حفاظت از حقوق مالکیت معنوی و رشد درونزا: آیا قوی تر همواره برتر است؟

This paper uses a variety expansion model of endogenous growth to examine the effect of intellectual property rights (IPR) protection on economic growth in a closed economy. Most of the studies in the literature show that, in closed economies, enhancing the protection of IPR increases the expected duration of monopoly and the associated incentive to innovate. A large incentive to innovate enhances the growth rate. However, allowing for technological sophistication that is driven by the cumulative experience in producing a final good, enhanced protection can have a negative effect on growth by increasing the share of monopolized sectors. Because the scale of production falls as a result of monopoly pricing, the experience accumulation declines with stronger protection of IPR. As a result, stronger IPR decreases the productivity of the final sector, the associated demand for innovation, and economic growth. This paper shows that, if the latter dominates the former, IPR protection is not growth enhancing.

In recent decades, the broader issue of intellectual property rights (IPR) protection has been at the center of public policy debates. A major argument in favor of stronger IPR is that it stimulates economic growth by protecting innovators from imitation, thereby encouraging innovation. In fact, many countries have strengthened their protection of IPR by reforming their patent systems. However, although this view is widely accepted, recent work, both theoretical and empirical, indicates that, in a closed economy, the relationship between IPR protection and economic growth is actually not so clear.1 This paper shows, in line with the recent work, that IPR protection may not enhance economic growth in an endogenous growth model with costless imitation: that is, ‘stronger is always better’ is incorrect. The crucial assumption in the model is that the accumulation of experience gained by using intermediate machinery improves the productivity of final good firms that make use of this machinery as an input, through the learning by experience effect. 2 Although the literature has studied the effects of IPR protection on economic growth and the economic implications of learning by experience separately, 3 this paper finds an important link between them as described in the following. A common perception is that tightening the protection of IPR increases the expected duration of monopoly and the associated incentive to innovate. A large incentive to innovate enhances the growth rate. However, allowing for technological sophistication that is driven by the cumulative experience of using machinery, tightened protection can have a negative effect on growth. Because tightening IPR increases the proportion of monopolized sectors and monopolistic pricing reduces the level of production, the accumulation of experience is reduced, producing a decline in final sector productivity. Less productive final output firms imply smaller demand for intermediate machinery because intermediates are bought only by final firms in the model presented below. Finally, this reduced demand in turn weakens the incentive to innovate new machinery as a source of economic growth. If the latter dominates the former, IPR protection is not growth enhancing. More specifically, the long-run rate of innovation has an inverse-U shape as a function of the rate of imitation, which is an inverse measure of IPR protection, when the intensity of accumulated experience in the final sector is sufficiently high. The conclusion of the present paper emphasizes a role for relaxing IPR protection as a growth-enhancing policy. The issues of IPR protection often, as mentioned above, are raised in current discussions on development of countries around the world. Consequently, the result of this paper can help to understand the pros and cons of IPR and inform policy discussions about IPR4: the inverted U-shaped relationship between innovation and IPR protection suggests that too strong as well as too weak protection hurts the incentive to innovate: rather a balanced approach is required for innovation and growth. The result presented here is related to Aghion et al. (2005) who find strong evidence of an inverted-U relationship between competition and innovation by using panel data. Since a strengthening of IPR implies reduced competition in the current model, the finding of the current paper is consistent with the evidence by Aghion et al. (2005). Also related is recent empirical literature on institutions and growth, which investigates the relationship between initial institutional quality and growth rates (Hall and Jones, 1999 and Acemoglu et al., 2001). Many papers have examined the effects of IPR protection on economic growth and social welfare in endogenous growth models. Helpman (1993) investigates the effects of IPR protection on welfare and growth by allowing for exogenous imitation in a variety expansion model, with an innovative country and an imitative country. Helpman shows that strengthening IPR in an imitative country need not stimulate innovations in innovative country in the long run.5 Following Helpman (1993), there have been many studies of how IPR protection affects economic growth in closed economy models. Received wisdom in the existing literature is that in a closed economy model, tightening IPR necessarily enhances innovation and economic growth. For example, Kwan and Lai (2003) incorporate the exogenous imitation rate into a lab-equipment version of variety expansion models to examine how IPR protection affects welfare and growth. Iwaisako and Futagami (2003) show that extending patent length enhances economic growth in the variety expansion model of Romer (1990). These closed economy models conclude that strengthening IPR always enhances economic growth. However, as I have already mentioned, most recent papers have indicated that the protection of IPR does not necessarily enhance growth even in a closed economy model, as in the current paper. Horii and Iwaisako (2007) use the average growth rate from 1966 to 2000 to indicate that it is difficult to find a positive relationship between IPR protection and the growth rate, and Gould and Gruden (1996) show a positive but ‘weak’ relationship between them. To explain this fact, Horii and Iwaisako (2007) construct a quality ladder model where strengthened protection can depress the incentive to innovate. Koléda (2005) shows that the effect of patent novelty requirements on growth can be inverse U-shaped, which implies that tightening the IPR protection dampens economic growth for a range of stronger novelty requirements. The current paper presents a mechanism through which stronger IPR protection depresses economic growth by focusing on learning by experience, which has not been stressed in the literature on IPR and growth. The present model is close in spirit to that of Romer (1986), the seminal paper in the endogenous growth literature. Romer (1986) assumes that knowledge creation is a by-product of investment, using Arrow's (1962) setup. The common feature is that technological sophistication arises from the externalities resulting from learning by experience from using intermediate products (machines). Whereas Romer (1986) notes temporary experience, the present model focuses on cumulative experience, as in most models in the literature on learning by experience (e.g., Arrow, 1962, Fudenberg and Tirole, 1983 and Dasgupta and Stiglitz, 1988). Specifically, I assume that final sector productivity increases with a weighted sum of the amount of intermediate goods used up to the present period. The formulation used here is much closer to Arrow's (1962) original setup of learning by doing, which assumes that production cost decreases with cumulative gross investment up to the present. Also related is a paper by Bessen and Maskin (2006), which shows that patent protection may reduce overall innovation and welfare if innovation is sequential and complementary.6 Although the implications in Bessen and Maskin's paper are similar to the one presented here, their purpose is different from mine in that they are not interested in the effects of strengthening IPR on the macroeconomy. Other contributions of this paper are associated with transitional dynamics. One is related to the temporary effects of stronger IPR on the transitional path: a strengthening of IPR increases the growth rate of consumption temporarily, because of the increased expected duration of monopoly. Therefore, in the model, the effects of IPR in the long run and in the short run can be quite opposite. A strengthening of IPR raises the rate of consumption growth initially, but it may eventually fall below the previous level. It is also pointed out that, in this case, IPR policy changes can destabilize the economy. Another contribution is that the transitional path can be oscillatory due to interactions between innovation and the accumulation of experience. The fraction of monopolized sectors increases if the rate of innovation is high enough to exceed the exogenous rate of imitation. Applying the same logic mentioned above, this depresses the accumulation of experience and productivity growth in the final sector, leading to a fall in demand for innovation. As a consequence, the rate of innovation declines gradually when it is at higher levels. The rest of this paper is organized as follows. The next section presents a basic framework. Section 3 investigates determinants of the long-run growth, and Section 4 verifies the properties of the transitional dynamics. Section 5 concludes.

