Publications

Résumé BackgroundMany studies have investigated early predictors for Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). However, evidence is sparse regarding specific and common predictors for these diseases. We aimed to identify medication use, health conditions, and blood biomarkers that might be associated with the risk of AD, PD, and ALS ten years later. MethodsWe conducted population-based nested case-control studies of AD, PD, and ALS using electronic medical records in Europe (France, the UK, and Sweden) and Australia. We retrieved data on medication use, diagnosed health conditions, and measured blood biomarkers from electronic medical records or biomedical cohorts. Conditional logistic regression models and meta-analysis were applied to assess the associations between these prodromal factors and the risk of receiving a diagnosis of AD, PD, or ALS. FindingsWe included a total of 149,642 AD cases (mean age: 79.1-81.2 years), 252,696 PD cases (73.2-75.9 years), and 27,533 ALS cases (64.4-69.6 years). The prescription of psychoanaleptics and nasal preparations was consistently associated with an increased risk of AD, PD, and ALS 5-10 years later. Constipation and use of related medications were associated with an increased risk of AD and PD, while diabetes and use of antidiabetics were associated with a reduced risk of ALS. A higher level of triglycerides was associated with a lower risk of AD, whereas a higher level of Apolipoprotein B was associated with a lower risk of PD, 5-10 years later. InterpretationPsychoanaleptics and nasal preparations may serve as common predictors for diagnosis of AD, PD, and ALS 5-10 years later. Conversely, the increased prevalence of constipation is specific to AD and PD, while the decreased prevalence of diabetes and use of antidiabetics are specific to ALS. FundingEU Joint Programme -Neurodegenerative Disease Research.
Mots clés Neurodegenerative disease, Alzheimer&#039, s disease, Parkinson&#039, s disease, Amyotrophic lateral sclerosis, Medications, Health conditions, Biomarkers
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Résumé In this article, we introduce the command beyondpareto , which estimates the extreme-value index for distributions that are Pareto-like, that is, whose upper tails are regularly varying and eventually become Pareto. The estimation is based on rank-size regressions, and the threshold value for the upper-order statistics included in the final regression is determined optimally by minimizing the asymptotic mean squared error. An essential diagnostic tool for evaluating the fit of the estimated extrerme-value index is the Pareto quantile–quantile plot, provided in the accompanying command pqqplot . The usefulness of our estimation approach is illustrated in several real-world examples focusing on the upper tail of German wealth and city-size distributions.
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Résumé Introduction: Expanding health insurance is viewed as a core strategy for achieving universal health coverage. In Senegal, as in many other developing countries, this strategy has been implemented by creating community-based health insurance (CBHI) schemes with voluntary enrolment and a fixed premium paid by enrollees. Yet little is known about how the individuals’ experience of CBHI enrolment further influences their willingness to pay (WTP). In this paper, we test the existence of a reinforcement effect between effective enrolment in a CBHI and WTP for health insurance by analysing their mutual relationship. Methods: We rely on primary survey data collected in 2019–2020 in the rural area of Niakhar in Senegal. We use an econometric methodology involving: (1) Heckman-type selection models to estimate the determinants of CBHI membership conditioned on awareness of health insurance, addressing the issue of sample selection due to differential awareness and (2) a simultaneous equation model to jointly estimate the uptake and WTP for health insurance, addressing the issue of endogeneity due to reverse causality between both variables. We also focus on the roles that informational and geographical barriers, as well as individual risk preference and trust, play in both outcomes. Results: The final sample includes 1607 individuals. Results show that WTP further increases with the individuals’ direct experience in a CBHI scheme, despite an environment characterised by low enrolment rates. We also provide evidence for a U‐shaped relationship between risk tolerance and WTP for health insurance. Conclusion: We provide novel evidence on a reinforcement effect of enrolment in a CBHI on WTP for health insurance, with the presence of a substantial consumer surplus among enrolled individuals at the actual premium. Our findings suggest that policies aiming at improving health insurance awareness should foster the demand for health insurance in rural Senegal.
