This paper presents evidence on taxable income responses using administrative data that link tax return information to detailed socioeconomic information for the full Danish population over 25 years. The identifying variation is provided by a series of tax reforms that create large tax variation...

Starting with Mirrlees (1971) and Vickrey (1945), the optimal tax literature has studied the design of a personal income tax. The ideal would be to tax earnings ability. Earnings ability is unobservable for tax purposes, however, and past papers have focused instead on designing a tax on labor...