Measuring Revenue-maximizing Elasticities of Taxable Income

Abstract

This article considers the question of whether marginal tax rates (MTRs) in the US income tax system are on the “right” side of their respective Laffer curves. Previous attention has tended to focus specifically on the top MTR. Conceptual expressions for these “revenue-maximizing elasticities of taxable income” (ETI L), based on readily observable tax parameters, are presented for each tax rate in a multi-rate income tax system. Applying these to the US income tax, with its complex effective marginal rate structure, demonstrates that a wide range of revenue-maximizing ETI values can be expected within, and across, tax brackets and for all taxpayers in aggregate. For some significant groups of taxpayers, these revenue-maximizing ETIs appear to be within the range of empirically estimated elasticities.