Publications

Abstract We study price personalization in a two period duopoly with vertically differentiated products. In the second period, a firm not only knows the purchase history of all customers, as in standard Behavior Based Price Discrimination models, but it also collects detailed information on its old customers, using it to engage in price personalization. The analysis reveals that there exists a natural market for each firm, defined as the set of customers that cannot be poached by the rival in the second period. The equilibrium is unique, except when firms are ex-ante almost identical. In equilibrium, only the firm with the largest natural market poaches customers from the rival. This firm has highest profits but not necessarily the largest market share. Aggregate profits are lower than under uniform pricing. All consumers gain, total welfare is higher herein than under uniform pricing if firms’ natural markets are sufficiently asymmetric. The low quality firm chooses the minimal quality level and a quality differential arises, though the exact choice for the high quality depends upon the cost specification.
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Abstract Gilles Campagnolo a traduit et édité une œuvre majeure de la science économique, les Principes de Carl Menger, le prédécesseur et le maître, en Autriche, de Böhm-Bawerk, Mises, Hayek, Schumpeter, et de bien d’autres. En France son œuvre était connue de Rist, Colson, Perroux, Bousquet, mais depuis que les économistes français ne savent plus l’allemand elle est ignorée. En revanche, elle a bénéficié aux États-Unis d’une traduction et de l’émigration, dans les années trente, des grands économistes autrichiens vers les universités américaines. Gilles Compagnolo a bien voulu présenter à nos lecteurs cette savante et importante édition.
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Abstract Background Asthma affects over 330 million people worldwide. Timing of an asthma event is extremely important and lack of identification of asthma increases the risk of death. A major challenge for health systems is the length of time between symptom onset and care seeking, which could result in delayed treatment initiation and worsening of symptoms. Objective This study evaluates the utility of the internet search query data for the identification of the onset of asthma symptoms. Methods Pearson correlation coefficients between the time series of hospital admissions and Google searches were computed at lag times from 4 weeks before hospital admission to 4 weeks after hospital admission. An autoregressive integrated moving average (ARIMAX) model with an autoregressive process at lags of 1 and 2 and Google searches at weeks –1 and –2 as exogenous variables were conducted to validate our correlation results. Results Google search volume for asthma had the highest correlation at 2 weeks before hospital admission. The ARIMAX model using an autoregressive process showed that the relative searches from Google about asthma were significant at lags 1 (P
Keywords Health information seeking, Symptoms, Asthma, Google queries, Digital epidemiology
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Abstract Detailed knowledge about hepatitis B virus (HBV) vaccination coverage and timeliness for sub-Saharan Africa is scarce. We used data from a community-based cross-sectional survey conducted in 2018–2019 in the area of Niakhar, Senegal, to estimate coverage, timeliness, and factors associated with non-adherence to the World Health Organisation-recommended vaccination schedules in children born in 2016 (year of the birth dose (BD) introduction in Senegal) and 2017–2018. Vaccination status was assessed from vaccination cards, surveillance data, and healthcare post vaccination records. Among 241 children with available data, for 2016 and 2017–2018, respectively, 31.0% and 66.8% received the BD within 24 h of birth (BD schedule), and 24.3% and 53.7% received the BD plus at least two pentavalent vaccine doses within the recommended timeframes (three-dose schedule). In logistic regression models, home birth, dry season birth, and birth in 2016 were all associated with non-adherence to the recommended BD and three-dose schedules. Living over three kilometres from the nearest healthcare post, being the firstborn, and living in an agriculturally poorer household were only associated with non-adherence to the three-dose schedule. The substantial proportion of children not vaccinated according to recommended schedules highlights the importance of considering vaccination timeliness when evaluating vaccination programme effectiveness. Outreach vaccination activities and incentives to bring children born at home to healthcare facilities within 24 h of birth, must be strengthened to improve timely HBV vaccination.
Keywords Vaccination coverage, Vaccination timeliness, Senegal, Pentavalent vaccination, Hepatitis B vaccine, Birth dose vaccination
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Abstract Land is back. The increase in wealth in the second half of 20th century arose from housing and land. It should be taxed. We introduce land and housing structures in Judd’s standard setup: first best optimal taxation is achieved with a property tax on land and requires no tax on capital. With positive taxes on housing rents, a first best is still possible but with subsidies to rental housing investments, and either with differential land tax rates or with a tax on imputed rents. It can be taxed. Even absent land taxes, one can tax it indirectly and reach a Ramsey-second best still with no tax on capital and positive housing rent taxes in the steady-state. This result extends to the dynamics under restrictions on parameters.
