July 2002 <p> This paper presents a new approach to the old problem of linear dependency of age, cohort and time effects. It is shown that second differences of the effects can be estimated without any normalization restrictions, providing information on the shape of the age, cohort and time effect...</p>

March 2001 <p> “Open science" as a practise became increasing widespread in Europe during the late sixteenth and early seventeenth centuries. It represented a departure from the previously dominant ethos of secrecy in the pursuit of Nature’s Secrets, and its emergence was a distinctive and...</p>

December 19, 1999 (Revised) <p> At least three different "envelope theorems" have proved useful for economic analysis. One applies to unconstrained optimization problems with parameterized objectives and unique solutions, a second to constrained, smooth concave maximization problems in which both...</p>

Fall, 1997 Journal of Economic Perspectives, Volume 11, Number 4, pp.83-92, Fall 1997 <p> We advance a new perspective in the study of federalism. Our approach views federalism as a governance solution of the state to credibly preserving market incentives. Market incentives are preserved if the...</p>

September 1999 <p> Roberts' "weak neutrality" or "weak welfarism" theorem concerns Sen social welfare functionals which are defined on an unrestricted domain of utility function profiles and satisfy independence of irrelevant alternatives, the Pareto condition, and a form of weak continuity....</p>

IEA World Congress, December 1995

March 2003 <p> We introduce a two-sided matching model with contracts that subsumes and extends the Gale-Shapley matching model, the Kelso-Crawford labor market model and the Ausubel-Milgrom package auction model. We identify the maximal set of preferences over contracts for which a stable match...</p>

The lack of proper enforcement mechanism for sovereign debt generates a commitment failure. As a result, a sovereign may seek to improve its position in debt renegotiations and thus evade its debt obligations by reducing exports. Conditionality seeks to provide a solution to the incentive...

February 2001 <p> This paper studies decision problems under uncertainty where a decision-maker observes an imperfect signal about the true state of the world. We analyze the information preferences and information demand of such decision-makers, based on properties of their payoff functions. We...</p>