Publications

Most of the information presented on this page have been retrieved from RePEc with the kind authorization of Christian Zimmermann
Impact of COVID-19 Activity Restrictions on Air Pollution: Methodological Considerations in the Economic Valuation of the Long-Term Effects on MortalityJournal articleOlivier Chanel, Economie et Statistique / Economics and Statistics, Issue 534-35, pp. 103-118, 2022

Cet article propose une approche intégrant le temps de latence dans le processus d’évaluation de la mortalité de long terme et dans sa valorisation économique, suite à un choc transitoire. Il l’applique aux conséquences des restrictions d’activité en lien avec la Covid‑19 au printemps 2020 sur la pollution de l’air ambiant en France. Ces conséquences sont évaluées en termes d’années de vie gagnées (AVG) ainsi qu’en termes monétaires pour deux indicateurs de pollution de l’air. Cette approche est comparée à une estimation standard par différence. Elle conduit à des résultats inférieurs d’un facteur 3.7 à 5.5 pour les AVG et, du fait de l’influence additionnelle de l’actualisation, à une valorisation économique inférieure d’un facteur 4.7 à 6.9. Ces résultats indiquent qu’une évaluation adaptée des bénéfices sanitaires de long terme, puis leur traduction en termes monétaires, est essentielle pour comparer les conséquences à long terme de politiques ou de chocs exogènes transitoires.

The size effect and default risk: Evidence from the Vietnamese stock marketJournal articleLe Quy Duong and Philippe Bertrand, Review of Financial Economics, Volume 40, Issue 4, pp. 377-388, 2022

The literature is inconclusive on the source of the size effect. Our paper contributes to extant studies by investigating the relationship between the size premium and default risk in Vietnam, an important frontier emerging market. The debt-to-equity ratio and distance-to-default of Merton (1974, The Journal of Finance, 29, 449) are used as distress-risk proxies. Based on more than 300 listed stocks over 2009–2019, we discover that the small portfolio delivers the highest average return. The excess return on the small portfolio is concentrated in firms with high distress risk. Furthermore, neutral size factors are built to dissect returns on the Fama-French size factor from the default-risk premium. Empirical results prove that the explanatory power of the size factor is negatively affected when the default-risk neutrality is applied. Given this backdrop, the size premium in Vietnam is likely to be compensation for distress risk, consistent with a risk-based point of view.

Environmental costs of the global job market for economistsJournal articleAlberto Prati, Olivier Chanel and Morgan Raux, CentrePiece LSE-UKRI, Volume 27, Issue 3, pp. 9-11, 2022
Quelles leçons de l’histoire ? ou comment faire face aux fortes augmentations de dette publique ?Journal articleVincent Bignon and Pierre Sicsic, Revue d'économie financière, Volume 146, Issue 2, pp. 41-66, 2022

De nouvelles interventions publiques sont en débat pour lutter contre le dérèglement climatique, gérer la crise énergétique et les difficultés sanitaires, entre autres. Ces débats ont lieu dans un environnement singulier pour les finances publiques des pays développés. En effet, le niveau de dettes publiques a augmenté depuis 2017 pour atteindre des niveaux inédits en temps de paix. La gestion de ces dettes publiques conditionne les évolutions budgétaires à venir et le financement des futurs investissements publics, par l’impôt, de nouvelles dettes ou par des baisses d’autres dépenses publiques.Les niveaux actuels des dettes publiques sont parfois jugés inquiétants, sans que la question de leur soutenabilité ou désirabilité soit clairement explicitée. Par ailleurs, les différentes politiques de réduction de dettes publiques à des niveaux souhaitables doivent être comparées quant à leur effet de court terme et long terme. Quel est l’horizon raisonnable de réduction de dettes publiques, 5 ans ou 20 ans ? Quel est ce niveau de dettes publiques à la fois souhaitables et soutenables ? Ces questions difficiles doivent éclairer le débat de politique économique et de manière concrète le cadre européen de coordination budgétaire.Ce numéro aborde ce débat en revenant sur l’histoire des dettes publiques du XVIIIe au XXIe siècle, qui est riche d’enseignements. Il présente le débat économique sur le niveau souhaitable et soutenable des dettes publiques, en discutant à la fois sa dimension économique et politique. Enfin, des propositions de gestion des dettes publiques sont exposées, comme leurs implications pour le débat européen.

E-procurement and firm corruption to secure public contracts: The moderating role of governance institutions and supranational supportJournal articleAlfredo Jiménez, Julien Hanoteau and Ralf Barkemeyer, Journal of Business Research, Volume 149, pp. 640-650, 2022

This paper investigates the effects of e-procurement on firm corruption to secure public contracts, highlighting the moderating roles of the quality of governance institutions and supranational support in that relationship. Taking transaction cost economics as our theoretical lens, and building on a sample of 8,373 firms in 72 countries from 2008 to 2019, we find that the adoption of an e-procurement system in fact reduces firm corruption. However, this effect is only unveiled once one accounts in the analysis for the quality of country-level governance institutions, which also makes the relationship stronger. We also find an e-procurement system only to effectively address firm corruption when it benefits from supranational support. The study contributes to the ongoing academic debate on the impact of digitalization on corruption.

