A recent Ernst & Young study concluded that the tax-rate increases on high-income taxpayers proposed by President Barack Obama would hurt small-business investment and the economy.

Another recent study by the Tax Policy Center found that under Mitt Romney's proposed tax reform, the rich would pay less and everyone else would pay more.

Republicans, of course, cheered the first study and booed the second. Democrats did the reverse.

In actuality, both studies provide reality checks that shouldn't be ignored.

According to Obama, he is just proposing returning income-tax rates for those making over $200,000 a year to what they were under Bill Clinton, when the economy was humming. So, what's to worry?

That's a false claim. "Obamacare" already enacted an increase in the Medicare payroll-tax rate for the affluent and subjected their investment income to it for the first time. So, Obama is proposing tax rates higher than existed during the Clinton presidency. And it's worth noting that while still president, Clinton said he thought he had raised the rates too high.

Obama's tax increases on investment income are also a much more radical departure from the status quo than were Clinton's. (The capital-gains tax rate was actually reduced during Clinton's presidency.) That will make their effect on investment decisions larger.

Under Obama's proposals, the top tax rate on ordinary income would go up by 6 percentage points. The rate on capital gains would increase nearly 10 percentage points. The top rate on dividend income would soar by nearly 30 percentage points.

These huge tax increases would disproportionately hit the nation's most productive small businesses because they frequently have forms of business organization in which the company's profits flow through to the owners and are taxed at the individual rates. A substantial portion of the taxes collected under the higher rates would be on flow-through small-business profits.

Ernst & Young projects that the Obama tax increases would result in $200 billion less economic output and 710,000 fewer jobs. It estimates adverse effects for individual states. Arizona, for example, would purportedly suffer $3.5 billion in lower output and have 13,000 fewer jobs.

These specific numbers should be taken with a grain of salt. They result from yet another macroeconomic model, which spit out results with unwarranted precision.

Nevertheless, a little common sense goes a long way. If $70 billion a year, which is what Ernst & Young estimates to be the annual cost of all the Obama tax increases, is taken out of the private-sector economy to fund government, the private sector will perform less well. And if tax rates on investment income are substantially increased, there will be less investment.

Mitt Romney says he will reduce individual tax rates across the board, returning the top rate to the 28 percent it was under Ronald Reagan. He also says he would make the rate reductions revenue-neutral, with no net cost to the Treasury, by ending credits and deductions.

Romney doesn't specify which credits and deductions he would eliminate. Regardless, the Tax Policy Center study argues it can't be done without making the income-tax code more regressive. That's because those making less than $200,000 a year get proportionally more benefit from the largest credits and deductions than those making more.

There is one phenomenon the center fails to take sufficient account of. The affluent have considerable discretion about when and how they realize income. And the lower the rates, the more income they are willing to realize.

Nevertheless, lowering rates and maintaining revenue-neutrality will require the slaughter of sacred credit and deduction cows. The money is in politically popular categories such as untaxed health-care benefits, mortgage interest, charitable contributions and state and local taxes.

Obama's tax increases would shrink investment capital, particularly among small businesses. Romney is not leveling with the American people about the full implications of his proposed tax reform.

These aren't really dueling tax studies. They both frame unpleasant realities the candidates and partisans want to ignore.

Reach Robb at robert.robb @arizonarepublic.com.