In light of this increasingly probable prospect, CDA analysts simulated the 10 percent tax cut plan in a highly sluggish economy, in which the United States enters much lower growth in 1999 and remains in a slowly growing economy throughout 2000. How much better would U.S. economic performance be in such a slow-growth economy if Congress enacted the 10 percent tax cut plan?
Charts 4, 5, and 6 show the effects of a 10 percent tax rate reduction on three key economic indicators: the level of gross domestic product, inflation-adjusted disposable personal income, and the level of personal savings. The bars in these graphs show how much the slow-growth economy differs from the "normal" growth economy, or the WEFA baseline of continued, steady economic expansion. For example, Chart 4 shows that the slow-growth economy produces $34 billion less domestic product than the WEFA baseline in 1999. By 2002, this slow-growth economy is $142 billion smaller than the baseline. However, changing tax policy today by cutting marginal tax rates by 10 percent restores over $35 billion in output to this slow economy.


The results are more dramatic for inflation-adjusted disposable personal income and the level of personal savings. Although the tax policy change makes little difference to the level of disposable income in 1999, it significantly mutes or reverses the slow-growth forecasts in the remainder of the six-year period. In fact, the tax cut makes a $100 billion difference in 2004, or $916 for the average household, when the slow-growth decrease of $71 billion becomes an increase above baseline of $29 billion.
For personal savings, each year of the forecast shows higher levels than those in the slow-growth economy without tax cuts (see Chart 6). For the first three years, 1999 through 2001, the decline in savings without tax cuts becomes an increase above baseline. This result, when combined with the other economic indicators, clearly points to an unexpected benefit of this tax policy proposal: If the economy declines, as some economists expect, the level of decline will be less and the keys to recovery--savings and consumption--will be strengthened.


A few forecasters believe that the rapid economic growth of the past three years will continue into the next several years. That is, they hold that the current economic expansion will weather the turmoil in Asia and Latin America, and that the U.S. economy will grow at even faster rates than the baseline for the next three or four years. This "fast-growth" scenario raises a set of economic policy considerations that are different from those raised by the slow-growth scenario. For example, will the Federal Reserve raise interest rates to slow the economy, and will businesses be able to borrow funds to fuel their growth given the great need of foreign governments for new sovereign debt?
The fast-growth variant of the WEFA baseline sheds some light on the capacity of the U.S. economy to absorb the tax cut if growth is faster than expectations over the next few years. Charts 7-9 show the change in gross domestic product, inflation-adjusted disposable personal income, and personal savings in the fast-growth variant of the WEFA baseline model. Like the slow-growth results, the modeling exercise indicates that reducing marginal tax rates by 10 percent supports stronger economic performance across the forecast period.
NOTE ON INCOME TAX AND CAPITAL GAINS TAX REDUCTIONS IN A FULL-EMPLOYMENT ECONOMY
There is a slight reduction in capital taxation contained in the 10 percent marginal rate cut plan. Although the proposal reduces tax rates on labor income, it specifically excludes long-term capital gains from the 10 percent rate cuts. This exclusion means that the tax premium on capital changes very little, which results in small changes in investment over the ten-year forecast period.
From the standpoint of policy changes that support stronger economic growth, this exclusion is an important deficiency in the 10 percent tax cut plan. Tax policy changes that principally affect labor income may do little to stimulate investment in new and expanded plant and equipment. The added economic growth from the tax policy change that appears in the WEFA model simulation stems primarily from additional consumption. A cut in capital taxes, such as a cut in the capital gains tax rate, would have added more growth to the simulated economy by stimulating private investment.
Such a cut in capital taxes can be especially important in a rapidly growing economy. With the current annualized growth rate of the U.S. economy above 3 percent and unemployment at near-record post-World War II lows, many economists recommend that businesses seek to add capital rather than expensive labor that is in short supply. However, the failure to reduce the tax premiums on capital in a fashion proportional to that on labor means that less of this substitution takes place, which shows up in our economic model as only a modest increase in private investment from FY 2000 to FY 2009. Put another way, in the view of many economists, the key to growth in an economy with very low unemployment and productive capacity at high levels is to expand productive capacity by stimulating investment through reductions in taxes on capital.
