Publications

Abstract We study whether fiscal policies, especially public debt, can help to curb the macroeconomic and health consequences of epidemics. Our approach is based on three main features: we introduce the dynamics of epidemics in an overlapping generations model to take into account that old people are more vulnerable; people are more easily infected when pollution is high; public spending in health care and public debt can be used to tackle the effects of epidemics. We show that fiscal policies can promote convergence to a stable disease-free steady state. When public policies are not able to permanently eradicate the epidemic, public debt, and income transfers could reduce the number of infected people and increase capital and GDP per capita. As a prerequisite, pollution intensity should not be too high. Finally, we define a household subsidy policy that eliminates income and welfare inequalities between healthy and infected individuals.
Keywords Epidemics, Pollution, Overlapping generations, Public debt
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Abstract Objectifs : Cette étude vise à établir un état des lieux de l’enseignement de l’Éducation Thérapeutique du Patient (ETP) en formation initiale des sages-femmes françaises. Méthode : Une étude quantitative descriptive a été menée sur le territoire français. Un questionnaire en ligne, comportant 27 questions a été diffusé aux 35 écoles de sages-femmes françaises. Résultats : Sur 19 écoles ayant répondu à l’enquête, 11 enseignaient l’ETP, 8 ne l’abordaient pas en formation. Cet enseignement est principalement transversal. Les freins à l’enseignement de l’ETP sont la densité actuelle du programme, l’absence de texte réglementant cet enseignement et des difficultés à circonscrire le champ de l’ETP par rapport à celui de la prévention, de la promotion et de l’éducation pour la santé. La simulation est utilisée dans une seule école. Discussion : Cette enquête montre une volonté des équipes pédagogiques à investir dans l’enseignement des éducations en santé, notamment de l’ETP. Pour cela, il s’agit de renforcer la formation des enseignants afin de clarifier les domaines d’intervention de la sage-femme faisant appel à la promotion de la santé, la prévention et les éducations en santé ; de proposer des stages spécifiques aux étudiants et de faire appel à la simulation. L’allongement de la durée de la formation initiale constitue une opportunité de planifier un enseignement spécifique et de discuter la place du service sanitaire.
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Abstract Despite their high predictive performance, random forest and gradient boosting are often considered as black boxes which has raised concerns from practitioners and regulators. As an alternative, we suggest using partial linear models that are inherently interpretable. Specifically, we propose to combine parametric and non‐parametric functions to accurately capture linearities and non‐linearities prevailing between dependent and explanatory variables, and a variable selection procedure to control for overfitting issues. Estimation relies on a two‐step procedure building upon the double residual method. We illustrate the predictive performance and interpretability of our approach on a regression problem.
Keywords Machine leaning, Lasso, Autometrics, GAM
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Abstract This paper studies the behavioral and socio-demographic determinants of reported compliance with prophylactic measures against COVID-19: barrier gestures, lockdown restrictions and mask wearing. The study contrasts two types of measures for behavioral determinants: experimentally elicited preferences (risk tolerance, time preferences, social value orientation and cooperativeness) and stated preferences (risk tolerance, time preferences, and the GSS trust question). Data were collected from a representative sample of the metropolitan French adult population (N=1154) surveyed during the first lockdown in May 2020, and the experimental tasks were carried out on-line. The in-sample and out-of-sample predictive power of several regression models - which vary in the set of variables that they include - are studied and compared. Overall, we find that stated preferences are better predictors of compliance with these prophylactic measures than preferences elicited through incentivized experiments: self-reported level of risk, patience and trust are predicting compliance, while elicited measures of risk-aversion, patience, cooperation and prosociality did not.
Keywords COVID-19, Individual preferences, Social preferences, Elicited preferences, Stated preferences
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Abstract Plain English Summary Corruption and regulation can have ambiguous relationships with entrepreneurship unless you take a careful look at it. We examine the impact of corruption and entry-regulation on opportunity and necessity-motivated entrepreneurship within different economic development contexts. Corruption and entry-regulation correlate negatively with entrepreneurship but might have a tempering effect on each other. Thus, we consider whether corruption reduces the negative impact of entry-regulation on entrepreneurship while remaining globally negative (i.e., the “weak view”) or if it completely counterbalance the negative effect (the “strong view”). Exploiting a cross-country dataset on 105 countries over the 2003–2016 period, we find that, while corruption might somewhat temper the negative impact of a heavy administrative machinery in developing countries, this tempering effect of corruption will generally be non-significant. Furthermore, our findings suggest that corruption deters opportunity-motivated entrepreneurship—the type of entrepreneurship that may contribute the most to productivity, economic growth and development. Corruption and regulation would then be particularly harmful for economic development. The policy-maker tackling these issues would do well to consider direct effects and possible interrelationships according to context.
