Publications des chercheurs de PSE

The paper identifies a necessary and sufficient condition for a deterministic local optimum to be locally improved upon by a stochastic deviation. When this condition is satisfied, a method to construct the stochastic allocations that increase the objective is provided. This technique is applied to a number of adverse selection and moral hazard problems.

A government designs anonymous income transfers between a continuum of citizens whose income valuation is privately known. When transfers are deterministic, the incentive constraints imply equal treatment independently of the government's taste for redistribution. We study whether random transfers may locally improve upon the egalitarian outcome. A suitable Taylor expansion offers an approximation of the utility function by a quasilinear function. The methodology developed by Myerson to deal with incentive constraints then yields a necessary and sufficient condition for the existence of a socially useful randomization. When this condition is met a large set of lotteries are locally improving. A special menu made of two lotteries only is of interest: all the agents with low risk aversion receive the same random transfer, financed by a deterministic tax paid by the high risk aversion agents.

Consider a simple general equilibrium economy with one representative consumer, a single competitive firm and the government. Suppose that the government has to finance public expenditures using linear consumption taxes and/or a lump-sum tax on profits redistributed to the consumer. This note shows that, if the tax rate on profits cannot exceed 100 percent, one cannot improve upon the second-best optimum of an economy with constant returns to scale by using a less efficient profit-generating decreasing returns to scale technology.

We put forward a method for estimating discount rates using wealth and income data. We build consumption from these data using the budget constraint. Consumption transitions yield discount rates by household groups. Applying this technique to a sample of older households, we find a similar distribution to those previously estimated using field data, though with a much lower mean than those found using experiments. Surprisingly, among this older population, patience is negatively correlated with education and numeracy. This goes against the positive correlation found for younger populations in experiments and some field studies. We discuss potential explanations for this result.

A model of labour supply and taxation is developed in which observed hours reflect both the distribution of preferences and restrictions on choices. Hours restrictions are placed in a constrained rational choice setting in which the set of alternative hours on offer is restricted. Choices are made on a random subset of possible hours. We focus on the case where the choice set contains at most two offers. We show that when the choice set distribution is known, preferences can be identified. Conversely we show that, where preferences are known, the choice set distribution can be fully recovered. Conditions for identification of both preferences and the distribution of choice sets are also developed. We illustrate this approach in a labour supply setting with nonlinear budget constraints. Heterogeneity in the budget constraint reveals properties of the choice set. This framework is used to study the labour supply behaviour of a large sample of working age mothers in the UK, accounting for nonlinearities in the tax and welfare benefit system, fixed costs of work and restrictions on hours choices.

Consider a simple general equilibrium economy with one representative consumer, a single competitive firm and the government. Suppose that the government has to finance public expenditures using linear consumption taxes and/or a lump-sum tax on profits redistributed to the consumer. We show that, if the tax rate on profits cannot exceed 100 percent, one cannot improve upon the second-best optimum of an economy with constant returns to scale by using a less efficient profit-generating decreasing returns to scale technology.

This paper assesses the usefulness of stochastic contracts in the presence of informational asymmetries. It identifies circumstances where a stochastic redistribution policy is socially dominated by the deterministic policy where after-tax income lotteries are replaced with their certainty equivalent. It also provides a parametric example where every stochastic menu which has the optimal deterministic menu as certainty equivalent is dominated by the deterministic menu, while there exist feasible and incentive compatible lotteries improving locally upon the deterministic menu.