CONCLUSION
Reducing marginal income tax rates for individual taxpayers would produce numerous fiscal and economic benefits. Not only would taxpayers see their tax liabilities drop by $797 billion between fiscal years 2000 and 2009, but the stronger economy would expand the tax base and return $164 billion in new tax revenues. Average tax liabilities in 1999 would decline by $700, with tax savings flowing to taxpayers in every filing category and family type.
The economic benefits are equally widespread. Over the forecast period, gross domestic product would expand by an average of $35.9 billion after inflation, civilian employment would grow throughout the ten-year period by an average 289,000 above baseline, and personal disposable income after inflation would increase by $106.3 billion by the end of FY 2009. Given the currently strong economy but low savings rate, the healthy expansion of personal savings is a particularly important result: Enacting a 10 percent rate cut would support an average $40.6 billion increase in personal savings between FY 2000 and FY 2009.
Moreover, the implementation of this tax policy change appears to support stronger economic growth in either a slow-growth or fast-growth economy. While some analysts argue that tax rate reductions are unaffordable in a sluggish economy or overheat an economy growing at annual rates well above current baseline forecasts, the modeling results do not support this view. The 10 percent rate reduction significantly improves economic performance in the slow-growth variant of the baseline model. In the fast-growth variant, the 10 percent tax rate reduction appears to be fully absorbed by the economy and to support additional growth.
William W. Beach is John M. Olin Senior Fellow in Economics and Director of the Center for Data Analysis at The Heritage Foundation. D. Mark Wilson is former Labor Economist in the Center for Data Analysis. Ralph A. Rector, Ph.D. is Project Manager for the Center for Data Analysis. Rea S. Hederman is Research Analyst in the Center for Data Analysis. Aaron B. Schavey is a former Economic Policy Analyst in the Center for Data Analysis.
Appendix A: Methodology
Heritage economists follow a two-step procedure in analyzing the revenue and economic effects of proposed tax policy changes.
First, analysts estimate the taxpaying population eligible for the tax change, the base of taxable income absent any change in the economy, and the appropriate tax rates and credits. Revenue estimates based on these calculations are frequently called "static" estimates, largely because they are unaffected by changes in the behavior of taxpayers that stem from tax policy reforms.
Second, these static revenue changes are introduced into the WEFA U.S. Macroeconomic Model. The WEFA model has been designed in part to estimate how the general economy is reshaped by policy reforms, such as tax law changes. CDA and WEFA economists have developed a model for The Heritage Foundation to embody the economic and budgetary assumptions published by the Congressional Budget Office in January 1999. This specifically adapted model produces dynamic responses from the CBO baseline as a result of proposed policy changes.
The following sections describe how Heritage economists developed the static estimates described in the report, how these static results and other assumptions were used to develop the case studies described in the report, and how the static estimates were introduced into the WEFA model to estimate the dynamic economic and budgetary results.
STATIC REVENUE ESTIMATE
Static revenue changes are computed using the IRS 1994 Public Use File produced by the Statistics of Income Division (SOI). This file is the latest available public use micro-database released by the IRS and is a sample of tax returns filed in 1994.
Heritage Foundation analysts used a tax simulation model to estimate tax liability under current law and the proposed changes contained in the Tax Cuts for All Americans Act (S. 3) and the 10 Percent Tax Cut Act (H.R. 3) that have been introduced in the 106th Congress. The Heritage model also accounts for major changes introduced into tax law by the Tax Reform Act of 1997, such as the Child Tax Credit. The only change made in the model was to reduce marginal tax rates by 10 percent for each tax bracket. Tax changes were computed for each record in the IRS 1994 SOI Public Use File.
Heritage analysts adjusted the static revenue estimates to reflect the fact that a portion of the taxes on capital gains income would not be affected by the reduction in regular tax rates because of the special treatment of capital gains income. This adjustment was based on the amount of income that was subject to the lower capital gains rate in 1994 and projected to 2009 using data from the Congressional Budget Office's January 1999 economic and budget outlook.
