稅制調整與地下經濟－－臺灣動態隨機一般均衡模型分析

TAX REFORM AND THE UNDERGROUND ECONOMY IN TAIWAN: A DSGE APPROACH

臺灣自2000年以來，政府稅收和其它收入占GDP的比大致呈現一下滑的趨勢，造成政府舉債的逐年增加。因此，如何增加稅收以健全財政為目前臺灣經濟所面臨的重要課題。本文建構一個包含地下財及合法財之兩部門動態隨機一般均衡（dynamic stochastic general equilibrium）模型，透過校準，分析兩種稅率的調整—提高查緝罰款率或提高消費稅率—對於稅收以及總體經濟的影響。結果顯示，兩種方法皆可以達到增加稅收的目的，但對兩部門的總體影響大不相同。以增加同樣的政府總稅收占總產出之比例而言，提升查緝罰款率對總產出負面效果較小，且能縮小地下財部門並擴大正常財部門的產出。提升消費稅率對於兩部門產出的效果則恰好相反。文中也發現兩部門間的勞動替代彈性對增稅之總產出效果有重要影響。當兩部門勞動替代彈性變大時，可減緩總產出面臨的負面衝擊。本文的另一貢獻是，提供一個結構總體模型，用以推估一經濟體之地下經濟的規模。 The tax revenue-to-GDP ratio in Taiwan has gradually declined since 2000. Among various approaches to raising revenues, this paper compares increasing the tax evasion penalty rate on underground economic activity to increasing the consumption tax rate, using a two-sector DSGE model. It finds that both approaches can raise revenues but have very different sectoral effects: raising the tax evasion penalty shrinks the underground economy and increases the output of the formal sector, opposite to the effects of raising consumption taxes. Increasing the consumption tax rate has more negative effects on output than increasing the tax evasion penalty for a given revenue-to-output share raised on impact. The paper also finds that higher sectoral elasticity between labor of the two sectors produces less negative effects on total output. Finally, the calibration exercise, making use of tax revenue-to-output data, offers a structural method to assess the size of an underground economy.