View original document

The full text on this page is automatically extracted from the file linked above and may contain errors and inconsistencies.

Home / Publications / Research / Economic Brief / 2024

How Can We Make a Progressive Tax System More
E cient?
By Marios Karabarbounis

Economic Brief
Aug ust 2024, No. 24-26

Key T akeaways
In a progressive tax system, taxes as a share of income increase as income
increases.
A progressive tax system reduces inequality but also diminishes the incentive for
individuals to strive for higher incomes.
I discuss ways to maintain a progressive tax system without imposing such
disincentives on workers.

In the U.S., income tax rates rise as households earn more. However, such a system means
workers have a reduced incentive to increase their earnings. In this article, I discuss a
nding from one of my papers that explores the possible e ects of targeting tax rates on
additional characteristics besides income.

The U.S.'s Progressive Income Tax System
Federal income taxes are the primary source of revenue for the federal government.
According to estimates from 2022, 54 percent of federal revenues came from individual
income taxes, 30 percent from Social Security taxes, 8 percent from corporate income
taxes, and the remaining from other types of taxation such as estate taxes.1
A fundamental characteristic of the U.S. income tax system is its progressivity. A tax system
is considered progressive if the tax burden as a share of income rises as income increases.
For example, in a progressive tax system, a family with an income of $100,000 might pay a
/

total of 20 percent in taxes, while a family with an income of $200,000 might pay a total of
25 percent of its income in taxes.
In contrast, a proportional (or at) tax system maintains a constant tax rate regardless of
income, and a regressive tax system decreases the tax rate as income rises. T he degree of
progressivity is linked to the concept of vertical equity, which concerns how the tax burden
is distributed among households with di erent levels of well-being.

Income Inequality and the U.S. Tax System
Many view a progressive tax system as fair because an extra dollar holds less value for a
high-income household than for a low-income household. T herefore, asking higherincome households to contribute a larger fraction of their additional income is seen as a
reasonable policy. However, some argue it is unfair to require certain taxpayers to pay
more than others or pay a larger share of their income.
One principle guiding economists in evaluating tax policy fairness is the bene t principle,
which suggests that the tax burden should correspond to the bene ts received from
government services. Based on this principle, it is argued that higher-income individuals —
who bene t from public infrastructure and government spending — should contribute
more signi cantly to the tax burden.
T he public discussion about how progressive the tax system should be is often motivated
by the rise in income inequality. T he top 10 percent of earners in the U.S. now receive
around 45 percent of national income, up from 35 percent 50 years ago.2 Economist
T homas Piketty attributes this rise in inequality primarily to an unprecedented increase in
wage disparity, stemming from the income rise of top executives and managers.3
Of course, inequality itself may not be problematic if there is su cient economic mobility.
For instance, if low-income and high-income workers frequently change places, income
inequality is less concerning. However, mobility at the top of the income distribution has
remained stable, not o setting the rise in inequality since the 1970s.4
T axes can also impose hidden economic costs. When high-income levels are taxed more
heavily, it can diminish the incentive for individuals to strive for higher incomes. Conversely,
if everyone pays the same amount of taxes, there is no disincentive to work harder, as
one's e orts do not a ect the amount of tax paid. Every economic tax system needs to
resolve this trade-o : A more progressive tax system may reduce income inequality but
often imposes larger disincentives to economic agents.

A More E cient Income Tax System?
A basic principle of public nance is that the government should decrease tax distortions
on workers who are more likely to respond adversely to a rise in their taxes. (In economics
jargon, these would be workers with a larger value of labor supply elasticity.)

/

But how can the government distinguish between workers with a low or high elasticity of
labor supply? In my 2016 paper "A Road Map for E ciently T axing Heterogeneous Agents,"
I propose using information on the observable characteristics of the workers. For example,
workers closer to retirement are more likely to quit their jobs if their taxes increase. Also,
secondary earners in dual-income households may be the rst to drop out of the labor
market if their taxes increase.
So, how could a more e cient tax system work? T hink of an economy with 10 potential
workers. Each worker has a wage level that makes the worker exactly indi erent between
participating in or staying out of the labor market. And this "reservation wage" is not the
same across workers. For example, young workers may be willing to work for lower wages
to build experience and skills. Other workers may not accept a job unless it is high paying,
such as workers with enough accumulated assets or nancial support who can a ord to
stay out of the labor force.
Let's rank workers in terms of reservation wages from bottom to top and consider a
company that o ers a wage equal to the reservation wage of worker 5. How many workers
can the company attract? Workers 1 to 4 would happily accept the job position, worker 5
would be just indi erent about accepting, and workers 6 to 10 would decline to work.
Now, imagine that the government levies taxes of 1 percent of workers' labor income.
T hese taxes e ectively reduce the (after-tax) wage received by the workers. As a result,
worker 5 now also rejects the o er, so the company's pool of workers becomes even
smaller.
But there is a way to impose taxes while also keeping worker 5 in the workforce: increase
taxes only on workers 1 to 4. T his tax system would keep taxes low for workers who are
the most likely to respond to a lower after-tax wage (worker 5 in our example).
How can such a tax system be implemented in practice? Since labor supply elasticity is
unobservable, the government can rely on information on workers' age and wealth
holdings, which are strong predictors of how low or high workers' reservation wages are.

Summary of Findings
In my paper, I evaluate the potential of a tax system that explicitly depends on such
characteristics. I nd that, regarding age, the tax rates should be lower for young and old
households and higher for mid-career households. T ax rates should additionally decrease
in household assets and as households get closer to retirement. Finally, I suggest that
when a spouse joins the workforce, households should get a tax credit. Using a
quantitative model, I nd that these reforms have signi cant economic gains: Capital
increases by up to 20 percent, and labor supply increases by up to around 3 percent.

/

Marios Karabarbounis is a senior economist in the Research Department at the Federal
Reserve Bank of Richmond.

1 See the 2023 article "Your Income Taxes Are Due. Here's Who Pays the Most." by Laura

Saunders.
2 See the 2017 paper "Distributional National Accounts: Methods and Estimates for the United

States" by Thomas Piketty, Emmanual Saez and Gabriel Zucman.
3 See Piketty's 2013 book Capital in the 21st Century.
4 See the 2010 article "Earnings Inequality and Mobility in the United States: Evidence from Social

Security Data Since 1937" by Wojciech Kopchuk, Emmanuel Saez and Jae Song.

To cite this Economic Brief, please use the following format: Karabarbounis, Marios. (August
2024) "How Can We Make a Progressive T ax System More E cient?" Federal Reserve Bank of
Richmond Economic Brief, No. 24-26.

T his article may be photocopied or reprinted in its entirety. Please credit the author,
source, and the Federal Reserve Bank of Richmond and include the italicized statement
below.
Views expressed in this article are those of the author and not necessarily those of the Federal
Reserve Bank of Richmond or the Federal Reserve System.

Topics
Economic Inequality and Poverty

Fiscal Policy

Employment and Labor Markets

Subscribe to Economic Brief
Receive a noti cation when Economic Brief is posted online.
By submitting this form you agree to the Bank's Terms & Conditions and Privacy Notice.
/

Email Address

Subscribe

Contact Us
RC Balaban
(804) 697-8144

© 1997-2024 Federal Reserve Bank of Richmond

/