Options for Changing the Tax Treatment of Charitable Giving
"...For this analysis, the Congressional Budget Office (CBO)examined how much taxpayers in various income groups donate to charities and what types of organizations receive those donations. CBO also investigated how changing the structure of tax incentives for giving would affect the tax subsidy (the cost in forgone revenues to the federal government), the overall level of charitable
giving, and the extent to which different income groups benefit from the tax preference. Specifically, CBO looked at 11 options for altering the current income tax treatment of charitable giving, which can be grouped into
4 categories:

 Retaining the current deduction for itemizers but adding a floor.
 Allowing all taxpayers to claim the deduction, with or without a floor.
 Replacing the deduction with a nonrefundable credit for all taxpayers, equal to 25 percent of a taxpayer’s charitable donations, with or without a floor.
 Replacing the deduction with a nonrefundable credit for all taxpayers, equal to 15 percent of a taxpayer’s charitable donations, with or without a floor..."