Economists traditionally tackle normative problems by computing optimal policy, i.e. the one that maximizes a social welfare function. In practice, however, a succession of marginal changes to a limited number of policy instruments are implemented, until no further improvement is feasible. I...

This paper studies aggregate dynamics in a cobweb model where learning takes place through a selection mechanism, by which more successful firms are replicated at a higher rate. The structure of the model allows to characterize analytically the aggregate dynamics, and to compute the effect on...

When policymakers and private agents use models, the economists who design the model have an incentive to alter it in order to influence outcomes in a fashion consistent with their own preferences. I discuss some consequences of the existence of such ideological bias. In particular, I analyze...

We study active labor market policies (ALMP) in a matching model. ALMPs are modelled as a subsidy to job search. Workers differ in their productivity, and search takes place along an extensive margin. An additional job seeker affects the quality of unemployed workers. As a result, the Hosios...

Utilitarian foundations for limited government are shaky insofar as they assume rational and consistent individuals. Recently economists' assumption of rational actors has come under sustained attack. Behavioural economics has suggested that people are plagued by irrational biases and...

We develop a theory of endogenous political entrenchment in a simple two-party dynamic model of income redistribution with probabilistic voting. A partially self-interested left-wing party may implement (entrenchment) policies reducing the income of its own constituency, the lower class, in...

Trade liberalization is often met with sharp opposition. Recent examples include the so-called "Bolkestein" directive, which allows service providers from a given EU member to temporarily work in another member country. One way to view such a reform is that it simply widens the range of goods...

This paper studies how an institution such as markets affects the evolution of mankind. My key point is that the forces of natural selection are made weaker because trade allows people to specialize in those activities where they are strong, and to offset their weaknesses by purchasing adequate...

This paper analyses the welfare effects of price restrictions on private contracting in a world where agents have a limited cognitive ability. People compute the costs and benefits of entering a transaction with an error. The government knows the distribution of true costs and benefits as well...

In this paper, I analyze the pros and cons of implementing structural reforms of the labor market in booms vs. recessions, in light of considerations of social efficiency, political viability, and macroeconomic fine tuning. While the optimal timing of a reform depends on the relative importance...