Keywords Entreprenarial motives, Necessity, Opportunity, Sand the wheels, Grease the wheels, Doing business, Régulation, Corruption, Entrepreneurship
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Abstract Objective This study aims to develop high-performing Machine Learning and Deep Learning models in predicting hospital length of stay (LOS) while enhancing interpretability. We compare performance and interpretability of models trained only on structured tabular data with models trained only on unstructured clinical text data, and on mixed data. Methods The structured data was used to train fourteen classical Machine Learning models including advanced ensemble trees, neural networks and k-nearest neighbors. The unstructured data was used to fine-tune a pre-trained Bio Clinical BERT Transformer Deep Learning model. The structured and unstructured data were then merged into a tabular dataset after vectorization of the clinical text and a dimensional reduction through Latent Dirichlet Allocation. The study used the free and publicly available Medical Information Mart for Intensive Care (MIMIC) III database, on the open AutoML Library AutoGluon. Performance is evaluated with respect to two types of random classifiers, used as baselines. Results The best model from structured data demonstrates high performance (ROC AUC = 0.944, PRC AUC = 0.655) with limited interpretability, where the most important predictors of prolonged LOS are the level of blood urea nitrogen and of platelets. The Transformer model displays a good but lower performance (ROC AUC = 0.842, PRC AUC = 0.375) with a richer array of interpretability by providing more specific in-hospital factors including procedures, conditions, and medical history. The best model trained on mixed data satisfies both a high level of performance (ROC AUC = 0.963, PRC AUC = 0.746) and a much larger scope in interpretability including pathologies of the intestine, the colon, and the blood; infectious diseases, respiratory problems, procedures involving sedation and intubation, and vascular surgery. Conclusions Our results outperform most of the state-of-the-art models in LOS prediction both in terms of performance and of interpretability. Data fusion between structured and unstructured text data may significantly improve performance and interpretability.
Keywords Clinical transformers, Structured and unstructured data, Data fusion, Explainable AI, Hospital length of stay
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Abstract We study a class of location games where players want to attract as many resources as possible and pay a cost when deviating from an exogenous reference location. This class of games includes political competitions between policy-interested parties and firms' costly horizontal differentiation. We find that the introduction of reference locations simplifies the set of pure-strategy equilibrium to a unique candidate which has a strong property: at most four players, the two most-left and two most-right, deviate from their reference locations. We provide necessary and sufficient conditions for the candidate to be an equilibrium. We illustrate our results in particular cases including the duopoly competition where we moderate the principle of minimal differentiation.
Keywords Location games Spatial competition Spatial voting theory Costly product differentiation
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Abstract This paper has two parts. In the mathematical part, we present two inexact versions of the proximal point method for solving quasi-equilibrium problems (QEP) in Hilbert spaces. Under mild assumptions, we prove that the methods find a solution to the quasi-equilibrium problem with an approximated computation of each iteration or using a perturbation of the regularized bifunction. In the behavioral part, we justify the choice of the new perturbation, with the help of the main example that drives quasi-equilibrium problems: the Cournot duopoly model, which founded game theory. This requires to exhibit a new QEP reformulation of the Cournot model that will appear more intuitive and rigorous. It leads directly to the formulation of our perturbation function. Some numerical experiments show the performance of the proposed methods.
Keywords Quasi-equilibrium problem, Proximal point method, Inexact version, Monotone bifunction, Cournot duopoly, Moving constraints
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Abstract Introduction There is a lack of quantitative evidence on the role of food innovations—new food ingredients and processing techniques—in the nutrition transition. Objective Document the distribution of food innovations across 67 high-income (HIC) and middle-income (MIC) countries between 1970 and 2010, and its association with the nutritional composition of food supply. Methods We used all available data on food patents, as compiled by the European Patent Office, to measure food innovations. We considered innovations directly received by countries from inventors seeking protection in their territories, and those embedded in processed food imports. Food and Agricultural Organization data were used to estimate the associations between international diffusion of food innovations and trends in total food supply and its macronutrient composition, after adjusting for confounding trends in demand-side factors. We identified the role of trade by simulating the changes in average diet due to innovations embedded in food imports. Results Trends in food innovations were positively and significantly associated with changes in daily per capita calorie supply available for human consumption in MIC between 1990 and 2010 (elasticity of 0.027, 95% CI 0.019 to 0.036). Food innovations were positively correlated with the share of animal and free fats in total food supply (elasticities of 0.044, 95% CI 0.030 to 0.058 for MIC between 1970 and 1989 and 0.023, 95% CI 0.003 to 0.043 for HIC between 1990 and 2010). Food innovations were associated with substitutions from complex carbohydrates towards sugars in total food supply for MIC after 1990 (elasticities of −0.037, 95% CI −0.045 to −0.029 for complex carbs, 0.082, 95% CI 0.066 to 0.098 for sugars). For these countries, the trade channel capturing access to innovations through imports of processed food played a key role. Conclusion Policy-makers should consider the impacts of the international diffusion of food innovations in assessing the costs and benefits of international trade regulations.
