We use a simple graphical approach to represent Social Welfare Functions that satisfy Independence of Irrelevant Alternatives and Anonymity. This approach allows us to provide simple and illustrative proofs of May's Theorem, of variants of classic impossibility results, and of a recent result on...

This paper reviews the literature on governments' motivations for negotiating and joining international trade agreements. I discuss both normative explanations for trade agreements and explanations based on political-economy concerns. Most of the paper focuses on the purpose of multilateral...

We study a dynamic model of environmental protection in which the level of pollution is a state variable that strategically links policy making periods. Policymakers are forward looking but politically motivated: they have heterogeneous preferences and do not fully internalize the cost of...

We model visibility bias in the social transmission of consumption behavior. When consumption is more salient than non-consumption, people perceive that others are consuming heavily, and infer that future prospects are favorable. This increases aggregate consumption in a positive feedback loop....

Although most of the political-economy literature blames inefficient policies on institutions or politicians' motives to supply bad policy, voters may themselves be partially responsible by demanding bad policy. In this paper, we posit that voters may systematically err when assessing potential...

We face a variety of potential catastrophes; nuclear or bioterrorism, a climate catastrophe, and a "mega-virus" are examples. Martin and Pindyck (AER 2015) showed that decisions to avert such catastrophes are interdependent, so that simple cost-benefit analysis breaks down. They assumed that...

A new theoretical literature studies the use of capital controls to prevent financial crises in models in which pecuniary externalities justify government intervention. Within the same theoretical framework, we show that when ex-post policies such as defending the exchange rate can contain or...

I study expertise acquisition in a model of trading under asymmetric information. I propose and implement a method to estimate the ratio of social to private marginal value of expertise. This can be decomposed into three sufficient statistics: traders' average profits, the fraction of bad assets...

Should a social planner treat observationally identical persons identically? This paper shows that uniform treatment is not necessarily desirable when a planner has only partial knowledge of treatment response. Then there may be reason to implement a fractional treatment rule, with positive...

Attempting to shed light on the optimal size of government, economists have analyzed planning problems that specify a set of feasible taxation-spending policies and a social welfare function. The analysis characterizes the optimal policy choice of a planner who knows the welfare achieved by each...