Publications

La plupart des informations présentées ci-dessous ont été récupérées via RePEc avec l'aimable autorisation de Christian Zimmermann
I want to tell you? Maximizing revenue in first-price two-stage auctionsJournal articleGalit Ashkenazi-Golan, Yevgeny Tsodikovich et Yannick Viossat, Economic Theory, Volume 76, pp. 1329–1362, 2023

A common practice in many auctions is to offer bidders an opportunity to improve their bids, known as a best and final offer stage. This improved bid can depend on new information either about the asset or about the competitors. This paper examines the effects of new information regarding competitors, seeking to determine what information the auctioneer should provide assuming the set of allowable bids is discrete. The rational strategy profile that maximizes the revenue of the auctioneer is the one where each bidder makes the highest possible bid that is lower than his valuation of the item. This strategy profile is an equilibrium for a large enough number of bidders, regardless of the information released. We compare the number of bidders needed for this profile to be an equilibrium under different information structures. We find that it becomes an equilibrium with fewer bidders when less additional information is made available to the bidders regarding the competition. It follows that when the number of bidders is a priori unknown, there are some advantages to the auctioneer not revealing information and conducting a one-stage auction instead.

Can workers still climb the social ladder as middling jobs become scarce? Evidence from two British cohortsJournal articleCecilia Garcia-Peñalosa, Fabien Petit et Tanguy van Ypersele, Labour Economics, Volume 84, pp. 102390, 2023

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 shift-share 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.

Gender differences in re-contesting decisions: New evidence from French municipal electionsJournal articleJulieta Peveri et Marc Sangnier, Journal of Economic Behavior & Organization, Volume 214, pp. 574-594, 2023

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.

Does age affect the relation between risk and time preferences? Evidence from a representative sampleJournal articleZexuan Wang, Ismael Rafai et Marc Willinger, Southern Economic Journal, Volume 90, Issue 2, pp. 341-368, 2023

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.

Can you spot a scam? Measuring and improving scam identification abilityJournal articleElif Kubilay, Eva Raiber, Lisa Spantig, Jana Cahlíková et Lucy Kaaria, Journal of Development Economics, Volume 165, pp. 103147, 2023

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.

The discounting premium puzzle: Survey evidence from professional economistsJournal articleChristian Gollier, Frederick van der Ploeg et Jiakun Zheng, Journal of Environmental Economics and Management, Volume 122, pp. 102882, 2023

We surveyed economists’ attitudes toward adjusting discount rates to the risk profile of public programs. Three-quarters of respondents recommend to use project-specific discount rates. For example, on average, respondents discount railway infrastructures more than hospitals and climate mitigation. But the degree of discount discrimination between distinct risk profiles of different projects is fairly limited in our sample given the differences in risk profiles for these projects. Economic experts thus penalize risky public projects far less than financial markets penalize private investments. We call this the ”discount premium puzzle”. Finally, among experts in favor of a single discount rate, there is no consensus on whether it should be based on the average cost of capital in the economy, the sovereign borrowing cost, or the Ramsey rule, which gives rise to disagreement over the level of the recommended discount rate.

Colonial origins and quality of education evidence from cameroonJournal articleYasmine Bekkouche et Yannick Dupraz, World Development, Volume 170, pp. 106245, 2023

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.

Are the Liquidity and Collateral Roles of Asset Bubbles Different?Journal articleLise Clain-Chamosset-Yvrard, Xavier Raurich et Thomas Seegmuller, Journal of Money, Credit and Banking, Volume 55, Issue 6, pp. 1443-1473, 2023

Several papers explain why asset bubbles are observed when growth is large. These papers differ in the role of the bubble, used to provide liquidities or as collateral in a borrowing constraint. We compare the liquidity and collateral roles of bubbles in an overlapping generations model. When the bubble is deterministic, the equilibrium is identical under these two roles, implying that the same mechanism explains the crowding-in effect of the bubble on growth. With stochastic bubbles, growth is larger when bubbles play the liquidity role, because the burst of a bubble used for liquidity is less damaging to capital investors.

Mandatory membership of community-based mutual health insurance in Senegal: A national surveyJournal articleValéry Ridde, Ibrahima Gaye, Bruno Ventelou, Elisabeth Paul et Adama Faye, PLOS Global Public Health, Volume 3, Issue 9, pp. e0001859, 2023

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.

We modeled long memory with just one lag!Journal articleLuc Bauwens, Guillaume Chevillon et Sébastien Laurent, Journal of Econometrics, Volume 236, Issue 1, pp. 105467, 2023

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.