Etienne Lehmann

Should unemployment benefits decrease with the unemployment spell

In this paper, we investigate whether unemployment benefits should decrease with the unemployment spell in a model where both job search intensity and wages are endogenous. Wages are set by collective agreements bargained by insiders. It is shown that a more declining time sequence of unemployment benefits leads to wage increases when the tax rate is given. Such an effect may imply an increase in unemployment and counteracts the response of job search intensity that can be found in standard job search models with a given wage distribution. Calibration exercises suggest that it costs twice as much in terms of welfare loss for the long-term unemployed workers to reduce the unemployment rate by 1% when wages are endogenous than in the standard job search model.

Optimal Redistributive Taxation with Both Extensive and Intensive Responses

We derive a general optimal income tax formula when individuals respond along both the intensive and extensive margins and when income effects can prevail. Individuals are heterogeneous across two dimensions: their skill and their disutility of participation. Prefer-ences over consumption and work effort can differ with respect to the level of skill, with only the Spence-Mirrlees condition being imposed. Employing a new tax perturbation approach that integrates the nonlinearity of the tax function into the behavioral elasticities, we derive a fairly mild condition for optimal marginal tax rates to be nonnegative everywhere. Numerical simulations using U.S. data confirm the mildness of our conditions. The extensive margin strongly reduces the level of optimal marginal tax rates.

On the optimality of search matching equilibrium when workers are risk averse

This paper revisits the normative properties of search-matching economies when homogeneous workers have concave utility functions and wages are bargained over. The optimal allocation of resources is characterized first when information is perfect and second when search effort is not observable. In the former case, employees should be unable to extract a rent. The optimal marginal tax rate is then 100%. As search effort becomes unobservable, an appropriate positive rent is needed and the optimal marginal tax rate is lower. Moreover, the pretax wage is lower in order to boost labor demand. Finally, in both cases, nonlinear income taxation is a key complement to unemployment insurance.

Why will technical change not be permanently skill-biased?

We contribute to the debate on skill-biased technical change by studying the long-run dynamics of skill premia in an endogenous growth model in which technical change can be directed towards different factors. We show that R&D resources tend to be directed alternately towards skill-intensive and unskilled-intensive goods, creating cycles in skill premia. If resources were constantly directed towards the same sector, an innovation in a different sector would not be threatened by future innovators. Hence, researchers are incited to switch from one sector to another, in order to avoid the negative effect of innovations constantly occurring in the same sector.

L'IMPACT DE L'ASSURANCE CHOMAGE ET DE L'ASSISTANCE CHOMAGE SUR LE CHOMAGE D'EQUILIBRE

In this paper, I build a wage bargaining model to study the consequences of unemployment insurance and unemployment assistance on unemployment. I show that indexing the unemployment insurance benefit on the last wage earned increase the level of unemployment. I describe necessary conditions to avoid unemployment benefits to affect the level of unemployment. At last, we show that the effect of unemployment insurance on the unemployment rate depends on the concavity of the utility function.

Faut-il inciter l'offre ou la demande de travail peu qualifié?

We use dynamical job search matching framework to compare the effects of two policies targeted on low skilled jobs paid at a the minimum wage : reductions of employers’ contributions to social security versus reductions of taxes paid by employees such as the « Prime pour l’Emploi ». Our approach integrates simultaneously job search behaviour and frictional unemployment, contrary to previous literature. This type of model allows us to deal with effects of policies on unemployment rate, employment rate and welfare. Our results suggest that reducing employers contributions has larger effects on unemployment rate and unemployment spell, whereas redducing taxes paid by employees has larger effects on participation rates and welfare. Classification JEL : J64, J65