility of assets, the debt relief increases the overall capital stock, and environmental quality when public abatements are sufficiently efficient. Welfare in both countries can also improve. Under a weak mobility of assets, capital does no more increase in the richest country, but environmental quality can improve. This comes from a crowding-out effect of debt in the high-income country, which does no more take place when the mobility of assets is significant.
Keywords Capital market integration, Global pollution, Overlappinggenerations, Public debt, Overlapping generations
Publication HAL Google Scholar
Abstract Using data on roughly half a million cases and 10,000 judges from Pakistan and India, Mehmood et al. estimate the impact of the Ramadan fasting ritual on criminal sentencing decisions. They find that fasting increases judicial leniency and reduces reversals of decisions in higher courts. We estimate the impact of the Ramadan fasting ritual on criminal sentencing decisions in Pakistan and India from half a century of daily data. We use random case assignment and exogenous variation in fasting intensity during Ramadan due to the rotating Islamic calendar and the geographical latitude of the district courts to document the large effects of Ramadan fasting on decision-making. Our sample comprises roughly a half million cases and 10,000 judges from Pakistan and India. Ritual intensity increases Muslim judges' acquittal rates, lowers their appeal and reversal rates, and does not come at the cost of increased recidivism or heightened outgroup bias. Overall, our results indicate that the Ramadan fasting ritual followed by a billion Muslims worldwide induces more lenient decisions.
Keywords Religious rituals, Ramadan, Decision-making, Religious rituals Ramadan decision-making, Religious rituals
Publication HAL Google Scholar
Abstract In this paper, we provide systematic evidence of how historical religious institutions affect the rule of law. In a difference-in-differences framework, we show that districts in Pakistan where the historical presence of religious institutions is higher, rule of law is worse. This deterioration is economically significant, persistent, and likely explained by religious leaders gaining political office. We explain these findings with a model where religious leaders leverage their high legitimacy to run for office and subvert the Courts. We test for and find no evidence supporting several competing explanations: the rise of secular wealthy landowners, dynastic political leaders and changes in voter attitudes are unable to account for the patterns in the data. Our estimates indicate that religious leaders expropriate rents through the legal system amounting to about 0.06 percent of GDP every year.
Publication HAL Google Scholar
Abstract This paper has two parts. The mathematical part provides generalized versions of the robust Ekeland variational principle in terms of set-valued EVP with variable preferences, uncertain parameters and changing weights given to vectorial perturbation functions. The behavioural part that motivates our findings models the formation and stability of a partnership in a changing, uncertain and complex environment in the context of the variational rationality approach of stop, continue and go human dynamics. Our generalizations allow us to consider two very important psychological effects relative to ego depletion and goal gradient hypothesis.
Keywords Variational rationality, Variable preferences, Ego depletion, Goal gradient hypothesis, Robust Ekeland variational principle
Publication HAL Google Scholar