This paper investigates the effects of IPR protection on economic growth in a variety expansion model of endogenous growth. The crucial assumption is that experiences accumulate on using machinery. This assumption generates a negative relationship between tightening IPR and growth, in contrast to most models in the existing literature on growth and IPR protection. The logic behind this interesting result is as follows. Tightening IPR increases the fraction of monopolized sectors. Experience accumulation decreases with a greater number of monopolized sectors, because production levels are lower in a monopolized sector than in a competitive sector. This implies smaller demand for new intermediate goods, which leads to a lesser incentive to innovate. The result of this paper is that the relationship between IPR protection and innovation has an inverted-U shape when the impact of accumulated experience on productivity is large enough. This result suggests a role for relaxing IPR protection as a growth-enhancing policy. Due to the inverted U-shaped relationship between IPR protection and growth, both too strong and too weak protection hurts innovation and the resulting growth: instead, a balanced approach is required for growth. This can provide insight into the role of IPR protection in economic growth, a topic often raised in public policy discussions. This paper also shows that the equilibrium growth rate can be maximized when there is no IPR protection if the natural rate of imitation, which is determined by the economy's fundamentals, is low enough. Therefore, preferred growth-enhancing policies can vary across countries with different potential imitation rates: in countries where imitation hardly takes place, there is no need to protect IPR for innovation and economic growth.