Publications

La plupart des informations présentées ci-dessous ont été récupérées via RePEc avec l'aimable autorisation de Christian Zimmermann
US churches' response to Covid-19: Results from FacebookJournal articleEva Raiber et Paul Seabright, Covid Economics, Volume 61, pp. 121-171, 2020

This study investigates U.S. churches' response to the SARS-CoV-2 pandemic by looking at their public Facebook posts. For religious organizations, in-person gatherings are at the heart of their activities. Yet religious in-person gatherings have been identified as some of the early hot spots of the pandemic, but there has also been controversy over the legitimacy of public restrictions on such gatherings. Our sample contains information on church characteristics and Facebook posts for nearly 4000 churches that posted at least once in 2020. The share of churches that offer an online church activity on a given Sunday more than doubled within two weeks at the beginning of the pandemic (the first half of March 2020) and stayed well above baseline levels. Online church activities are positively correlated with the local pandemic situation at the beginning, but uncorrelated with most state interventions. After the peak of the first wave (mid April), we observe a slight decrease in online activities. We investigate heterogeneity in the church responses and find that church size and worship style explain differences consistent with churches facing different demand and cost structures. Local political voting behavior, on the other hand, explains little of the variation. Descriptive analysis suggests that overall online activities, and the patterns of heterogeneity, remain unchanged through end-November 2020

How French general practitioners respond to declining medical density: a study on prescription practices, with an insight into opioids useJournal articleJulien Silhol, Bruno Ventelou et Anna Zaytseva, The European Journal of Health Economics, Volume 21, Issue 9, pp. 1391-1398, 2020

Disparities in physicians' geographical distribution lead to highly unequal access to healthcare, which may impact quality of care in both high and low-income countries. This paper uses a 2013–2014 nationally representative survey of French general practitioners (GPs) matched with corresponding administrative data to analyze the effects of practicing in an area with weaker medical density. To avoid the endogeneity issue on physicians' choice of the location, we enriched our variable of interest, practicing in a relatively underserved area, with considering changes in medical density between 2007 and 2013, thus isolating GPs who only recently experienced a density decline (identifying assumption). We find that GPs practicing in underserved areas do shorter consultations and tend to substitute time-consuming procedures with alternatives requiring fewer human resources, especially for pain management. Results are robust to considering only GPs newly exposed to low medical density. Findings suggest a significant impact of supply-side shortages on the mix of healthcare services used to treat patients, and point to a plausible increased use of painkillers, opioids in particular.

Equilibrium versions of set-valued variational principles and their applications to organizational behaviorJournal articleJing-Hui Qiu, Antoine Soubeyran et Fei He, Optimization, Volume 69, Issue 12, pp. 2657-2693, 2020

By using a pre-order principle in [Qiu JH. A pre-order principle and set-valued Ekeland variational principle. J Math Anal Appl. 2014;419:904–937], we establish a general equilibrium version of set-valued Ekeland variational principle (denoted by EVP), where the objective function is a set-valued bimap defined on the product of left-complete quasi-metric spaces and taking values in a quasi-ordered linear space, and the perturbation consists of a cone-convex subset of the ordering cone multiplied by the quasi-metric. Moreover, we obtain an equilibrium EVP, where the perturbation contains a σ-convex subset and the quasi-metric. From the above two general EVPs, we deduce several interesting corollaries, which extend and improve the related known results. Several examples show that the obtained set-valued EVPs are new. Finally, applying the above EVPs to organizational behavior sciences, we obtain some interesting results on organizational change and development with leadership. In particular, we show that the existence of robust organizational traps.

Threshold regressions for the resource curseJournal articleNicolas Clootens et Djamel Kirat, Environment and Development Economics, Volume 25, Issue 6, pp. 583-610, 2020

This paper analyzes the behavior of cross-country growth rates with respect to resource abundance and dependence. We reject the linear model that is commonly used in growth regressions in favor of a multiple-regime alternative. Using a formal sample-splitting method, we find that countries exhibit different behaviors with respect to natural resources depending on their initial level of development. In high-income countries, natural resources play only a minor role in explaining the differences in national growth rates. On the contrary, in low-income countries, abundance seems to be a blessing but dependence restricts growth.

Unconventional monetary policy reaction functions: evidence from the USJournal articleLuca Agnello, Vitor Castro, Gilles Dufrénot, Fredj Jawadi et Ricardo M. Sousa, Studies in Nonlinear Dynamics & Econometrics, Volume 24, Issue 4, pp. pp18, 2020

We specify unconventional monetary policy reaction functions for the Fed using linear and nonlinear econometric frameworks. We find that nonstandard policy measures are largely driven by the dynamics of inflation and the output gap, with the effect being particularly strong during QE rounds. Moreover, we uncover the presence of asymmetry and regime dependence in central bank’s actions since the global financial crisis, especially concerning the response of the term spread and the shadow short rate to the growth rate of central bank reserves. From a policy perspective and given the lack of a systematic response of monetary policy to asset price growth in nonstandard times, our findings seem to corroborate the view that concerns about asset price bubbles, financial sector pro-cyclicality and systemic risk should be part of the macro-prudential policy toolkit.

