TREASURY METHODOLOGY FOR ESTIMATING 

TOTAL TAXABLE RESOURCES (TTR)

Revised November 2002 

The basis for Treasury’s methodology for estimating Total Taxable Resources (TTR) is the 

theoretical TTR framework developed by Sawicky (1986) and the experimental estimates 

developed by Carnevale (1986). Both of these papers were part of the Congressionally mandated 

Treasury study on the fiscal relations between the Federal, State, and local governments. Under 

Public Law 102-321, the Department of Treasury is required to provide annual estimates of TTR. 

The estimates are used in the formulas to allocate Federal funds among the states for the 

Community Mental Health Services and the Substance Abuse Prevention and Treatment block 

grants. 

An analysis of the Treasury methodology used from 1992 to 1997 to generate official estimates 

of TTR revealed inconsistencies with the original theoretical framework. As a result, a revised 

methodology was proposed by Compson and Navratil (1997) and reviewed by a panel of outside 

experts on fiscal capacity. There was a consensus among the reviewers that the revised 

methodology represents a substantial improvement over the original method. 

The following discussion presents the basic details of Treasury’s current methodology for 

generating official estimates of TTR which was adopted on September 30, 1998. Those 

interested in a more in-depth analysis of the methodology should see Compson and Navratil 

(1997) which is available on Economic Policy’s web page (www. treas.gov/offices/economicpolicy/index.html). A summary of the methodology used by Treasury from 1992 to 1997 to 

estimate TTR is also available on the web page. 

Summary of TTR 

As mentioned above, TTR is an outgrowth of the Congressionally mandated Treasury study on 

Federal, State, and local fiscal relations. Congress specifically requested that Treasury evaluate 

the various measures of the relative fiscal capacity of the states with particular concern about the 

ability of state personal income (SPI) to reflect accurately the relative ability of state and local 

governments to raise revenues to provide public services. It is widely recognized that SPI is an 

incomplete measure of a state's fiscal capacity because it does not include, and by definition is 

not intended to include, all of the potentially taxable income flows produced in a state. 

Examples of potentially taxable flows not accounted for in SPI include corporate profits retained 

for investment purposes. These retained profits are not part of personal income by definition, 

but may be subject to tax through corporate income taxes. In addition, business income received 

by out-of-state residents (dividends for example) are not reflected in SPI at the location of the 

business, but may be subject to taxation through state business taxes. Finally, commuter income 

- income earned in one state by residents of another state - may be subject to taxation in the state 

where it is earned but is not included in that state’s measure of personal income. 
Gross State Product (GSP), which has also been suggested as a measure of fiscal capacity, 

suffers from the same basic handicap as SPI in that it is not comprehensive. GSP by definition 

does not include income earned by residents from out-of-state sources. Specifically, resident 

earnings (wages, salaries, proprietor’s income, etc.) from out-of-state, and resident dividend and 

interest income earned from out-of-state sources are not included in GSP. 

The potentially large taxable income flows that are not accounted for in SPI and GSP (only a 

conceptual idea at the time of the Treasury study) implies that both measures, by themselves 

could significantly understate the relative fiscal capacity of the states. TTR was designed to 

overcome the lack of completeness associated with SPI and GSP by accounting for the crossborder income flows that are not accounted for in GSP. 

TTR is defined as the unduplicated sum of the income flows produced within a state (GSP) and 

the income flows received by its residents (SPI) which a state can potentially tax. The 

distinction between flows which a state can potentially tax and the actual fiscal choices made by 

states is critical. TTR says nothing about, nor does it consider, the actual fiscal choices made by 

the states. In sum, TTR is a flow concept, a comprehensive measure of all the income flows a 

state can potentially tax. 

Estimating TTR

TTR is currently generated using the following formula: 

TTRs = GSPs - (EMPLOYEEs + EMPLOYERs + FIBTs + FCESs)+ (DIVs + MINTs + 

 SITs + NCAPs + COMs) 

where for states: 

TTRs = total taxable resources 

GSPs = gross state product 

EMPLOYEEs = employee contributions to social insurance 

EMPLOYERs = employer contributions to social insurance (unpublished data) 

FIBTs = federal indirect business taxes (unpublished data) 

FCESs = federal civilian enterprises surplus/deficit (unpublished data) 

DIVs = dividend income

MINTs = monetary interest 

SITs = select social insurance transfers 

NCAPs = net realized capital gains (parts of this series are unpublished data) 

COMs = commuter income, residents from outside state borders (unpublished data) 

(see the discussion below about special treatment for the District of Columbia.) 