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Abstract The increase in employment polarization observed in several high-income economies has coincided with a reduction in inter-generational mobility. This paper argues that the disappearance of middling jobs can drive changes in mobility, notably by removing a stepping stone towards high-paying occupations for those from less well-off family backgrounds. Using data from two British cohorts who entered the labour market at two points in time with very different degrees of employment polarization, we examine how parental income affects both entry occupations and occupational upgrading over careers. We find that transitions across occupations are key to mobility and that the impact of parental income has grown over time. At regional level, using a shiftshare IV-strategy, we show that the impact of parental income has increased the most in regions experiencing the greatest increase in polarisation. This indicates that the disappearance of middling jobs played a role in the observed decline in mobility.
Keywords British cohort, Parental income, Occupational transition, Job polarization, Inter-generational mobility
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Abstract The expansion of digital financial services leads to severe consumer protection issues such as fraud and scams. As these potentially decrease trust in digital services, especially in developing countries, avoiding victimization has become an important policy objective. In an online experiment, we first investigate how well individuals in Kenya identify phone scams using a novel measure of scam identification ability. We then test the effectiveness of scam education, a commonly used approach by organizations for fraud prevention. We find that common tips on how to spot scams do not significantly improve individuals’ scam identification ability, i.e., the distinction between scams and genuine messages. This null effect is driven by an increase in correctly identified scams and a decrease in correctly identified genuine messages, indicating overcaution. Additionally, we find suggestive evidence that genuine messages with scam-like features are misclassified more often, highlighting the importance of a careful design of official communication.
Keywords Consumer protection, Consumer fraud, Digital financial services, Scam susceptibility, Scam education, Kenya
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Abstract We revisit the question of colonial legacies in education by focusing on quality rather than quantity. We study Cameroon, a country where a Francophone education system with French colonial origins coexists with an Anglophone system with British colonial origins. This allows us to investigate the impact of different teaching practices on students' test scores. We find that pupils schooled in the Francophone system perform better in mathematics in Grade 5, with test scores higher by two thirds of a standard deviation. Thanks to detailed school survey data, we are able to account for a wide array of inputs of the education production function, such as the economic and social conditions of students, the material conditions of the schools and classrooms, as well as some information on the teachers' practices and pedagogical culture. We find that Francophone schools have better classroom equipment and that Francophone teachers use more vertical teaching methods, but that these differences cannot explain why Francophone students perform better in mathematics. In the end, we cannot pin down the exact mechanism behind our result.
Keywords Africa, Colonial legacies, School quality, Education
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Abstract We examine the links between age, risk tolerance, and impatience in a large French representative sample. We combine elicited preferences data based on an incentivized web experiment and stated preferences data based on self-reported surveys. Our findings highlight distinct patterns: when considering stated preferences, both risk tolerance and impatience exhibit a decline with age. Higher risk tolerance is associated with higher impatience, and this relationship strengthens with age in the financial domain. In contrast, our analysis of elicited measures uncovers a different dynamic. Specifically, risk tolerance tends to increase with age, while age exhibits no significant influence on impatience. Furthermore, individuals endowed with higher risk tolerance tend to demonstrate lower levels of impatience, irrespective of their age.
Keywords Time preferences, Stated preferences, Risk preferences, Elicited preferences, Age
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Abstract Based on a unique database (data on 2529 bank-firm relationships of 403 firms from 2012 to 2018) provided by the Central Bank of Tunisia, this article analyses the impact of the intensity and duration of bank-firm relationship on loan quality. By estimating a panel ordered probit model, the results show that the intensity of the lending relationship has a positive (negative) impact on high (medium or low) quality loans. In addition, the duration of the bank-firm relationship increases the probability of low-quality loans. We also find that the impact of relationship lending on loan quality differs according to the level of profitability of the firm. Low and non-performing firms tend to have longer and closer bank relationship, whereas it is the opposite for performing firms. Our results suggest that in an emerging market concentrated around a few banks, longer and closer banking relationships are mainly in favour of low and non-performing firms, reflecting adverse selection and strong moral hazard.
