Nearly all traditional charitable-giving studies conclude donors are more responsive to price-reducing charitable deductions (the price effect) than they are to income-reducing tax payments (the income effect). Thus, taxes stimulate giving. In addition, this empirical evidence also indicates that the charitable deduction is treasury efficient. This traditional understanding was recently challenged by studies employing observations on the same individuals across time (panel data). These panel studies provide evidence which suggest that donors are either much more responsive to income reducing tax payments than they are to price-reducing charitable deductions or just as responsive to both. Further, price elasticity estimates are much greater than negative one. Thus, the deduction is inefficient and giving is either neutral to, or inhibited by, taxes. / Ph. D.