Joint 

Committee on 

Taxation

Edward D. Kleinbard

Chief of Staff

Joint Committee on Taxation

Reading JCT Staff Distribution Tables:

An Introduction to Methodologies

and Issues

December 9, 2008
Joint 

Committee on 

Taxation

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What is Distributional Analysis?

Distributional analysis is the study of how a tax system’s aggregate 

costs and economic burdens are shared by taxpayers, taking into 

account their different incomes, consumption, etc.

The subject is vitally important to policymakers, who wish to 

ensure that a tax system satisfies their visions of fairness.

The JCT Staff helps policymakers by providing user-friendly 

distributional analysis in the form of our Distribution Tables. 

These convey how tax proposals would change the distribution of 

tax liabilities and tax burdens among taxpayers of different 

incomes, when compared with current law’s distribution patterns.

 Economists use “Gini coefficients” and other mathematical tools to 

describe the overall distributions of incomes (pre-tax or after-tax) in a 

society, but those tools are not intuitive and do not tell policymakers 

exactly how tax distributions would be affected by a revenue 

proposal.
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Committee on 

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Progressive and Proportional Taxes

Many policymakers are interested in whether a proposal 

would affect a tax’s progressivity. A progressive tax is 

one where average tax rates go up as incomes go up.

 Contrast this with a proportional tax. In a proportional tax, the 

average tax rate remains constant as income rises.

 If a tax imposes $3,000 in tax on $30,000 of income, $10,000 in tax 

on $100,000 of income, and $100,000 in tax on $1 million of income, 

the amount of tax paid increases with income, but the tax rate (10%) 

remains constant, and the tax is a proportional tax.

 And if at the same levels of income the taxes imposed are $3,000, 

$15,000 and $200,000, the tax is a progressive tax, because average 

tax rates increase with income.

One way to implement a progressive tax system is to 

increase marginal tax rates as incomes increase, but 

there are many other techniques.
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Committee on 

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What is the Right Distribution

of Taxes?

There is no straightforward answer to this question!

 In general, progressivity reflects our society’s goals for 

fairness.

 Ultimately this is the sort of question that the political system 

is uniquely well suited to resolve.

One partial justification for progressivity is the 

principle of the declining marginal utility of money.

 The idea is that one less dollar in his pocket should mean less 

to the rich taxpayer than to the poor one.

But at the same time, there are important economic 

efficiency costs to increasing marginal tax rates.

Difficult tradeoffs often must be made between equity 

(distributive) goals and economic efficiency concerns.
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The JCT Staff’s Distributional Work

The JCT Staff’s distributional analyses are designed to 

help policymakers make these difficult tradeoffs 

between equity and efficiency, not to suggest what 

degree of progressivity is appropriate. 

JCT Staff Distribution Tables model the incremental

changes in the distribution of tax costs and tax burdens 

that we expect to follow from a proposed change in 

law, when compared with current law.

 These Distribution Tables show the distributional effects of the 

proposal by income brackets, across a five-year window.

 These incremental distributional effects help policy makers 

determine whether a proposal is consistent with their fairness 

goals.

 Distribution Tables supplement revenue estimate tables.
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Taxation

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A JCT Staff Distributional Table

(Year One)

Present Law Proposal

Millions Percent Billions Percent Billions Percent Percent Percent

Less than $10,000 -$75 -1.0 $7 0.4 $7 0.4 8.7 8.6

10,000 to $20,000 -2,989 -11.5 26 1.5 23 1.4 7.5 6.7

20,000 to 30,000 -5,790 -9.4 62 3.5 56 3.3 13.4 12.2

30,000 to 40,000 -5,674 -6.4 89 5.1 83 4.9 16.1 15.1

40,000 to 50,000 -5,490 -5.4 102 5.9 97 5.7 17.4 16.4

50,000 to 75,000 -11,546 -4.5 256 14.6 244 14.4 19.1 18.3

75,000 to 100,000 -8,488 -3.5 244 13.9 235 13.9 21.7 21.0

100,000 to 200,000 -10,488 -2.6 408 23.3 397 23.5 24.2 23.6

200,000 and over -6,997 -1.3 555 31.7 548 32.4 27.8 27.4

Total, All Taxpayers -$57,536 -3.3 $1,748 100.0 $1,690 100.0 21.4 20.7

Source: Joint Committee on Taxation

Detail may not add to total due to rounding.

Note: Footnotes omitted.

