Even amoebas learn by trial and error, but some economists and politicians do not. The Obama administration's budget projections claim that raising taxes on the top 2% of taxpayers, those individuals earning more than $200,000 and couples earning $250,000 or more, will increase revenues to the U.S. Treasury. The empirical evidence suggests otherwise. None of the personal income tax or capital gains tax increases enacted in the post-World War II period has raised the projected tax revenues.
Over the past six decades, tax revenues as a percentage of GDP have averaged just under 19% regardless of the top marginal personal income tax rate. The top marginal rate has been as high as 92% (1952-53) and as low as 28% (1988-90). This observation was first reported in an op-ed I wrote for this newspaper in March 1993. A wit later dubbed this "Hauser's Law."
Over this period there have been more than 30 major changes in the tax code including personal income tax rates, corporate tax rates, capital gains taxes, dividend taxes, investment tax credits, depreciation schedules, Social Security taxes, and the number of tax brackets among others. Yet during this period, federal government tax collections as a share of GDP have moved within a narrow band of just under 19% of GDP.
Why? Higher taxes discourage the "animal spirits" of entrepreneurship. When tax rates are raised, taxpayers are encouraged to shift, hide and underreport income. Taxpayers divert their effort from pro-growth productive investments to seeking tax shelters, tax havens and tax exempt investments. This behavior tends to dampen economic growth and job creation. Lower taxes increase the incentives to work, produce, save and invest, thereby encouraging capital formation and jobs. Taxpayers have less incentive to shelter and shift income.
On average, GDP has grown at a faster pace in the several quarters after taxes are lowered than the several quarters before the tax reductions. In the six quarters prior to the May 2003 Bush tax cuts, GDP grew at an average annual quarterly rate of 1.8%. In the six quarters following the tax cuts, GDP grew at an average annual quarterly rate of 3.8%. Yet taxes as a share of GDP have remained within a relatively narrow range as a percent of GDP in the entire post-World War II period.