研發競爭與政府政策的三個議題

Abstract

內生技術變革的一個重要方面是既有廠商和新廠商之間的研發競爭。在這篇論文中，我們建立了一個以在位者的自我產品改進和進入者的創造性破壞為特色的熊彼特成長模型，以尋求對這一問題的一些解釋。我們強調研發競爭在决定政府政策效果方面的關鍵作用。第二章探討了貨幣政策對創新、經濟成長和社會福利的影響。本章的關鍵發現是，提高名目利率會促進既有廠商的自我產品改進，但不利於新廠商的創造性破壞。因此，貨幣政策對成長的總體效果是不確定的，取決於貨幣政策如何影響既有廠商和新廠商之間的研發競爭。第三章探討了多種補貼的效果。我們發現，對中間財的生產或對既有廠商的自我產品改進的補貼可以有效地促進經濟成長，但補貼新廠商的研發能否促進成長則是不確定的。此外，我們發現，就促進成長和提高福利而言，生產補貼似乎比研發補貼更有效。在第四章，我們將異質性家計單位引入模型，並探討專利保護對成長和不平等的影響。具體來說，我們發現提高專利的廣度並不影響既有廠商的產品改進，但會促進新廠商的創造性破壞，從而對經濟成長產生正面效果。然而，加强阻礙式專利會促進既有廠商的產品改進，但不利於新廠商的創造性破壞，因而可能對經濟增長產生倒U型的效果。關於專利保護對不平等的影響，我們發現，雖然提高專利廣度會導致收入不平等和消費不平等的提高，但加强阻礙式專利只會提高消費不平等，對收入不平等的影響則是不確定的。

An important aspect of the endogenous technological change is the R&D competition between incumbents and entrants. In this dissertation, we develop a Schumpeterian growth model with the own-product improvements of incumbents and the creative destruction of entrants in seeking to shed some light on this issue. We highlight the crucial role of R&D competition in determining the effects of government policies. Chapter two explores the effects of monetary policy on innovation, economic growth, and social welfare. The key finding of this chapter is that increasing the nominal interest rate stimulates the incumbents’ own-product improvements but deters the entrants’ creative destruction. Therefore, the overall effect of monetary policy on growth is ambiguous, depending on how monetary policy affects the R&D competition between incumbents and entrants. Chapter three revisits the implications of various subsidies. We find that the subsidy on intermediate goods production or the incumbents’ own-product improvements is effective in promoting economic growth, but whether the subsidy on the entrants’ R&D investment can promote growth is ambiguous. Furthermore, we find that in terms of promoting growth and raising welfare, the production subsidy seems more effective than the R&D subsidies. In chapter four, we introduce heterogeneous households into the model and explore the effects of patent protection on growth and inequality. Specifically, we find that increasing patent breadth does not affect the incumbents’ own-product improvements but stimulates the entrants’ creative destruction, thereby generating a positive effect on economic growth. However, strengthening blocking patents stimulates the incumbents’ own-product improvements but deters the entrants’ creative destruction, and thus may have an inverted-U effect on economic growth. As for the implications of patent protection on inequality, we find that while a higher level of patent breadth leads to an increase in both income inequality and consumption inequality, a higher level of blocking patents generates an ambiguous effect on income inequality and a positive effect on consumption inequality.