Jerry Hausman presents evidence on the effects of income and payroll taxes on labor supply. Hausman emphasizes that while supply-side economics has focused attention on the labor supply and revenue effects of changes on tax rates, the correct measure of the economic cost of taxation is the deadweight loss associated with taxation. Hausman compares the implications of 10 percent and 30 percent tax cuts, along lines suggested by the Kemp-Roth tax proposal, with a move to a linear progressive tax system (i.e., one with progressive average tax rates but constant marginal tax rates). He finds that Kemp-Roth tax cuts decrease deadweight loss, but they do so at the expense of a large decline in tax revenue. A linear income tax that yields the same revenue as the current tax system, on the other hand, can significantly reduce deadweight loss as well as increase labor supply.