Heritage analysts also estimated the amount that proposed tax reductions would be offset by increases in Alternative Minimum Tax revenues. As economic growth and inflation require more and more taxpayers to begin paying the AMT, the number of taxpayers eligible for the proposed tax cut declines and the amount of income subject to the AMT increases. The increase in the number of AMT taxpayers was projected to 2009 using data from a Joint Committee on Taxation (JCT) report on the Individual Alternative Minimum Tax. Heritage analysts applied the estimated number of AMT taxpayers to an estimate of the mean regular tax paid by AMT taxpayers that was developed using data from the JCT AMT report and the IRS 1994 SOI Public Use File. The estimated increase in AMT tax revenue was then used to partially offset the static decline in income tax revenue resulting from the proposed tax rate reductions.
The first two years of the static revenue estimate were further adjusted to reflect the difference between the effective date of the tax cut and the actual timing of changes in the withholding tables, estimated tax payments, and amount of tax refunds received in 2000. Although the effective date of both H.R. 3 and S. 3 is January 1, 1999, Heritage analysts assumed that the Treasury Department will not change the withholding tables until January 1, 2000. Therefore, just 25 percent of the $72.7 billion, or $18.2 billion, is returned to taxpayers in the final two quarters of 1999. The remaining 75 percent of the 1999 static tax cut estimate, or $54.5 billion, is returned to taxpayers in the first two quarters of 2000 in the form of higher tax refunds.
CASE STUDIES
The case studies were taken from the March 1998 Current Population Survey conducted by the Bureau of the Census. The reported income for each case was adjusted to the years 2000 and 2005 using earnings and other income forecasts provided by the WEFA U.S. Macroeconomic Model. In one instance, the family in the 36 percent tax bracket was assumed to use itemized deductions instead of the standard deduction. They were given the average amount of itemizations for their income level, as reported in the SOI database.
The tax for the case studies was determined by subtracting the amount of exemptions and deductions from total income and then taxing that amount by the appropriate bracket. Federal tax computations for the examples use values that have been adjusted for increases in inflation. These case studies are snapshots in time and do not reflect changes that might occur over the period in marital status, family size, or employment status.
DYNAMIC ECONOMIC AND BUDGETARY ESTIMATES
The WEFA model contains a number of variables that are used to simulate proposed policy changes. The following changes were made in the model.
Average Effective Tax Rate
The WEFA model contains a variable that measures the total amount of all federal taxes on individual income as a percentage of the nominal personal income tax base. Heritage adjusted this average effective tax rate downward for each of the forecast years to reflect our static revenue decrease estimates.
Labor Force Participation and Average Weekly Hours
Small adjustments were made in the model's exogenous labor force participation rate and the number of hours worked to account for the dynamic effects of decreasing marginal income tax rates. These adjustments are based on previous research by Heritage economists and the Congressional Budget Office study Labor Supply and Taxes, dated January 1996. This change increases the labor force participation rate by 0.1 percentage points per year from 2000 to 2009, and average weekly hours by 0.2 hours per week.
Corporate AAA Bond Rates and 30-Year Treasury Bond Rates
Heritage economists decreased the corporate AAA bond rate by 3 basis points to reflect the lower tax rates on interest and dividend income reported on personal income tax forms. In 1994, 5.1 percent of adjusted gross income was interest and dividend income. Heritage economists also decreased the 30-year Treasury bond rate to maintain the historic interest rate spread between the two rates. The corporate AAA bond rate is a component in the WEFA model equation that calculates the cost of capital. This change decreases the corporate bond rate and 30-year Treasury bond rate by 2 basis points from 2000 to 2009.
Business Sector Price Index
Heritage economists decreased the business sector price index to reflect the lower tax rates on business income reported on personal income tax forms. In 1994, 7.4 percent of adjusted gross income was business, partnership, and subchapter S corporate income. Heritage economists assume that lower tax rates on this income will lower the rate of increase in the business sector price index. This change decreases inflation by 0.1 percentage points per year.
Monetary Policy
The model assumes that the Federal Reserve Board will react to this policy change as it has historically. This assumption was embodied in the Heritage model simulation by including the stochastic equation in the WEFA model for monetary reserves. This assumption increases both short-term and long-term interest rates by 20 basis points from 2006 to 2009, but has little effect on interest rates from 2000 to 2005.
Appendix B:
How Cutting Tax Rates by 10%
Would Affect Selected Economic Indicators