Mots clés Sub-Saharan Africa, Senegal, Rural population, Rural health, Information, Willingness to pay, Uptake, Community-based health insurance, Health insurance
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Résumé We propose a non parametric hypothesis test to compare two partitions of a same data set. The partitions may result from two different clustering approaches. The test may be done using any comparison index but we focus in particular on the Matching Error (ME) that is related to the misclassification error in supervised learning. Some properties of the ME and, especially, its distribution function for the case of two different partitions are analyzed. Extensive simulations and experiments show the efficiency of the test.
Mots clés Clustering, Comparing partitions, Hyposthesis test, Matching error
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Résumé This paper evaluates the importance of access to justice (ATJ) for economic growth. To do so, we create a new database on the number of judges per capita by collecting data from various public institutions and academic publications. We use these data as a country-level indicator to capture the structural evolution of ATJ from 1970 to 2019 for a wide range of developed and developing countries. Using an instrumental variable approach in a dynamic panel setting to deal with endogeneity, we show that ATJ has a sizable positive effect on economic growth. The substantial aggregate effect of ATJ on growth is independent of countries' legal origin, customary law, rule of law or level of democracy. However, we find evidence that the economic returns from ATJ are higher in poorer countries. In terms of mechanisms, our results suggest that ATJ promotes growth via higher government accountability and improved institutional quality.''Promote peaceful and inclusive societies for sustainable development, provide access to justice for all and build effective, accountable and inclusive institutions at all levels'' [Sustainable Development Goal 16 (United Nations, 2015)] ✩ We would like to thank the editor, Evi Pappa, several anonymous referees, as well as Alexia Autenne,
Mots clés Access to justice, Economic Growth, Institutions, Judges, Access to justice Economic growth Institutions Judges
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Résumé When can exogenous changes in beliefs generate endogenous fluctuations in rationalexpectation models? We analyze this question in the canonical one-sector and two-sector models of the business cycle with increasing returns to scale. A key feature of ouranalysis is that we express the uniqueness/multiplicity condition of equilibirum pathsin terms of restrictions on five critical and economically interpretable parameters: theFrisch elasticities of the labor supply curve with respect to the real wage and to themarginal utility of wealth, the intertemporal elasticity of substitution in consumption,the elasticity of substitution between capital and labor, and the degree of increasingreturns to scale. We obtain two clear-cut conclusions: belief-driven fluctuations cannotexist in the one-sector version of the model for empirically consistent values for thesefive parameters. By contrast, belief-driven fluctuations are a robust property of thetwo-sector version of the model—with differentiated consumption and investmentgoods—, as they now emerge for a wide range of parameter values consistent withavailable empirical estimates. The key ingredients explaining these different outcomesare factor reallocation between sectors and the implied variations in the relative priceof investment, affecting the expected return on capital accumulation.
Mots clés Income effect, Expectations, Endogenous fluctuations, Belief-driven business cycles
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Résumé Firm entry and capital investment both vary over the business cycle. This paper analyzes the role of the firm entry delay option (waiting option) in the joint dynamics of firm entry and investment in a news-driven RBC model. We introduce the waiting option by restricting the number of potential firm entrants and demonstrate that the combination of news shocks and the waiting option effect yields empirically plausible joint dynamics of firm entry and investment over the business cycle. In contrast, the model without the entry delay option produces excessively volatile firm entry. We rationalize our findings using an analytical real-option model of firm entry.
Mots clés Entry delay option, Firm entry, News shocks, Real business cycle
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Résumé We study reputation dynamics within the household in a setting where women regularly receive transfers from their husbands for household purchases. We propose a signaling model in which wives try to maintain a good reputation in the eyes of their husbands to receive high transfers. This leads them to (i) avoid risky purchases (goods with unknown returns) and (ii) knowingly overuse low-return goods to hide bad purchase decisions—we call this the intrahousehold sunk cost effect. We present supportive evidence for the model from a series of experiments with married couples in rural Malawi.
