Firm size follows Zipf's Law, a very fat-tailed distribution that implies a few large firms account for a disproportionate share of overall economic activity. This distribution of firm size is crucial for evaluating the welfare impact of economic policies such as barriers to entry or trade...

Natives benefit from immigration mainly because of production complementarities between immigrant workers and other factors of production, and these benefits are larger when immigrants are sufficiently `different' from the stock of native productive inputs. The available evidence suggests that...

Default contribution rates for 401(k) pension plans powerfully influence workers' choices. Potential causes include opt-out costs, procrastination, inattention, and psychological anchoring. We examine the welfare implications of defaults under each of these theories. We show how the optimal...

This lecture examines the effects of tax policy and social security retirement benefits on capital accumulation and economic welfare. The paper begins by examining how capital income taxes reduce the real return to savers and then discusses the welfare loss of capital income taxation relative to...

We show that the welfare of a country's infinitely-lived representative consumer is summarized, to a first order, by total factor productivity (TFP) and by the capital stock per capita. These variables suffice to calculate welfare changes within a country, as well as welfare differences across...

This paper develops an analytical framework for the analysis of adjustment to adverse shocks in the presence of limited access to the international credit market. We consider an economy producing traded and non-traded goods and experiencing a permanent, unanticipated drop in the availability of...

I propose and formalize an argument for why economists working in the welfarist normative tradition should include nonwelfarist principles in how they judge economic policy. The key idea behind this argument is that the world is too complex, and our ability to model it too limited, for us to...

A common problem in applied economics is to determine the impact on consumers of changes in prices and attributes of marketed products as a consequence of policy changes. Examples are prospective regulation of product safety and reliability, or retrospective compensation for harm from defective...

We develop a framework to study analytically and quantitatively relentless cross-border casino competition with social-disorder and income-creation externalities. Two bordering casinos compete with each other for the external source of demand of recreational and problem gamblers from the...