稅基侵蝕模型之探討－－以Browning模型與A-S模型之比較為例

The Economic Analyses of Tax Evasion Based on the Browning and A-S Models

逃稅最顯著、最直接的後果是國家稅收收入的減少與各級政府應上繳國庫收入的流失，政府為了抑制蔓延的逃稅行為，需要不斷加強徵管查緝，這又會使徵稅成本不斷提高。事實上，稅收乃稅率與稅基相乘而得，任何一種稅目收入多寡均取決於稅率與稅基，直覺上似可推論只要提高稅率或擴大稅基，稅收將隨之增加，惟拉佛曲線（Laffer curve） 證明當政府提高稅率到達一定水準之後，可能造成逃稅增加與稅基流失，導致稅收不增反減；最後導致一國稅收改變。以所得稅為例，其計稅依據是實際所得與規定的稅率計算徵收，當政府以「所逃之稅」為逃漏稅之處罰基礎，由納稅人觀點，稅基侵蝕金額變動導致納稅人預期效用之變動為何，倘政府改以「所逃之所得」為逃稅之處罰基礎，兩種課稅模式在租稅理論上對實徵稅額、稅基侵蝕、納稅人租稅遵循行為之影響為何，為本文主要研究重點。

The most significant and most immediate consequence of the tax evasion is the reduction of the state's tax revenue and the loss of state treasury revenueto all levelsof government. In order to curb the spread of tax evasion, the government needs to continue to strengthen the collection and inspection, which in turn will increase the cost of taxation. The Laffer curve proves that when the government increases the tax rate to a certain level, it may result in an increase in tax evasion and a loss of tax base, resulting in an increase in tax revenue.In the case of income tax, for example, the taxable basis is calculated on the basis of the actual income and the prescribed tax rate. When the government chooses the 'tax evaded' or 'incomeevaded'as the basis of the tax evasion. What is the change in the amount of taxpayer's change in the expected effect of the taxpayer.this paper adopts from the Browning (1989)and A-S(1972) setting by introducing factors which have important consequences for taxpayers’ tax evasion behaviors and revenue-maximizing tax rate .