Évaluation économique de la mortalité liée à la pollution atmosphérique en FranceJournal articleOlivier Chanel, Sylvia Medina et Mathilde Pascal, Journal de gestion et d'Economie de la santé, Volume 38, Issue 2, pp. 77-92, 2020

Cet article propose une discussion méthodologique à partir d’une évaluation économique des impacts sur la mortalité de l’exposition chronique aux particules fines en France continentale. Il prend comme point de départ l’évaluation quantitative d’impact sanitaire (EQIS), réalisée par Santé publique France en 2016, de 5 scénarios de réduction des concentrations par deux méthodes de mesure de la mortalité (nombre de décès prématurés évités et nombre total d’années de vie gagnées). Après une justification des valeurs monétaires utilisées – 3 millions € pour la valeur d’évitement d’un décès et 80 000 € pour celle d’une année de vie gagnée – nous les appliquons aux données sanitaires, et obtenons des résultats comparables aux études contemporaines. En particulier, dans un scénario sans pollution anthropique, l’EQIS de 2016 estime à 48 283 les décès prématurés évités, que nous évaluons à 144,85 milliards €2008. Nous questionnons ensuite les méthodes et pratiques, en commençant par identifier les sources de divergence avec la précédente étude française menée en 1998-99, dont l’évaluation était 5 fois moindre en dépit d’émissions particulaires plus élevées. Puis, nous discutons le choix des valeurs monétaires et les conditions d’utilisation de ces résultats dans la décision publique. Au final, nous apportons un argument supplémentaire sur la nécessité de réduire l’exposition des populations à la pollution de l’air ambiant en France.

Complementary Monopolies with asymmetric informationJournal articleDidier Laussel et Joana Resende, Economic Theory, Volume 70, Issue 4, pp. 943-981, 2020

We investigate how asymmetric information on final demand affects strategic interaction between a downstream monopolist and a set of upstream monopolists, who independently produce complementary inputs. We study an intrinsic private common agency game in which each supplieriindependently proposes a pricing schedule contract to the assembler, specifying the supplier's payment as a function of the assembler's purchase of inputi. We provide a necessary and sufficient equilibrium condition. A lot of equilibria satisfy this condition but there is a unique Pareto-undominated Nash equilibrium from the suppliers' point of view. In this equilibrium, there are unavoidable efficiency losses due to excessively low sales of the good. However, suppliers may be able to limit these distortions by implicitly coordinating on an equilibrium with a rigid (positive) output in bad demand circumstances.

Special Issue: Supermodularity and Monotonicity in EconomicsJournal articleRabah Amir, Economic Theory, Volume 70, Issue 4, pp. 907-911, 2020

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God insures those who pay? Formal insurance and religious offerings in Ghana.Journal articleEmmanuelle Auriol, Julie Lassébie, Amma Panin, Eva Raiber et Paul Seabright, The Quarterly Journal of Economics, Volume 135, Issue 4, pp. 1799-1848, 2020

This paper provides experimental support for the hypothesis that insurance can be a motive for religious donations. We randomize enrollment of members of a Pentecostal church in Ghana into a commercial funeral insurance policy. Then church members allocate money between themselves and a set of religious goods in a series of dictator games with significant stakes. Members enrolled in insurance give significantly less money to their own church compared to members that only receive information about the insurance. Enrollment also reduces giving towards other spiritual goods. We set up a model exploring different channels of religiously based insurance.
The implications of the model and the results from the dictator games suggest that adherents perceive the church as a source of insurance and that this insurance is derived from beliefs in an interventionist God. Survey results suggest that material insurance from the church community is also important and we hypothesize that these two insurance channels exist in parallel.

Convergence of GDP per capita in advanced countries over the twentieth centuryJournal articleAntonin Bergeaud, Gilbert Cette et Rémy Lecat, Empirical Economics, Volume 59, Issue 5, pp. 2509-2526, 2020

This study compares GDP per capita levels and growth rates across 17 advanced economies over the period 1890–2013 using an accounting breakdown and runs Phillips and Sul (Econometrica 75(6):1771–1855, 2007) convergence tests. An overall convergence process has been at work among advanced economies, mainly after WWII, driven mostly by capital intensity and then TFP, while trends in hours worked and employment rates are disparate. However, this convergence process came to a halt during technology shocks, during the two world wars and since the 1990s, with the convergence of advanced economies stopping far from the level of US GDP per capita.