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Résumé In this paper, we examine the quasi-equilibrium problem from a variational rationality perspective. To this end, we first study the convergence of the proximal point method proposed by Bento et al. [Ann. Oper. Res. 316 (2022), 1301-1318] in the more general context of quasi-equilibrium problems using a Bregman distance. Thus, we provide an application of the method through a recent behavioral perspective, more precisely, the variational rationality approach of staying and changing human dynamics, and the important example of climbing the goal ladder in goal pursuit theory. An illustrative simulation demonstrates that Bregman distances improve the computational performance of the method compared to the Euclidean distance.
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Résumé This paper introduces a novel mechanism driving endogenous business cycle fluctuations within a frictionless three-sector intertemporal equilibrium model. We emphasize the critical role of consumer preferences as a primary driver of cyclical dynamics by considering a consumption bundle composed of a pure consumption good and a mixed consumption-investment good that simultaneously serves as both a final consumption good and a capital-accumulating investment good. Endogenous fluctuations naturally arise from sectoral capital intensity differences, an intertemporal consumption trade-off between the two goods, or the interaction of both mechanisms. We offer a detailed characterization of the economy's dynamics, identifying the Hopf bifurcation conditions that trigger persistent cyclical behavior. Additionally, we explore the periodicity of the resulting limit cycles, providing insights into how shifts in preferences and sectoral complementarities can generate self-sustained macroeconomic fluctuations.
Mots clés Three-sector intertemporal equilibrium growth models, Business cycles fluctuations, Hopf bifurcation, Endogenous cycle, Periodicity
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Résumé Clustering is widely used in unsupervised learning to fnd homogeneous groups of observations within a dataset. However, clustering mixed-type data remains a challenge, as few existing approaches are suited for this task. Tis study presents the state-of-the-art of these approaches and compares them using various simulation models. Te compared methods include the distance-based approaches k-prototypes, PDQ, and convex k-means, and the probabilistic methods KAy-means for MIxed LArge data (KAMILA), the mixture of Bayesian networks (MBNs), and latent class model (LCM). Te aim is to provide insights into the behavior of diferent methods across a wide range of scenarios by varying some experimental factors such as the number of clusters, cluster overlap, sample size, dimension, proportion of continuous variables in the dataset, and clusters' distribution. Te degree of cluster overlap and the proportion of continuous variables in the dataset and the sample size have a signifcant impact on the observed performances. When strong interactions exist between variables alongside an explicit dependence on cluster membership, none of the evaluated methods demonstrated satisfactory performance. In our experiments KAMILA, LCM, and k-prototypes exhibited the best performance, with respect to the adjusted rand index (ARI). All the methods are available in R.
Mots clés Bayesian networks, Clustering, KAMILA, LCM, Mixed-type data
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Résumé Earnings are often top-coded (right-censored) in administrative registers. The censoring threshold in the case of Germany is the limit value for social security contributions, leading to a substantial fraction of censoring: For example, about 12 % of male workers in West Germany are affected, rising to above 30 % for highly educated prime-aged workers. This missing right tail of the earnings distribution constitutes a major problem for researchers studying earnings inequality and top incomes. We overcome this challenge by taking a distributional approach and semi-parametrically modelling the right tail as being Pareto-like. Non-censored earnings survey data matched to administrative records, derived from the SOEP-RV project, let us operate in a laboratory-like setting in which the targets are known. Our approach outperforms alternative imputation methods based on Tobit regressions.
