The Optimal Size of Public Spending and the Distortionary Cost of Taxation

Feldstein (1997) reviews his and others' contributions in the distortionary costs of taxation, arriving at a remarkable estimate that the cost per incremental dollar of government spending is a very high $2.65. Kaplow (1996) argues that it is optimal to supply a public good whenever the benefit/cost ratio exceeds one, contrary to the orthodox position since Pigou (1928) that the benefits of public goods must exceed their direct costs by an amount sufficient to outweigh the distortionary costs of taxation. This paper largely reconciles these two apparently opposing positions. The large distortionary costs exist on the revenue side but is largely offset by the negative distortionary costs or distributional gain on the spending side. However, both Kaplow's and Feldstein's arguments have to be subject to important qualifications. Additional arguments relevant to the central public finance question "How big should the public spending be?" are also reviewed. The prevalence of environmental disruption effects, the existence of burden-free taxes on diamond goods, and the importance of relative-income effects all favor the lowering of the required benefit/cost ratio for public goods and, as a rule, more public spending. The reason for the difference between the existence of distortion (in comparison to a lumpsum tax) as emphasized by Browning and Liu (1998) and the unitary marginal cost of public fund is also explained graphically.