CU Denver Study: Most Americans Believe All Income Tax Levels Should Be 15%

The new research shows what Americans say is a fair share income tax

July 28, 2021

In a recently published studyUniversity of Colorado Denver Professor Emeritus Michael Roberts found most Americans believe a “fair share” of federal income taxes is 15%. The research was conducted alongside Theresa Roberts, a retired tax professional, and published in Advances in Taxation. 

Eight of every ten Americans surveyed say citizens of all income levels should pay 15% of their incomes to the federal government after the standard deduction allowed by the income tax law. The table below shows the difference this would make for both single and married taxpayers.  

Taxpayer Type  Income  Current Taxes  Suggested Taxes  
Single   $30,000  Approx. $2,500  Approx. $3,000 
Married  $190,000  Approx. $34,000  Approx. $27,000 

Participants judged “fair shares” of taxes for 10 hypothetical taxpayers after adjusting gross incomes to include government benefits received as determined by the independent Congressional Budget Office – $30,000 gross income for a single person to $189,000 gross income for a married couple.  

Seventy percent of participants assigned fair shares of income taxes proportionally to incomes above a standard deduction/exemption for married couple taxpayers, and 66% for unmarried individuals. This supermajority includes 79% of conservatives, 59% of liberals, and 75% of political neutrals, indicating bipartisan support for taxation proportional to incomes above the standard deduction.  

“The study was designed to test the extent to which political partisanship affects how people use fairness principles,” said Roberts. “This fairness is based on proportionality or relative contributions versus fairness based on perceived need.” 

More than 59% of self-identified political liberals assigned fair shares of income taxes consistent with a single (flat) 15% rate of tax above exempt income. Overall, fair shares of income tax assignments by 89% of the sample do not differ statistically when it comes to the income levels for unmarried individual taxpayers or for married couple taxpayers. These results indicate bipartisan support for reforming the federal income tax to reflect what 89% of citizens believe is a “fair share” is possible and that the electorate is not nearly as divided on this issue as public opinion polls—or our partisan political leaders—suggest.  

Based on examination of average tax rates between political ideology groups, researchers believe it is possible to construct a simple, single-rate income tax above a standard deduction and personal exemptions that reflects the income tax amounts 89% of Americans judge to be the “fair share.” 

“The results also demonstrate widespread misunderstanding about the effects of the current system of graduated or progressive federal income tax rates,” said Roberts. “This misunderstanding explains prior survey results purporting to show widespread support for graduated income tax rates among the public.” 

Seventy percent of participants in this study mistakenly identified an income tax consequence as “progressive” if a higher-income earner pays more tax dollars than a lower-income earner—even when the tax rates are actually regressive. This suggests any attempt to question the general public about fair assignments of tax “rates” may simply be producing pseudo-opinions and should not be relied upon for policymaking.  

The survey of 1,138 U.S. adults was conducted online among a sample selected to be representative of the U.S. population based on political affiliation. Based on the sample size, these results are valid within +/- 3 percent for a 95 percent confidence interval.