One of the concerns expressed about the flat tax is that it would eliminate the deduction for charitable contributions at the same time that it imposed a single, lower income tax rate.

However, there is evidence that increasing personal income, which is a goal of the flat tax, would have a greater positive effect on giving than the charitable deduction.

• Total charitable giving surged to well over $100 billion for the first time in 1988, even though previous tax reform legislation had decreased the value of the charitable deduction from 70 percent to 28 percent.

• Historically, when the value of the charitable deduction rises, giving falls, and when the deduction's value falls, giving rises.

• That's because lawmakers make up for the income lost to deductions by increasing tax rates for all taxpayers, which lowers personal income.

• The deduction benefits highest income earners the most, although the greatest percentage of income given to charity is by lower-income groups.

• Thus, in 1992, in effect all taxpayers paid for the 26.1 percent of tax filers who claimed $63.8 billion in deductions for charitable contributions.

However, surveys indicate that tax considerations are not a significant motivation for charitable giving.

Source: Rebecca S. Schaefer, "So, What Gives? How Tax Policies Affect Charitable Donations," December 20, 1995, Issue Analysis No. 19, Citizens for a Sound Economy Foundation, 1250 H Street, NW, Suite 700, Washington, DC 20005, (202) 783-3870.