General Versions of the Ekeland Variational Principle: Ekeland Points and Stop and Go DynamicsJournal articleLe Phuoc Hai, Phan Quoc Khanh and Antoine Soubeyran, Journal of Optimization Theory and Applications, Volume 195, Issue 1, pp. 347-373, 2022

We establish general versions of the Ekeland variational principle (EVP), where we include two perturbation bifunctions to discuss and obtain better perturbations for obtaining three improved versions of the principle. Here, unlike the usual studies and applications of the EVP, which aim at exact minimizers via a limiting process, our versions provide good-enough approximate minimizers aiming at applications in particular situations. For the presentation of applications chosen in this paper, the underlying space is a partial quasi-metric one. To prove the aforementioned versions, we need a new proof technique. The novelties of the results are in both theoretical and application aspects. In particular, for applications, using our versions of the EVP together with new concepts of Ekeland points and stop and go dynamics, we study in detail human dynamics in terms of a psychological traveler problem, a typical model in behavioral sciences.

Winners and losers of the COVID-19 pandemic: An excess profits tax proposalJournal articleCéline Azémar, Rodolphe Desbordes, Paolo Melindi-Ghidi and Jean-Philippe Nicolaï, Journal of Public Economic Theory, Volume 24, Issue 5, pp. 1016-1038, 2022

In this paper, we study the gains and losses incurred during the COVID-19 pandemic. We distinguish between the effects of the pandemic and those of the health measures implemented to reduce the death toll, notably “the lockdown.” Our theoretical model is focused on within-sector firm heterogeneity and involves imperfect competition in a partial equilibrium setting. A comparison between the gains and losses triggered by both the pandemic and the lockdown indicates that an excess profits tax imposed on the “winners” could partly compensate the “losers” of the same sector.

Optimal lockdowns for COVID-19 pandemics: Analyzing the efficiency of sanitary policies in EuropeJournal articleEwen Gallic, Michel Lubrano and Pierre Michel, Journal of Public Economic Theory, Volume 24, Issue 5, pp. 944-967, 2022

Two main nonpharmaceutical policy strategies have been used in Europe in response to the COVID-19 epidemic: one aimed at natural herd immunity and the other at avoiding saturation of hospital capacity by crushing the curve. The two strategies lead to different results in terms of the number of lives saved on the one hand and production loss on the other hand. Using a susceptible–infected–recovered–dead model, we investigate and compare these two strategies. As the results are sensitive to the initial reproduction number, we estimate the latter for 10 European countries for each wave from January 2020 till March 2021 using a double sigmoid statistical model and the Oxford COVID-19 Government Response Tracker data set. Our results show that Denmark, which opted for crushing the curve, managed to minimize both economic and human losses. Natural herd immunity, sought by Sweden and the Netherlands does not appear to have been a particularly effective strategy, especially for Sweden, both in economic terms and in terms of lives saved. The results are more mixed for other countries, but with no evident trade-off between deaths and production losses.

Limited‐tenure concessions for collective goodsJournal articleNicolas Quérou, Agnès Tomini and Christopher Costello, Journal of Economic Dynamics and Control, Volume 143, pp. 104484, 2022

We analyze theoretically an institution called a “limited-tenure concession” for its ability to induce efficient public goods contribution and common-pool resource extraction. The basic idea is that by limiting the tenure over which an agent can enjoy the public good, but offering the possibility of renewal contingent on ample private provision of that good, efficient provision may be induced. We first show in a simple repeated game setting that limited-tenure concessions can incentivize socially-efficient provision of public goods. We then analyze the ability of this instrument to incentivize the first best provision for common-pool natural resources such as fish and water, thus accounting for spatial connectivity and growth dynamics of the resource. The duration of tenure and the dispersal of the resource play pivotal roles in whether this limited-tenure concession induces the socially optimal private provision. Finally, in a setting with costly monitoring, we discuss the features of a concession contract that ensure first-best behavior, but at least cost to the implementing agency.

Abstract regularized equilibria: application to Becker’s household behavior theoryJournal articleJoao Xavier Cru Neto, J. O. Lopes, Antoine Soubeyran and João Carlos O. Souza, Annals of Operations Research, Volume 316, Issue 2, pp. 1279-1300, 2022

In this paper, we consider an abstract regularized method with a skew-symmetric mapping as regularization for solving equilibrium problems. The regularized equilibrium problem can be viewed as a generalized mixed equilibrium problem and some existence and uniqueness results are analyzed in order to study the convergence properties of the algorithm. The proposed method retrieves some existing one in the literature on equilibrium problems. We provide some numerical tests to illustrate the performance of the method. We also propose an original application to Becker’s household behavior theory using the variational rationality approach of human dynamics.