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The process of estimating TTR begins with in-state production, i.e. GSP, and subtracts 

components that are presumed not taxable by the states to derive modified GSP (MGSP). 

Various components of income that are derived from out-of-state sources are then added to 

MGSP to yield estimates for TTR. 

Subtractions from GSP to Derive MGSP

The following components of GSP were deemed not available to the states to tax and hence, 

were subtracted from GSP: 

(1) Federal Indirect Business Taxes: 

Federal indirect business taxes (such as excise taxes on gasoline, alcohol, tobacco, etc., ) and nontax 

liabilities (grazing fees, miscellaneous rents and royalties, etc) are not part of TTR on the grounds that they 

are sums paid to the Federal government, and thus are not taxable by the states. 

2) Employer and Employee contributions for Social Insurance: 

The employer and employee portions of Federal social insurance contributions are viewed in a manner 

analogous to Federal indirect business taxes--as payments to the Federal government not available to the 

states for taxation. Specifically, these transfers include: old age, survivors, and disability payments, 

railroad retirement and disability payments, Federal civilian employee retirement payments, military 

retirement payments, state and local government employee retirement payments, worker’s compensation 

payments (Federal and State), and other government disability insurance and retirement payments. It was 

not possible to separate out the contributions to state employee retirement plans. 

(3) Federal civilian enterprise surpluses: 

Although this is a relatively small item overall, it is larger in some states than in others. It consists of the 

surplus or deficit, net of subsidies, of federal government enterprises. These federal government enterprises 

include such large activities as the U.S. Postal Service, U.S. Department of Agriculture crop insurance 

programs, and several federal power authorities such as Bonneville and the Tennessee Valley Authority 

(TVA), as well as a number of smaller activities such as the operation of government canteens and the 

Government Printing Office (GPO). These federal government surpluses or deficits are removed from our 

measure of TTR because States cannot tax them. 

The removal of these components from GSP yields MGSP. 

Additions to MGSP to Derive TTR

MGSP does not account for all of the income flows that states could potentially tax. The 

following income flows are added to MGSP to derive TTR: 

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(1) dividends, and monetary interest income earned from sources outside the state 

Dividend income consists of dividends received by individuals and nonprofit institutions and the dividends 

that are received, retained, and reinvested by fiduciaries. Monetary interest income consists of: reportable 

interest income; interest income from municipal bonds; interest received by nonprofit institutions; and, 

interest income retained by fiduciaries. 

Ideally, only dividend and monetary interest income that was earned from sources outside of the state 

would be added to MGSP. However, the underlying data series from BEA does not distinguish this income

by source. Given this, dividend and monetary interest income are added to GSP on the presumption that 

most of this income comes from out-of-state sources and is thus not accounted for in GSP. This implies 

some double counting of income flows to the extent that the dividends and interest do, in fact, stem from

home state production. Compson and Navratil (1997) had originally intended to add rents and royalties 

under the same assumption. However, in generating their estimates for rents and royalties, BEA assumes 

that all rents and royalties are intrastate. As a result, the GSP and SPI estimates are identical and adding 

them to MGSP would be pure double counting. 

 (2) select transfers from the Federal government1 

These are transfers from select social insurance programs. Contributions to these programs are subtracted 

from GSP. Specifically, these transfers are: old age, survivors, and disability payments, railroad retirement 

and disability payments, worker’s compensation payments (Federal and State), and other government 

disability insurance payments. 

(3) Net realized capital gains 

The net realized capital gains are added because they are not accounted for in GSP and they have an impact 

on the ability of a state’s residents to pay taxes. The estimates come from Internal Revenue Service, 

Statistics of Income Bulletins. 

(4) the earnings of state residents who work outside the state borders 

Resident earnings from out-of-state employment (annual gross inflows) are added to MGSP on the grounds 

that these earnings are not accounted for in the resident’s “home” state estimates of GSP. The BEA 

estimates for resident earnings from out-of-state employment include wage and salary income plus other 

labor income, less personal social insurance contributions. BEA estimates state level gross inflows and 

gross outflows to generate a net residence adjustment (gross inflows less gross outflows). 

