Publications

Most of the information presented on this page have been retrieved from RePEc with the kind authorization of Christian Zimmermann
Spatial PolarizationJournal articleFabio Cerina, Elisa Dienesch, Alessio Moro and Michelle Rendall, The Economic Journal, Forthcoming

We document the emergence of spatial polarization in the U.S. during the 1980- 2008 period. This phenomenon is characterized by stronger employment polarization in larger cities, both at the occupational and the worker level. We quantitatively evaluate the role of technology in generating these patterns by constructing and calibrating a spatial equilibrium model. We find that faster skill- biased technological change in larger cities can account for a substantial fraction of spatial polarization in the U.S. Counterfactual exercises suggest that the differential increase in the share of low-skilled workers across city size is due mainly to the large demand by high-skilled workers for low-skilled services and to a smaller extent to the higher complementarity between low- and high-skilled workers in production relative to middle-skilled workers.

Estimating willingness to pay for public health insurance while accounting for protest responses: A further step towards universal health coverage in Tunisia?Journal articleMohammad Abu-Zaineh, Olivier Chanel and Khaled Makhloufi, The International Journal of Health Planning and Management, Volume n/a, Issue n/a, Forthcoming

Introduction:
Developing countries face major challenges in implementing universal health coverage (UHC): a widespread informal sector, general discontent with rising economic insecurity and inequality and the rollback of state and public welfare. Under such conditions, estimating the demand for a health insurance scheme (HIS) on voluntary basis can be of interest to accelerate the progress of UHC-oriented reforms. However, a major challenge that needs to be addressed in such context is related to protest attitudes that may reflect, inter alia, a null valuation of the expected utility or unexpressed demand.
Methods:
We propose to tackle this by applying a contingent valuation survey to a non-healthcare-covered Tunisian sample vis-à-vis joining and paying for a formal HIS. Our design pays particular attention to identifying the nature of the willingness-to-pay (WTP) values obtained, distinguishing genuine null values from protest values. To correct for potential selection issues arising from protest answers, we estimate an ordered-Probit-selection model and compare it with the standard Tobit and Heckman sample selection models.
Results:
Our results support the presence of self-selection and, by predicting protesters' WTP, allow the “true” sample mean WTP to be computed. This appears to be about 14% higher than the elicited mean WTP.
Conclusion:
The WTP of the poorest non-covered respondents represents about one and a half times the current contributions of the poorest formal sector enrolees, suggesting that voluntary participation in the formal HIS is feasible.

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 n/a, Issue n/a, Forthcoming

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.

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 n/a, Issue n/a, Forthcoming

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.

Pareto solutions as limits of collective traps: an inexact multiobjective proximal point algorithmJournal articleG. C. Bento, J. X. Cruz Neto, L. V. Meireles and Antoine Soubeyran, Annals of Operations Research, Forthcoming

In this paper we introduce a definition of approximate Pareto efficient solution as well as a necessary condition for such solutions in the multiobjective setting on Riemannian manifolds. We also propose an inexact proximal point method for nonsmooth multiobjective optimization in the Riemannian context by using the notion of approximate solution. The main convergence result ensures that each cluster point (if any) of any sequence generated by the method is a Pareto critical point. Furthermore, when the problem is convex on a Hadamard manifold, full convergence of the method for a weak Pareto efficient solution is obtained. As an application, we show how a Pareto critical point can be reached as a limit of traps in the context of the variational rationality approach of stay and change human dynamics.

Dynamic monopoly and consumers profiling accuracyJournal articleDidier Laussel, Ngo Van Long and Joana Resende, Journal of Economics & Management Strategy, Volume n/a, Issue n/a, Forthcoming

Using a Markov-perfect equilibrium model, we show that the use of customer data to practice intertemporal price discrimination will improve monopoly profit if and only if information precision is higher than a certain threshold level. This U-shaped relationship lends support to a popular view that knowledge is good only if it is sufficiently refined. When information accuracy can only be achieved through costly investment, we find that investing in profiling is profitable only if this allows to reach a high enough level of information precision. Consumers expected surplus being a hump-shaped function of information accuracy, we show that consumers have an incentive to lobby for privacy protection legislation which raises the cost of monopoly's investment in information accuracy. However, this cost should not dissuade firms to collect some information on customers' tastes, as the absence of consumers' profiling is actually detrimental to consumers.