Mots clés Right-censored earnings, Top-coding, SOEP-RV, Heavy-Tailed Distribution, Extreme value index, Imputation
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Résumé For standard inequality measures, distribution-free inference methods are valid under conventional assumptions that fail to hold in applications. Resulting Bahadur-Savage type failures are documented, and correction methods are provided. Proposed solutions leverage on the positive support prior that can be defended with economic data such as income, in which case directional non-parametric tests can be salvaged. Simulation analysis with generalized entropy measures allowing for heavy tails and contamination reveals that proposed lower confidence bounds provide concrete size and power improvements, particularly through bootstraps. Empirical analysis on within-country wage inequality and on world income inequality illustrates the usefulness of the proposed lower bound, as opposed to the erratic behavior of traditional upper bounds.
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Résumé Chacun peut être amené au cours de sa vie à s’intéresser à l’histoire pour saisir les enjeux d’un affrontement entre groupes sociaux ou mieux appréhender comment les doctrines naissent et disparaissent. L’économie, de son côté, est devenue omniprésente. On écoute aujourd’hui les économistes comme les Grecs et les Romains écoutaient les oracles. L’histoire et l’économie sont donc des disciplines incontournables. Dans ces temps troublés, on aimerait que ces deux disciplines, aux méthodes parfois antagonistes, associent leurs génies respectifs, l’histoire offrant la perspective du temps long, l’économie offrant la panoplie la plus actuelle de méthodes quantitatives.
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Résumé This paper focuses on the welfare effects of domestic and international lobbying in the context of two countries linked by both trade and pollution. We consider a reciprocal-markets model where, in each country, a domestic firm produces a polluting good, that can result in a cross-national environmental externality, and competes in quantities in each market with a foreign firm. Each government independently sets a pollution tax under political pressure from green and industrial lobbies à la Grossman and Helpman (1994). Our results mainly show that political pressure from domestic and/or international lobbies can help mitigate tax competition between the two countries, resulting in an improvement in social welfare. In fact, lobbying acts much like a strategic delegation device by changing the social welfare weights in the objective function of each government. The (potential) welfare-improving effect of political pressure depends on the relative strengths of the lobbies and on the nature of the strategic interactions in taxes.
Mots clés Lobbying, Transboundary pollution, International trade, International politics, Environmental tax
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Résumé C’est la version économique de la quadrature du cercle : comment à la fois investir massivement pour la transition écologique et maîtriser la dette pour retrouver des marges de manœuvre financières ? Sous certaines conditions, les deux sont possibles simultanément. Découvrez comment.
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Résumé As countries develop and experience structural transformation, the gendered patterns of labor change. We use harmonized labor force data and do not find evidence that women's share of the agricultural labor force is positively correlated with per capita income. Yet, the evidence shows many changes taking place that vary across locations. We identify five areas that require attention to understand these processes of change: the patterns of joint ownership and management among smallholder farmers, the responses to the migration of men off‐farm, shifts across sectoral boundaries, time spent on domestic services and care work, and the impact on empowerment. It is important to go beyond the number of people employed in production agriculture to understand the many ways that the gendered patterns of labor are changing.
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Résumé In this paper, we examine rebalancing strategies for long-term institutional investors. Specifically, we test the difference in risk-adjusted performance between stock-bond portfolios based on buy-and-hold, periodic and threshold rebalancing strategies. Using the Norwegian Sovereign Wealth Fund (SWF) as a benchmark and an econometric approach based on a bootstrap test of Sharpe ratio differences, we show that the optimal rebalancing differs across economic and financial cycles. Furthermore, we find that the optimal strategy is periodic rebalancing except during recessions and crises when the buy-and-hold approach is best, thus calling into question the hypothesis of the countercyclical behaviour of SWFs. Our results are robust to alternative performance measures, asset allocations, investment horizons, rebalancing rules, nonnormal and noniid returns, transaction costs and time sampling. Finally, our findings promote the consideration of macroprudential rules to improve the Santiago Principles and a specific monitoring framework targeted at SWFs.
Mots clés Financial stability, Boobstrap test, Institutional investors, Portfolio rebalancing
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