Keywords Capital, Wealth, Housing, Land, Optimal tax, First best, Second best
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Abstract Une stratégie financière doit aboutir à la rencontre d’une offre avec une demande de fonds en spécifiant les conditions spécifiques de cet échange et on doit naturellement s’attendre à ce que les temps de crise voient émerger des stratégies spécifiques. Pour apprécier la pertinence de ces stratégies nous rappelons les principes du financement des activités économiques en soulignant l’importance de la qualité de l’information des décideurs. Dans un deuxième temps nous nous penchons sur le rôle que l’État peut jouer en matière de financement (sections 2 et 3). Afin de correctement comparer les différentes stratégies de financement il est essentiel de prendre en compte les bénéfices mais aussi les coûts – directs mais, plus important encore, indirects – de ces stratégies (section 4). La prise en compte de tous ces paramètres conduit au plus grand scepticisme à l’égard des stratégies qui ont eu les préférences de nombreux États depuis le début de la crise de 2020.
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Abstract Austrian Economics and Public Choice are used to analyze the erratic administrative decision-making process during the Covid-19 crisis. Lockdowns policies had added a new page to the economic planning debate. The paper focus on the centralization/decentralization level of the decision and on the actors’ incentives. We use an Hayekian perspective on knowledge spreading in order to explain the crucial needs of human interactions. Lockdowns had pushed social organization toward more autarkist schemes. These measures confront heavily with the core organization of open societies, creating worry economic consequences without any proved positive effect on public healthcare.
Keywords Knowledge, Austrian school, Public choice, Connaissance, École autrichienne, Choix public
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Abstract Preferences elicitation can be a challenging exercise for citizens participating in assessment surveys. It is even more challenging when it comes to complex and unfamiliar ecosystems and the threatened ecosystem services they provide. Making people aware of the characteristics of the ecosystem services being valued is determinant for the assessment process. We investigated the impact of familiarity and academic information supply on people's preferences for twenty selected ecosystem services of French Mediterranean coastal lagoons. The results show that regardless of familiarity and information supply, there is a strong consensus about the highest importance of regulation and maintenance ecosystem services as well as environmental education and research opportunity ecosystem services. By contrast, nine of the cultural ecosystem services, together with two provisioning ecosystem services showed heterogeneous preferences among the different citizen groups. Using a combination of descriptive and inferential statistics these eleven ecosystem services split up into three clusters characterized as (i) contemplative leisure, (ii) heritage, and (iii) consumptive activities. Familiarity and academic information supply had a strong impact on the preferences for these three clusters of ecosystem services.
Keywords Cultural ecosystem services CES, Veil of ignorance, Paternalism, Citizens&#039, workshop, Coastal lagoons, Preference elicitation
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Abstract This chapter discusses whether the Middle East and North African (MENA) countries are prone to be cursed or blessed by their natural resources endowments. It thus reviews the literature on the resource curse theory. The existence of a resource curse is discussed and arguments against advocates of the resource curse are presented. Then, the resource curse transmission channels are presented. Finally, we present to what extent MENA countries are affected by the curse, drawing on existing literature as well as empirical data. The (scarce) literature shows that a resource curse may be underway in MENA economies. Broadly speaking, this literature often argues that the curse could be turned into a blessing through institutional improvements. The empirical data presented in this chapter tend to confirm this view. They show that the economic development of resource-rich MENAs has not been translated into human progress and has been largely non-inclusive. These results are stronger when the resource rent per capita is larger. Finally, the average institutional quality in resources-rich MENA countries appears to be lower than the average institutional quality in resources-poor MENA economies, suggesting some room for an institutional resource curse.
Keywords Institutions, Economic development, MENA, Natural resources curse
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Abstract We study infinitely repeated games in which players are limited to subsets of their action space at each stage—a generalization of asynchronous games. This framework is broad enough to model many real-life repeated scenarios with restrictions, such as portfolio management, learning by doing and training. We present conditions under which rigidity in the choice of actions benefits all players in terms of worst-case equilibrium payoff and worst-case payoff. To provide structure, we exemplify our result in a model of a two-player repeated game, where we derive a formula for the worst-case payoff. Moreover, we show that in zero-sum games, lack of knowledge about the timing of the revision can compensate for inability to change the action.
Keywords Exogenous timing, Commitment, Worst-case payoffs, Rational minimax, Asynchronous games
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