Publications
We compare distributions of body mass index (BMI) categories among genders in France, the United States, and the United Kingdom on the basis of efficiency and inequality considerations. The new normative criteria that we propose are well suited to the ordinal nature of this variable. Our empirical results, which are supported by robust statistical inference, are twofold. First, BMI categories for the two genders are better distributed in France than in the UK, and in the UK than in the US. Second, BMI categories happen to be more equally distributed among men than among women in all three countries.
This paper provides a tool to build climate change scenarios to forecast Gross Domestic Product (GDP), modelling both GDP damage due to climate change and the GDP impact of mitigating measures. It adopts a supply-side, long-term view, with 2060 and 2100 horizons. It is a global projection tool (30 countries/regions), with assumptions and results both at the world and the country/regional level. Five different types of energy inputs are taken into account according to their CO2 emission factors. Full calibration is possible at each stage, with estimated or literature-based default parameters. Compared to other models, it provides a comprehensive modelisation of Total Factor Productivity (TFP), which is the most significant determinant of the GDP projected path. We present simulation results of different energy policy scenarios. They illustrate both the “tragedy of the horizon” and the “tragedy of the commons”, which call for a policy framework that adequately integrates a long run perspective, through a low-enough discount rate and an effective intergenerational solidarity as well as international cooperation.
Using a change in EU food aid policy in 1996 as an instrument for EU food aid allocation, I investigate how other donors react to the EU’s food aid allocation. At that time, the EU suddenly divided by two the number of its food aid recipients. On average, other donors imitate the EU at both extensive and intensive margins. Donors’ reactions are heterogeneous: European countries and Canada herd the EU, while the World Food Programme substitutes. The USA do not react. Those results can be explained by competition for relative impact and information effects. For a recipient country who constantly received food aid from the EU before 1996, the number of donors decreases by almost 0.5. This behavior reinforces the problem of orphan and darling recipients.
This paper has two aspects. Mathematically, in the context of global optimization, it provides the existence of an optimum of a perturbed optimization problem that generalizes the celebrated Ekeland variational principle and equivalent formulations (Caristi, Takahashi), whenever the perturbations need not satisfy the triangle inequality. Behaviorally, it is a continuation of the recent variational rationality approach of stay (stop) and change (go) human dynamics. It gives sufficient conditions for the existence of traps in a changing environment. In this way it emphasizes even more the striking correspondence between variational analysis in mathematics and variational rationality in psychology and behavioral sciences.