 

The complex tax circumstances in the District of Columbia require special adjustments in the 

TTR method. Since the District is proscribed by Federal law from taxing the earnings of 

commuters from outside its borders, we have also subtracted the earnings of non-residents. The 

 

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1

 When TTR was revised in 1998, the estimates for these transfers also included Federal civilian employee 

retirement benefits, military retirement payments, state and local government employee retirement payments, and 

other government retirement payments. Since the definitional changes to the NIPA’s in 1999, these payments are no 

longer included in the transfer payments or in SPI since they are not considered part of current production. Another 

definitional change made in 1999, the treatment of government consumption of fixed capital (including software), 

may also have an impact on the estimates of TTR. The Treasury is currently consulting with staff from the Bureau 

of Economic Analysis to investigate the impact of these definitional changes on the estimates of TTR. 
adjustment for the District of Columbia is equal to the net residence adjustment and results in a 

substantial reduction in the MGSP of the District of Columbia. 

Data

With the exception of the net realized capital gains estimates, all of the data used to generate the 

estimates for TTR are provided by the Bureau of Economic Analysis (BEA). While much of the 

GSP and SPI data used to estimate TTR are publicly available, the following components are not 

published and thus, cannot be released: Federal indirect business taxes, Federal enterprises 

surplus/deficit, employer contributions to social insurance, monetary interest income, and the 

gross inflows and outflows. The net realized capital gains estimates are from the Internal 

Revenue Service, Statistics of Income Bulletins. 

TTR estimates for a given year will only be made when both GSP and SPI data are available for 

that year. This contrasts with the original paradigm for estimating TTR which produced 

estimates for the latest year for which SPI data is available, even though GSP data for that year is 

not available. The primary reason for this change is that the new method uses GSP as a base, 

and adds to and subtracts from that base various components. Mixing different years of data for 

the various components would not be appropriate. As a result of using the same year data, the 

years estimated in September 1998 (for years 1994-1996) and September of 1997 (estimates 

were for 1994-1996) are the same. 

Since Treasury began generating official estimates of TTR for use in the SAMHSA block grant 

programs in 1992, its standard policy regarding the underlying data to generate the estimates has 

been to use the latest estimates of GSP and SPI produced by BEA. The most recent estimates 

produced by BEA reflect the current state of knowledge regarding the measurement of income

and production at the state level. This notwithstanding, it should be acknowledged that there are 

typically differences in the underlying data used to generate the most recent estimates of GSP 

and SPI. 

The TTR estimates released on September 30, 2002 contained estimates for 1998 – 2000 and 

were generated using the GSP and SPI estimates released in 2002. GSP estimates released in 

June of 2002 contain new estimates for 2000 and revised estimates for 1998 and 1999. The 

estimates are consistent with the estimates of GDP by industry that were published in the 

November 2001 Survey of Current Business. The SPI estimates released in September 2002 

contain revised estimates for 1999 through 2001. The revised estimates incorporate the annual 

revisions of the NIPAs that were released in August 2002 and more complete and detailed state 

source data than was previously available. 

As a result, the SPI estimates for 1999 and 2000 are based on more recent NIPA estimates and 

state source data than the GSP estimates. Unfortunately, nothing can be done regarding the 

inconsistencies in the underlying data/information used to generate the GSP and SPI data series 

except to acknowledge them and make users of the TTR estimates aware of the limitations in the 

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data. BEA has indicated that for non-benchmark estimation cycles, the revisions to the state 

level estimates for GSP and SPI for the previous two years are typically small. 

Sources:

Carnevale, John, Experimental Estimates of Total Taxable Resources, 1981-84, in the FederalState-Local Fiscal Relations: Technical Papers, Vol. 2, Office of State and Local Finance, 

Department of Treasury, September 1986. 

Compson, Michael, and John Navratil, An Improved Method for Estimating The Total Taxable 

Resources of the States, Treasury Research Paper No. 9702, Office of the Assistant Secretary for 

Economic Policy, Department of Treasury, 1997. 

Sawicky, Max, The Total Taxable Resources Definition of State Revenue-Raising Ability, in the 

Federal-State-Local Fiscal Relations: Technical Papers, Vol. 2, Office of State and Local 

Finance, Department of Treasury, September 1986. 

Office Of Economic Policy 

U.S. Department of Treasury 

Originally released on October 1, 1998 

Revised December 2002