The impact of ambiguity on health prevention and insurance.

In this paper, we analyze the choice of primary prevention made by individuals who bear a risk of being in bad health and an additive risk (of complications) that occurs after a disease has been diagnosed. By considering a two argument utility (depending on wealth and health), we show that the presence of a well-known (no ambiguity) additive risk of complications induces more investment in primary prevention by a risk-averse agent only if her preferences does not display some cross prudence in wealth (u122 0). We also show that full (partial) insurance can be optimal even if insurance premia are loaded (fair). These results hold with and without prevention and the individuals attitudes toward correlation help explain the impact of ambiguity on the optimal individual decisions.health; utility; ambiguity; prevention; insurance.

Bankable emission permits under uncertainty and optimal risk-management rules.

This article proposes a theory of banking of emission permits under conditions of regulatory uncertainty. Based on a two-period partial equilibrium framework, we examine the effects of increasing risk - in the sense of a mean-preserving spread - regarding a future permits allocation at the firm-level. We also examine the role of an agency to pool risks by re-allocating permits for a group of firms. Our results are twofold. First, an increase in risk may lead to changes in a firm’s banking strategy, depending on the third partial derivative of its production function with respect to pollution. Second, we define an optimal risk-sharing rule between agents to respond to political decision changes. Our results overall suggest that the bankability of permits may be used as a risk-management tool.Banking; Emission permits; Policy risk; Uncertainty;

A benchmark value for relative prudence

In this paper we propose benchmark values for the coefficients of relative risk aversion and relative prudence on the basis of a binary choice model where the decision maker chooses between aggregating or disaggragating multiplicative risks. We relate our results to the decison maker's willingness to trade-off the second with the first and the third (central) moment of his wealthdistribution.relative risk aversion, relative prudence

Decision theory under uncertainty

We review recent advances in the field of decision making under uncertainty or ambiguity.Ambiguity ; ambiguity aversion ; uncertainty ; decision

«The Falling Sperm Counts Story»: A Limit to Growth?

We develop an overlapping generations model of growth, in which agents differ through their ability to procreate. Based on epidemiological evidence, we assume that pollution is a cause of this health heterogeneity, affecting sperm quality. Nevertheless, agents with impaired fertility may incur health treatments in order to increase their chances of parenthood. In this set-up, we analyse the dynamic behaviour of the economy and characterise the situation reached in the long run. Then, we determine the optimal solution that prevails when a social planner maximises a Millian utilitarian criterion and propose a set of available economic instruments to decentralise the optimal solution. We underscore that to correct for both the externalities of pollution and the induced-health inefficiency, it is necessary to tax physical capital while it requires to overall subsidy mostly harmed agents within the economy. Hence, we argue that fighting against the sources of an altered reproductive health is more relevant than directly inciting agents to incur health treatments

The Alestle - Vol. 59 No. 51 - 03/29/2007

Vol. 59 No. 5

Illiquid Life Annuities

In this article, we consider illiquid life annuity contracts and show that they may be preferred to Yaari (1965)’s liquid contracts. In an overlapping-generation economy, liquid life annuities are demanded only if the equilibrium is dynamically inefficient. Alternatively, an equilibrium displaying a positive demand for illiquid life annuities is efficient. In this latter case, the welfare at steady-state is larger if illiquid life annuity contracts are available

Illiquid Life Annuities

In this article, we consider illiquid life annuity contracts and show that they may be preferred to those illustrated by Yaari (1965). In an overlapping-generation economy, liquid life annuities are demanded only if the equilibrium is dynamically inefficient. Conversely, an equilibrium displaying a positive demand for illiquid life annuities is efficient. In this latter case, the welfare at steady-state is larger if illiquid life annuity contracts are available

Illiquid Life Annuities

In this article, we consider illiquid life annuity contracts and show that they may be preferred to those illustrated by Yaari (1965). In an overlapping-generation economy, liquid life annuities are demanded only if the equilibrium is dynamically inefficient. Conversely, an equilibrium displaying a positive demand for illiquid life annuities is efficient. In this latter case, the welfare at steady-state is larger if illiquid life annuity contracts are available

Les effets d’un risque démographique sur l’épargne.

Cet article étudie les effets sur l'épargne d'une incertitude sur le taux de croissance de la population dans un modèle à générations imbriquées. Nous montrons que les hypothèses nécessaires à la formation d'une épargne individuelle de précaution ne suffisent pas dans un cadre d'équilibre général. Le motif de précaution ne permet plus à lui seul ainsi de déterminer l'influence d'un accroissement du risque sur l'épargne d'équilibre.