Publications

We investigate the divergence in risk preferences between individuals exposed to background risk and those who are not, using a field experiment conducted in Arequipa, Peru. Arequipa, a city located in close proximity to the El Misti volcano, is constantly threatened by lahars – mudflows originating from this volcano. Our study combines experimental assessments of risk tolerance and patience with a targeted survey designed to assess residents' awareness of their exposure to risks. Our primary finding reveals that residents living in hazard-prone areas exhibit higher levels of risk tolerance compared to their counterparts in safer zones. To address concerns about causality, we employ instrumental variable (IV) regressions and conduct stability analyses of coefficients. We subsequently discuss our findings in the context of the literature on preference adaptation 

It has been shown that living in risky environments, as well as having a risky occupation, can moderate risk-tolerance. Despite the involvement of dopamine in the expectation of reward described by neurobiologists, a GWAS study was not able to demonstrate a genetic contribution of genes involved in the dopaminergic pathway in risk attitudes and gene candidate studies gave contrasting results. We test the possibility that a genetic effect of the DRD4-7R allele in risk-taking behavior could be modulated by environmental factors. We show that the increase in risk-tolerance due to the 7R allele is independent of the environmental risk in two populations in Northern Senegal, one of which is exposed to a very high risk due to dangerous fishing.

Résumé: Les inégalités d'accès à la santé constituent une préoccupation majeure des pouvoirs publics dans les pays en voie de développement. Dans ce document, nous cherchons à comprendre les sources de ces inégalités en utilisant une base de données d'enquête du DHS de 12 pays d'Afrique Sub-Saharienne (Bénin, Ethiopie, Ghana, Kenya, Libéria, Mali, Guinée, Nigéria, Sierra-Léone, Sénégal, Togo et Zambie). Après avoir mesuré leur degré d'inégalité à travers l'indice de concentration, nous avons employé une méthode récemment proposée par Wagstaff et al. (2003) pour décomposer cette inégalité en part "expliquée" par la contribution de ses facteurs déterminants et en composante résiduelle (ou effet "richesse" pur ou part "inexpliquée"). Les résultats ont montré que les facteurs déterminants contribuent à l'inégalité à des parts qui varient de 11 à 89%, selon les pays. Les variables qui contribuent le plus à l'inégalité "expliquée" sont l'éducation et les différences de milieux (urbain/rural) avec des parts respectives de 38,5 et 56%. Autrement dit, si la richesse avait été distribuée de manière égale, les inégalités en matière de santé resteraient en grande partie à cause des inégalités liées d'éducation et de milieux urbains et ruraux. 

Abstract: Two important lines of research have shaped our understanding of the ability of communities to engage in collective action. The first proposes ethnic division as a key determinant, with more ethnically-heterogeneous countries having worse economic performance and fewer public goods. The second focuses on social capital as a major determinant of the ability to engage in collective action. We expect trust among community members, a widely-used measure of social capital, to be an important and positive determinant of school quality. We find a large positive effect of trust on practical aspects of schooling, such as maintaining buildings or providing textbooks. In sharp contrast, ethnic fractionalization is found to have a very limited effect, if any. We propose a simple model of public-good provision that explores a channel by which social capital and ethnic division may (or may not) affect the provision of local public good such as schools. 

Abstract: The goal of this paper is to investigate the impact of trust on individuals’ decisions to participate in collective activities in rural Senegal. For this purpose, a version of the trust game in which subjects are matched with a random anonymous member of their own community is designed. Results are compared to survey trust questions: the World Value Survey trust question and specific questions regarding trust in neighbors and trust in strangers. Results show that trust, as measured by survey questions, has poor predictive power, while the results from a simple trust game are much better predictors of local participation in collective activities. More particularly, a one-unit change in the amount sent increases the odds of participation in Tontine, Credit Association and Animation by 2.3 percent, 2.6 percent and 1.7 percent, respectively. Furthermore, we find that individuals who consider that ‘most people can be trusted’ have 17.58 percent more chance to participate in Animation activities. 

Abstract: We test for a causal role of social capital, as measured by self-reported trust, in determining access to basic health facilities in Sub-Saharan Africa. To skirt the reverse-causality problems between social capital and basic health, we rely on instrumental-variable (IV) estimates. A one standard-deviation increase in trust is predicted to lead to a 0.22 standard-deviation fall in doctor absenteeism, a 0.31 standard-deviation fall in waiting time and a 0.30 standard-deviation fall in bribes. As a robustness check, we also use a different database regarding a different health issue, access to clean water. We find that a one standard-deviation rise in trust leads to a 0.33 standard-deviation rise in access to clean water. The variety of public goods considered provides insights about the possible channels through which social capital is converted into health improvements. . 

Résumé: Le 12 octobre 2009 Elinor Ostrom recevait le Prix Nobel d’économie pour sa contribution à l’analyse des biens collectifs. Cet article se propose de dresser un panorama de ses travaux. Nous commencerons par retracer l’itinéraire académique et professionnel d’Ostrom. Dans une deuxième partie, nous verrons comment elle mobilise successivement différentes méthodes d’investigation tout au long d’un itinéraire qui part de l’étude minutieuse de multiples situations concrètes pour évoluer vers des recommandations de politiques publiques pour le compte de grands organismes internationaux. En conclusion, nous évoquerons les implications qu’elle tire de son travail pour contribuer à un renouvellement des théories de la rationalité.