DISTRIBUTIONAL EFFECTS OF THE CONFERENCE AGREEMENT FOR H.R. 1836[1]

Calendar Year 2001

Income Category(2)

Effective Tax Rate(4)

Change in Federal Taxes(3)

Federal Taxes(3)

Under

Federal Taxes(3)

Present Law Proposal

Under
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Committee on 

Taxation

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A JCT Staff Distributional Table

(Year Five)

Present Law Proposal

Millions Percent Billions Percent Billions Percent Percent Percent

Less than $10,000 -$76 -1.0 $8 0.4 $8 0.4 10.1 10.0

10,000 to $20,000 -3,867 -14.0 28 1.3 24 1.2 7.6 6.5

20,000 to 30,000 -7,937 -11.6 68 3.2 60 3.0 13.7 12.1

30,000 to 40,000 -7,720 -7.9 98 4.6 90 4.4 16.0 14.7

40,000 to 50,000 -6,945 -6.2 112 5.3 105 5.2 17.2 16.2

50,000 to 75,000 -16,630 -5.5 303 14.2 286 14.1 18.7 17.6

75,000 to 100,000 -14,709 -5.1 287 13.5 273 13.5 21.4 20.3

100,000 to 200,000 -24,654 -4.5 547 25.7 522 25.8 24.0 22.9

200,000 and over -21,182 -3.1 678 31.9 657 32.4 28.3 27.4

Total, All Taxpayers -$103,720 -4.9 $2,129 100.0 $2,025 100.0 21.6 20.6

Source: Joint Committee on Taxation

Detail may not add to total due to rounding.

Note: Footnotes omitted.

Federal Taxes(3)

Under

Proposal

Effective Tax Rate(4)

DISTRIBUTIONAL EFFECTS OF THE CONFERENCE AGREEMENT FOR H.R. 1836[1]

Calendar Year 2005

Income Category(2) Change in Federal Taxes(3)

Federal Taxes(3)

Under

Present Law
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Committee on 

Taxation

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Critical Issues in Constructing a 

Distributional Table

Definition of the relevant taxpaying unit.

 Whose income and tax liabilities will be measured? 

Measure of the tax unit’s income.

 Adjusted Gross Income? Haig-Simons income?

Determination of the incidence of the tax.

 Who really bears the tax? Statutory or economic incidence?

Measure of distributional effects.

 Distribute taxes paid? Or the economic burden of those taxes?

Changes in distributional effects over time. 

 Handled by 5 charts, one for each of next 5 years.
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Committee on 

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JCT Staff Distribution Tables: 

Whose Income?

JCT Staff tables measure the income of Filing Units.

 These are tax returns filed, less dependent returns and negative 

income returns, plus (imputed) nonfilers.

 Results are similar to households, but somewhat narrower. 

 Example: grandmother living with son and daughter in law, but 

filing her own return – one household, two filing units.

Other Government agencies use different measures.

 IRS SOI Division reports data by tax returns filed.

 Other agencies use standardized or actual households.

 Examples of the differences in results set out below.
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JCT Staff Distribution Tables: 

How Much Income?

JCT Staff tables are built around Expanded Income.

 Defined as Adjusted Gross Income + (1) tax-exempt interest, (2) 

employer contributions for health and life insurance, (3) employer 

share of FICA tax, (4) worker’s compensation, (5) nontaxable social 

security benefits, (6) insurance-equivalent value of Medicare benefits, 

(7) AMT preference items, and (8) section 911 income.

What income is missing from this list? Examples:

 Add-back for 401(k)/pension contributions/IRA contributions, plus 

income earned on retirement accounts.

 Unrealized capital gains.

 Imputed rental value of owner-occupied housing.

 Taxpayer’s share of corporate income (see below).
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Committee on 

Taxation

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JCT Staff Distribution Tables: 

Which Taxes?

JCT Staff tables distribute:

 The individual income tax (including refundable credits as 

negative taxes);

 Employment taxes (employer and employee shares); and

 Excise taxes

What taxes are missing?

 Corporate income tax.

 Estate and gift tax.

Why are they missing?

 These taxes are thought to be uncertain in their incidence. 

Individuals ultimately bear both (that is, a corporation is a legal 

fiction), but which individuals bear the tax is not certain.
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Committee on 

Taxation

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JCT Staff Distribution Tables: 

Tax Incidence

The question of tax incidence is a way of asking, who bears a tax? 

That is, how much tax should be assigned to each Filing Unit?