Coercivity and generalized proximal algorithms: application—traveling around the worldJournal articleErik A. Papa Quiroz, Antoine Soubeyran and Paulo R. Oliveira, Annals of Operations Research, Forthcoming

We present an inexact proximal point algorithm using quasi distances to solve a minimization problem in the Euclidean space. This algorithm is motivated by the proximal methods introduced by Attouch et al., section 4, (Math Program Ser A, 137: 91–129, 2013) and Solodov and Svaiter (Set Valued Anal 7:323–345, 1999). In contrast, in this paper we consider quasi distances, arbitrary (non necessary smooth) objective functions, scalar errors in each objective regularized approximation and vectorial errors on the residual of the regularized critical point, that is, we have an error on the optimality condition of the proximal subproblem at the new point. We obtain, under a coercivity assumption of the objective function, that all accumulation points of the sequence generated by the algorithm are critical points (minimizer points in the convex case) of the minimization problem. As an application we consider a human location problem: How to travel around the world and prepare the trip of a lifetime.

The Macroeconomic Impact of the 1918–19 Influenza Pandemic in SwedenJournal articleMartin Karlsson, Mykhailo Matvieiev and Maksym Obrizan, The B.E. Journal of Macroeconomics, Forthcoming

In this paper, we develop an overlapping generations model with endogenous fertility and calibrate it to the Swedish historical data in order to estimate the economic cost of the 1918–19 influenza pandemic. The model identifies survivors from younger cohorts as main benefactors of the windfall bequests following the influenza mortality shock. We also show that the general equilibrium effects of the pandemic reveal themselves over the wage channel rather than the interest rate, fertility or labor supply channels. Finally, we demonstrate that the influenza mortality shock becomes persistent, driving the aggregate variables to lower steady states which costs the economy 1.819% of the output loss over the next century.

Other-regarding preferences and giving decision in a risky environment: experimental evidenceJournal articleMickael Beaud, Mathieu Lefebvre and Julie Rosaz, Review of Economic Design, Forthcoming

We investigate whether and how an individual giving decision is affected in risky environments in which the recipient’s wealth is random. We demonstrate that, under risk neutrality, the donation of dictators with a purely ex post view of fairness should, in general, be affected by the riskiness of the recipient’s payoff, while dictators with a purely ex ante view should not be. Furthermore, we observe that some influential inequality aversion preferences functions yield opposite predictions when we consider ex post view of fairness. Hence, we report on dictator games laboratory experiments in which the recipient’s wealth is exposed to an actuarially neutral and additive background risk. Our experimental data show no statistically significant impact of the recipient’s risk exposure on dictators’ giving decisions. This result appears robust to both the experimental design (within subjects or between subjects) and the origin of the recipient’s risk exposure (chosen by the recipient or imposed on the recipient). Although we cannot sharply validate or invalidate alternative fairness theories, the whole pattern of our experimental data can be simply explained by assuming ex ante view of fairness and risk neutrality.

Pareto models for top incomes and wealthJournal articleArthur Charpentier and Emmanuel Flachaire, The Journal of Economic Inequality, Forthcoming

Top incomes are often related to Pareto distribution. To date, economists have mostly used Pareto Type I distribution to model the upper tail of income and wealth distribution. It is a parametric distribution, with interesting properties, that can be easily linked to economic theory. In this paper, we first show that modeling top incomes with Pareto Type I distribution can lead to biased estimation of inequality, even with millions of observations. Then, we show that the Generalized Pareto distribution and, even more, the Extended Pareto distribution, are much less sensitive to the choice of the threshold. Thus, they can provide more reliable results. We discuss different types of bias that could be encountered in empirical studies and, we provide some guidance for practice. To illustrate, two applications are investigated, on the distribution of income in South Africa in 2012 and on the distribution of wealth in the United States in 2013.