A recent working paper by economists at the Congressional Budget Office (CBO) shows that not all taxes are created equal—progressive taxes on labor income and taxes on capital income would have a negative impact on the economy, capital investment, and jobs, especially when compared to flatter taxes on labor income. Policymakers should consider these results as they debate ways to fund additional spending. There are many ways to raise an additional dollar of revenue, but some methods do more damage to long-run growth by undermining incentives to work and invest.

The CBO examined three tax increases to raise 5 percent or 10 percent of GDP in additional revenue: a flat tax on labor earnings, a flat tax on income from labor and capital, and a progressive income tax.

A tax on labor income is like levying an additional payroll tax on wages and self-employment earnings, while taxes on capital income apply to income sources like capital gains and dividends. To measure the effect of progressive taxes, the CBO also modeled a proportionate increase in tax rates on labor combined with a flat tax on capital income.

The authors find that labor taxes are less economically harmful than taxes on capital, as capital is more mobile and sensitive to taxation. For example, a labor tax raising 5 percent of GDP in revenue would reduce GDP by 3.2 percent in 2030, while a progressive income tax would reduce GDP by 4.5 percent. Progressive income taxes are more damaging to growth because “high-productivity workers reduce their hours worked and because higher taxes on asset income reduce the incentive to save and invest relatively more than under the two flat taxes.”

We find broadly similar results when using the Tax Foundation General Equilibrium model, namely that progressive income taxes are the most economically damaging of the three options. We find that a progressive income tax of 5 percent of GDP would reduce long-run GDP by 3.4 percent, shrink American incomes (GNP) by 3.8 percent, and eliminate about 3.6 million jobs. We find that a flat labor tax of 5 percent of GDP would reduce long-run GDP and GNP by 2.2 percent and eliminate about 2.4 million jobs.

Some Tax Hikes Are More Damaging Than Others

For our results, a “flat labor tax” applies a payroll tax to labor income while not impacting investment income. A flat income tax imposes a flat surtax onto each tax bracket for ordinary income and long-term capital gains and dividends, while the progressive income tax applies proportionate increases to ordinary income tax rates and long-term capital gains and dividends rates.

Tax increases on labor reduce total hours worked by reducing the after-tax return to labor, while capital income taxes harm investment incentives. As the CBO states, “the less a tax distorts people’s decisions to work, save, and invest, the smaller the economic effects are per dollar of revenues raised. As any tax rate increases, the size of the resulting economic distortion grows.”

Raising taxes to increase revenue by 10 percent of GDP would have larger economic effects. According to Tax Foundation modeling, a progressive income tax is the most damaging option, reducing GDP by 6.5 percent, shrinking American incomes (GNP) by 7.3 percent, and eliminating about 6.7 million jobs. We find that a flat labor tax of 10 percent of GDP would reduce long-run GDP by 4.4 percent and GNP by 4.5 percent and eliminate about 5 million jobs.

For our results, a “flat labor tax” applies a payroll tax to labor income while not impacting investment income. A flat income tax imposes a flat surtax onto each tax bracket for ordinary income and long-term capital gains and dividends, while the progressive income tax applies proportionate increases to ordinary income tax rates and long-term capital gains and dividends rates.

Using the Tax Foundation’s model to simulate a higher corporate income tax indicates that this would be more damaging to economic growth than the three options above. For example, raising the corporate income tax to generate 5 percent of GDP in additional revenue would reduce long-run GDP by 11.3 percent.

The results from the CBO and Tax Foundation models show that, independent of spending, the type of tax used to finance the spending matters. Policymakers should consider how damaging a given tax increase would be for economic growth and American jobs, not just its impact to the Treasury. Selecting less damaging revenue sources and avoiding dramatic tax increases will contribute to a successful U.S. economic recovery over the coming year.