Largely for reasons of simplicity, available data, and certainty of 

outcome, JCT Staff individual tax distribution tables largely follow 

a tax’s statutory incidence – the tax is distributed to the individual 

with legal liability for the tax.

In 2 cases, JCT Staff tables follow the economic incidence of a tax.

 Economic incidence looks to who bears the ultimate economic 

consequences of a tax, not who writes the check to the IRS.

 Case 1: All excise taxes are distributed to consumers.

 Case 2: Employer’s share of FICA (employment) taxes are distributed 

to employees – that is, the taxes are treated as ultimately borne by 

employees (through lower wages).
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Committee on 

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JCT Staff Distribution Tables: 

Corporate Tax Incidence

Current JCT Staff practice is to ignore the economic incidence of 

the corporate tax (i.e., its ultimate cost to individuals) in our tables. 

 Individuals of course must ultimately bear the cost of the corporate 

income tax, but JCT Staff agnosticism reflects the uncertainty as to 

which individuals bear that cost.

 This issue is largely irrelevant for incremental changes to the 

individual income tax, but relevant to large-scale corporate reform.

CBO (and Treasury) assume that the corporate income tax is borne 

by all owners of capital (not just stockholders); that tax is then 

allocated to individuals in proportion to their capital income.

 CBO does not include investments in owner-occupied homes (and 

imputed rental value), or unrealized gains, in these measurements.

 CBO thus distributes actual tax revenues (like JCT), but on a broader 

range of taxes (following economic incidence for corporate tax).
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Committee on 

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JCT Staff Distribution Tables: 

Corporate Tax Incidence (cont’d)

Distributing the corporate income tax to owners of all 

capital is controversial.

 Some argue that employees bear much of the economic burden 

of the corporate tax, through reductions in wages. 

 Others argue that, over the revenue estimating window, the 

incidence falls mostly on owners of stock, not all capital.

 And still others argue that the answer differs across different 

industries (or different countries).

Similar issues exist for the estate tax.

 The question is, is the estate tax borne by the decedent, or by 

the heirs?

 Estate tax also raises the question (analogous to corporate tax) 

whether taxes on capital are borne by owners of capital, or 

labor, or both.
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Committee on 

Taxation

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JCT Distribution Tables: Distribute 

Tax Revenues or Tax Burdens?

JCT Staff Distribution Tables distribute the revenue consequences 

of a legislative proposal.

 This ties the distribution tables directly to our revenue tables.

But in some cases (e.g., capital gains) tax revenues present a 

misleading picture of changes in the burden imposed by the taxes 

collected.

 When capital gains rates go down, taxpayers rush to recognize 

accrued gains (termed “induced” gains).

 The result is a (temporary) increase in both the gains realized and 

taxes paid, but a lower tax burden (rate) on those realized gains.

JCT Staff tables reconcile these conflicting perspectives through 

their Effective Tax Rate columns:

 The total taxes distributed tie into the proposal’s revenue estimate.

 But the Effective Tax Rate (= average tax rate) columns signal the 

lower tax burden imposed when capital gains taxes are reduced.
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Committee on 

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Economic Incidence of Tax Revenues 

or Economic Burden of Taxation?

To summarize, JCT Staff today distributes the statutory incidence

of individual income tax revenues, and the economic incidence of 

employment and excise tax revenues. The Effective Tax Rate 

columns suggest a proposal’s effect on the real burden of taxes.

This dual picture technically is incomplete, because taxes impose 

on the private sector economic deadweight losses on top of the 

taxes collected (at whatever rate).

 The tax equivalent of the dog that didn’t bark!

 ETR columns do not address deadweight loss.

The 1993 JCT Staff “Redbook” (JCS-7-93) developed a method 

for distributing in table form the approximate economic burden 

imposed by taxes, not just the incidence of tax revenues.

 But this approach was soon abandoned, in part because policy 

makers found it difficult to understand.
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Constructing the Tables:

Changes in Taxes Paid

JCT Staff holds assignments of Filing Units to income classes 

constant, based on current law.

 Filing Units do not move up or down the income brackets to reflect 

any changes in Expanded Income resulting from the proposal.

 Brackets themselves are expressed in constant first-year dollars, so 

behind the scenes the income brackets creep up for Years 2-5.

JCT Staff methodologies employed in developing the numbers 

follow our revenue estimating methodologies.

 JCT Staff thus takes anticipated taxpayer behavior – dynamic effects 

– into account in calculating the distributional table numbers.

JCT Staff then distributes predicted incremental changes in tax 

revenues to Filing Units by income bracket.