Keywords Banks, Relationship lending, Credit registry, Tunisia
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Abstract 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, evidence suggests that results are driven by behavioural explanations such as cross-gender differences in candidates' attitudes toward competition, or by political parties behaving differently toward female and male candidates for a given electoral outcome. 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.
Keywords Elections, Self-selection, Candidates, Persistence, Competition, Gender
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Abstract We rationalize the observed short-run differences in corporate and long-term government bond yields in an financial-accelerator model with frictions that restrict changes in portfolio shares. We estimate the model on quarterly data for the Euro Area from 1999 to 2019, and show that the portfolio friction parameter is positive and significant. Portfolio frictions not only generate a time-varying wedge between the two returns that fits the data, but also raise the volatility of return differentials, and the precautionary motive of savers. As a result, the macroeconomic effects of uncertainty shocks are amplified by portfolio frictions.
Keywords Uncertainty shocks, Portfolio frictions, Financial Accelerator
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Abstract In this paper, we provide a better understanding of what drives sovereign wealth funds (SWFs) to improve their governance. Using the most recent SWF governance scoreboard from Maire et al. (2021), we estimate a fractional response model to determine whether SWF governance disclosure norms are driven by the search for internal or external legitimacy. Overall, we find that SWFs have better governance when they originate from democratic countries with high-quality, national governance. Our results also show that SWFs tend to have better gover-nance quality when they need to acquire external legitimacy vis-à-vis the target company and its government. In particular, we find that SWFs have an incentive to improve their governance when they are sufficiently inter-nationalized, when the amount of foreign assets invested abroad is sufficiently large or when the amount of shares acquired in developed countries is significant. These findings demonstrate how SWFs may proactively build legitimacy in host countries when they need to adapt their foreign entry strategies. Our results have important implications for understanding the determinants of SWF governance in general.
Keywords Transparency, Internationalization, Governance, Sovereign Wealth Funds
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Abstract We use a distinctive methodology that leverages a fixed population of Twitter users located in France to gauge the mental health effects of repeated lockdown orders. To do so, we derive from our population a mental health indicator that measures the frequency of words expressing anger, anxiety and sadness. Our indicator did not reveal a statistically significant mental health response during the first lockdown, while the second lockdown triggered a sharp and persistent deterioration in all three emotions. Our estimates also show a more severe deterioration in mental health among women and younger users during the second lockdown. These results suggest that successive stay-at-home orders significantly worsen mental health across a large segment of the population. We also show that individuals who are closer to their social network were partially protected by this network during the first lockdown, but were no longer protected during the second, demonstrating the gravity of successive lockdowns for mental health.
Keywords Mental health, Twitter data, Well-being, Lockdown, COVID-19
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Abstract Purpose: The article examines stock index price responses in Brazil, Chile, and Mexico to those in the US, Spain, and four European countries during three sub-periods surrounding the neoliberal reforms of the 1990s: 1988 to 1994, 1995 to 1998, and 1999 to 2004. Design/methodology/approach: The methodology is empirical and uses time series analysis, in particular impulse response functions (IRFs) derived using vector autoregression (VAR) models. Main Findings: It finds that equity markets became more interconnected as countries opened to international trade and capital flows and that there was an increasing impact of Spain on Latin American equity markets. Stronger economic linkages (more trade and foreign direct investment) between Spain and these countries, especially in Brazil, seem to explain increased equity market interconnectedness. Research limitations/implications: The study limitations are, in general, the same that apply to the VAR methodology, and in particular, to missing control variables or to possible bias in the selection of the subsample periods used as historical benchmarks. Originality/value: To our knowledge, no other work showed that there was an increasing impact of Spain on Latin American equity markets during the neoliberal reform period by using IRFs and VAR models.
Keywords Emerging markets, VAR modeling, Stock markets interdependence, Spain, Latin America
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Abstract Two recent contributions have found conditions for large dimensional networks or systems to generate long memory in their individual components. We build on these and provide a multivariate methodology for modeling and forecasting series displaying long range dependence. We model long memory properties within a vector autoregressive system of order 1 and consider Bayesian estimation or ridge regression. For these, we derive a theory-driven parametric setting that informs a prior distribution or a shrinkage target. Our proposal significantly outperforms univariate time series long-memory models when forecasting a daily volatility measure for 250 U.S. company stocks over twelve years. This provides an empirical validation of the theoretical results showing long memory can be sourced to marginalization within a large dimensional system.
Keywords Model Forecasting, Vector autoregressive, Ridge regression, Bayesian estimation
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