A long-standing challenge for welfare economics is to develop welfare criteria that can be applied to allocations with different population levels. Such a criterion is essential to resolve the optimal population problem, i.e., the tradeoff between population size and the welfare of each person...

Just like any trade activity in well-functioning markets, migration tends to enhance the efficiency of the allocation of resources. With non-distortionary income distribution policy instruments which can compensate losers, migration generates income gains. But the gains tend to be typically...

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...

Market provision of impure public goods such as insurance retirement savings and education is common and growing as policy makers seek to offer more choice and gain efficiencies. This approach induces an important trade-off between improved surplus from matching individuals to products and...

Specialized theoretical and empirical research should in principle be embedded in a unified framework that identifies the relevant interactions among different phenomena, enables an appropriate matching of policy instruments to objectives, and grounds normative analysis in individuals’...

In this paper we develop an approach to measuring inequality and poverty that recognizes the fact that individuals within households may have both different preferences and differential access to resources. We argue that a measure based on estimates of the sharing rule is inadequate as an...

Globalization radically changes income distribution and triggers intense international tax competition. Therefore, globalization entails an extensive restructuring of the welfare state. We analyze a parsimonious model of an open economy, in its trade and finance transactions with the rest of the...

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...