 Distributions follow incidence assumptions described earlier.

 Does not address changes to economic burdens of tax (e.g., “induced” 

capital gains).
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Committee on 

Taxation

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Constructing the Tables:

Effective Tax Rate

Effective Tax Rate columns suggest how a proposal will change 

the relative tax burdens borne by taxpayers, by showing each 

income bracket’s taxes paid as a share of its Expanded Income.

JCT staff calculates the projected changes in Expanded Incomes 

for each income bracket (keeping assignment of Filing Units to 

original brackets unchanged) as a result of legislative proposal.

Projected Taxes Paid ÷ Projected Expanded Income

= New Effective (average) Tax Rate.

Since the numbers reflect anticipated behavior, a reduction in 

capital gains tax rate shows up (behind the scenes) as a change in 

projected Expanded Income as well as a change in projected taxes 

paid, so the Tables can show both lower tax burdens (a lower 

percentage of Expanded Income paid in tax), and more tax paid.
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Committee on 

Taxation

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Next Steps for JCT Staff Tables

Expand income classifications.

 Current tables stop at $200,000.

 New tables will add $200K - $500K, $500K - $1 million, and 

$1 million+.

Extend Distributional Analysis to 10 years.

 This will align distributional tables with revenue estimates.

 Tables for Years 1, 3, 5, 7, 10.

Expedited review of corporate and estate tax incidence.

 Goal is to determine whether a strong consensus can be found 

that one theory of economic incidence, even if itself not 

perfect, is demonstrably superior to current practice.
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Committee on 

Taxation

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Appendix I: Defining the Middle Class

Different methodologies lead to different answers. 

Examples of median pretax incomes from 2005:

 IRS: $30,881(by tax returns)

 Census: $49,202 (by households, cash income)

 CBO: $64,800 (by households, comprehensive income)

 JCT Staff: $33,857 (by filing units, expanded income) 

$85,074 (married family of 4)

How can these numbers be so different?

 Different measures of the relevant taxpaying unit (tax return, 

household, etc.).

 Different measures of the income (or wellbeing) of that unit.

 Different population data sets (e.g., only families of four).
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Defining the Middle Class (cont’d)

The IRS reports median adjusted gross income of 

taxpayers, as reported on tax returns.

 Result: 2005 median AGI of taxpayers (excluding dependent 

filers and those with negative income) = $30,881.

The Census Bureau reports money (cash) income of 

households.

 Includes wages, social security, unemployment 

compensation, public assistance, interest and dividends (but 

not capital gains), rental income, child support.

 Does not include noncash benefits, such as food stamps, 

health benefits, and subsidized housing.

 Result: 2005 median household money income = $49,202.
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Defining the Middle Class (cont’d)

CBO reports “comprehensive” income of households.

 CBO statistically matches Census Bureau household data to IRS tax 

data. This enables a more comprehensive measure of household 

income than Census data alone. (JCT Staff does similar statistical 

matches with slightly different data sets.)

 To rank households by quintiles, CBO adjusts incomes for 

household size by dividing household income by the square root of 

household size. Theory is that (i) a large household is less well off 

than a smaller household with the same income, but (ii) each new 

member is not as costly as the first. This process attempts to equate 

relative well-being of differently-sized households, solely for 

income ranking purposes. CBO main reports show unadjusted

incomes of households, but ranked using adjusted incomes.

 2005 mean of middle quintile (ranked as above) = $58,500. By 

contrast, 2005 median (ranked by unadjusted incomes) = $64,800.
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Defining the Middle Class (cont’d)

The JCT Staff distribution tables report the expanded

income of filing units. Median numbers not normally 

reported, but here are 2005 data from JCT tax model:

Medians refer to subsets of total population: so median 

family of four (expanded income, $85,074) refers to 

median of families of four, not median of all taxpayers!
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Committee on 

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Appendix II:

Progressivity and Redistribution

Observers often explain a preference for progressive income taxes as one 

element of a society’s commitment (expressed through the political 

process) to the redistribution of resources from high income taxpayers to 

lower income ones. 

But the redistributive effects of government policies ultimately are 

functions of government spending as well as government revenue 

collections.

Consider, for example, two otherwise identical countries that raise 

revenues through equally progressive new tax reforms:

 In Sylvania, the incremental revenues go to build new highway lanes reserved 

for cars costing more than $75,000.

 In Freedonia, the incremental revenues fund Medicaid outlays.

No government agency today regularly publishes data on the 

comprehensive redistributive effects of all government policies.