資本技術互補經濟體系下的租稅政策

Tax Program With Capital-Skill Complementarity

俞欣榮(Hsin-Jung Yu)

指導教授 ： 楊建成

共同指導教授 ： 蔡宜展(Yi-Chan Tsai)

國立臺灣大學/社會科學院/經濟學研究所/博士(2015年)

https://doi.org/10.6342/NTU.2015.01495

摘要

美國的經濟體系自二戰後，資本設備的存量與技術在過去五十年來經歷了快速而顯著的提升。於此同時，由於美國的生產科技具備資本與技術勞工的互補性質，設備的技術進步也同時改變了勞動市場的薪資結構，造成技術勞工與非技術勞工的差距增加，影響了經濟體系的所得分配與社會福利。本篇研究即是討論政府在無法辨別技術與非技術勞動者的前提下，如何設計最適的租稅結構，在極小化賦稅所產生的扭曲前提下，極大化社會的福利。本篇論文首先使用過去的估計方法, 以Gordon (1992) 的結果為基礎，更新並估計資本設備的技術創新；另一方面，我們也使用Current Population Survey 的資料，更新美國技術與非技術勞工的相對平均工資比率。透過Ecstein and Nagypal (2004) 的樣本篩選原則，我們發現技術溢酬(skill premium)自1970年以來不斷呈現上漲的趨勢，並在2008年達到歷史的新高。
在給定上述的估計基礎下，我們使用Mirrlees tax 的租稅設計，計算自1947至2000的動態最適稅率。藉由上述估計出來的結果，我們發現在資本技術互補的經濟體系中，最適的邊際資本設備的稅率與非技術勞動所得的邊際稅率為正，而邊際的技術勞動的稅率為負。其背後的經濟直覺，目的是為了要降低美國經濟體系下的技術溢酬(skill premium)。由於過高的技術溢酬與資本累積將造成嚴重的技術溢酬的差異惡化，進一步影響市場中資訊不對稱的現象，因此對資本設備與非技術勞動者課稅，但對技術勞動者補貼將能有效給予市場的參與者誘因揭露自己的資訊。另一方面，隨著資本設備的生產效率不斷提升，政府必須要在生產效率與訊息接露的互動中進行取捨。我們發現針對資本課稅的負擔比例將隨著技術的創新而遞減；反之，技術勞動者的補貼將減少，但非技術勞動者的課稅將逐漸提高，意味著政府在逐漸提高的技術進步中，逐漸以邊際勞動稅率取代邊際資本稅率。而另一方面，為了降低技術與非技術的稅後所得差異，技術勞動者所面對的定額稅將隨著技術創新而提高，反之非技術勞動者所受到的移轉也會逐漸上升，造成技術勞動者的平均稅率呈現上升的趨勢，而非技術勞動者的平均稅率呈現遞減的現象。我們最後也利用電腦的模擬比較Mirrlees 的租稅政策與現存美國的租稅政策。我們發現：如果政府使用Ｍirrlees tax來進行所得重分配，則能夠較現存的租稅制度有較高的生產水準與消費水準，同時技術溢酬與消費不均的比例也會顯著下降。

關鍵字

資本技術互補 ； 工資不均 ； 技術進步 ； 資訊不對稱 ； 最適租稅

並列摘要

The post-war period has witnessed a secular decline in the relative price of capital equipment and an increase in the equipment to GDP ratio. With capital-skill complementarity, more capital equipment will raise the demand for skilled worker and thus the skill premium, which increases the disparities of economic well-being between skilled and unskilled workers. How should a government set taxes on capital versus labor dynamically in face of the rising inequality across workers? Employing an empirically plausible capital-skill complementarity form of production functions as suggested by Krusell et al. (2000), this paper attempts to answer the question by means of the Mirrlees approach. In particular, the government cannot distinguish between skilled and unskilled workers due to information frictions and needs to design a tax program such that workers will truthfully reveal their types. Under the utilitarian and separable utility function, if the skill premium is larger than one, then only the skilled workers have the incentive to mimic the unskilled workers. A higher skill premium allows the skilled workers to have more leisure time when pretending to be unskilled workers and makes the incentive problem more difficult to deal with. Therefore, the government imposes respectively positive, negative and positive tax rates for capital equipment, skilled and unskilled workers to reduce the wage premium and help resolve the incentive problem. Following the secular decline in the relative price of capital equipment, the efficiency loss from taxing capital equipment rises, and the equilibrium tax rates for capital equipment fall while the equilibrium tax rates for both types of workers rise. Over the whole transitional dynamics, the tax rates for capital equipment, skilled and unskilled workers however remain positive, negative and positive, which indicates the concern for incentive problem dominates the concern for efficiency losses. Finally, relative to the current U.S. fiscal policy, the output level will be higher and the consumption inequality will be lower under our Mirrleesian tax program.

並列關鍵字

Capital-Skill complementarity ； wage inequality ； technological change ； incomplete information ； optimal taxation

參考文獻

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