This paper proposes to evaluate tax reforms by aggregating money metric losses and gains of different individuals using “generalized social marginal welfare weights.” Optimum tax formulas take the same form as standard welfarist tax formulas by simply substituting standard marginal social welfare weights with those generalized weights. Weights directly capture society's concerns for fairness without being necessarily tied to individual utilities. Suitable weights can help reconcile discrepancies between the welfarist approach and actual tax practice, as well as unify in an operational way the most prominent alternatives to utilitarianism such as Libertarianism, equality of opportunity, or poverty alleviation.

We study the effect of top tax rates on “superstar” inventors' international mobility since 1977, using panel data on inventors from the US and European Patent Offices. We exploit the differential impact of changes in top tax rates on inventors of different qualities. Superstar inventors' location choices are significantly affected by top tax rates. In our preferred specification, the elasticity to the net-of-tax rate of the number of domestic superstar inventors is around 0.03, while that of foreign superstar inventors is around 1. These elasticities are larger for inventors in multinational companies. An inventor is less sensitive to taxes in a country if his company performs a higher share of its research there.