Patent Policy in an Endogenous Growth Model

We investigate how the patent policy affects economic growth and social welfare based on an endogenous growth model with R&D activities. We show that the patent length that maximizes the social welfare is finite. Moreover, by introducing compulsory licensing, we also show that the patent length that maximizes the social welfare is not infinite even if the royalty rate can be controlled. Received June 29, 2001; revised version received February 5, 2002 Published online: February 17, 2003 We wish to thank two anonymous referees for their constructive comments. We also thank Akira Yakita for his helpful comments.     

FISCAL POLICY IN AN ENDOGENOUS GROWTH MODEL WITH PUBLIC CAPITAL AND POLLUTION

This paper studies the growth and welfare effects of fiscal policy in an endogenous growth model with public capital and environmental pollution. I assume that pollution is due to aggregate production, and that it does not have a direct effect on production but only reduces household utility. I study the growth effects of fiscal policy for the model on the balanced growth path, taking transition dynamics into account. I then analyse the welfare effects of fiscal policy along the balanced growth path. Finally, I show how the fiscal parameters must be set so that the competitive economy replicates the social optimum.     

Human capital use,innovation, patent protection,and economic growth in multiple regions

We provide the first theoretical analysis of the effects of human capital use, innovative activity, and patent protection, on economic growth in a model with many regions. In each region, consumers have constant relative risk-aversion preferences, there is no human capital growth, and there are three kinds of manufacturing activities involving the production of blueprints for inputs (machines), the inputs themselves, and a single final consumption good. Our analysis generates four results. For any given region, we first describe the balanced growth path (BGP) equilibrium and show that the BGP growth rate depends negatively on the rate at which patents expire. Second, we characterize the transitional dynamics in our model. Third, we determine the value of the patent expiry rate that maximizes the equilibrium growth rate of a region. Finally, we show that a policy of offering perpetual patent protection does not necessarily maximize social welfare in a region.     

最优专利制度研究

本文构建了一个动态一般均衡模型来研究最优专利长度和最优专利宽度的问题。研究结论表明,最优的专利长度和专利宽度都是有限的。专利长度的增加会通过促进创新来提高社会福利水平,同时,也会导致市场扭曲,从而降低社会福利水平,但随着专利长度的不断增加,前者的效应会小于后者的效应,因此,有限的专利长度是最优的。有效的专利宽度应该一方面使得模仿产品的质量水平不要太低,从而保证模仿产品对专利产品形成潜在的威胁,逼迫专利产品的价格低于垄断价格,减小市场扭曲;另一方面使得模仿产品的质量不要太高,从而保证专利产品能够制定较高的垄断价格,促进创新。     

Effects of a blocking patent on R&D with endogenous survival activities

This study analyzes the effect of strengthening patent protection for innovation and economic growth by introducing a blocking patent into the endogenous growth model developed by Furukawa (Econ Lett 121(1):26–29, 2013a), which features survival activity of patent holders in the R&D sector with a variety-expansion model. Results show that strengthening patent protection can raise the economic growth rate and social welfare through an endogenous survival investment. Additionally, this study examines the effects of increasing subsidies for R&D. We find that increasing R&D subsidy rate can negatively affect economic growth and social welfare because of the investment for survival activities. This result shows the novel role of a blocking patent in determining innovation effects of R&D subsidies. Furthermore, we analyze the effect of patent breadth which is another patent instrument in this model on innovation and economic growth. Results show that the growth and welfare effects of the profit-division rule and the subsidy rate for R&D may vary with the size of patent breadth.     

Dynamic price competition

We consider the model of price competition for a single buyer among many sellers in a dynamic environment. The surplus from each trade is allowed to depend on the path of previous purchases, and as a result, the model captures phenomena such as learning by doing and habit formation in consumption.We characterize Markovian equilibria for finite and infinite horizon versions of the model and show that the stationary infinite horizon version of the model possesses an efficient equilibrium where all the sellers receive an equilibrium payoff equal to their marginal contribution to the social welfare.     

PRODUCTIVE GOVERNMENT SPENDING,PATTERNS OF SPECIALIZATION AND ECONOMIC GROWTH IN A SMALL OPEN ECONOMY*

Constructing a two‐sector small open endogenous growth model with productive government spending, this paper examines patterns of specialization and the growth effects of fiscal policy. It is shown in this model that a change in income tax rate can cause a change in an equilibrium pattern of specialization. Because of this property, the relationship between the tax rate and the growth rate yields either a humped shape or a two‐humped shape, depending on world commodity prices. We also show that the growth maximizing tax rate is not necessarily equal to the tax rate that maximizes the level of social welfare.     

Population dynamics and utilitarian criteria in the Lucas–Uzawa Model

This paper introduces population growth in the Uzawa–Lucas model, analyzing the implications of the choice of the welfare criterion on the model's outcome. Traditional growth theory assumes population growth to be exponential, but this is not a realistic assumption (see Brida and Accinelli, 2007). We model exogenous population change by a generic function of population size. We show that a unique non-trivial equilibrium exists and the economy converges towards it along a saddle path, independently of population dynamics. What is affected by the type of population dynamics is the dimension of the stable manifold, which can be one or two, and when the equilibrium is reached, which can happen in finite time or asymptotically. Moreover, we show that the choice of the utilitarian criterion will be irrelevant on the equilibrium of the model, if the steady state growth rate of population is null, as in the case of logistic population growth. Then, we show that a closed-form solution for the transitional dynamics of the economy (both in the case population dynamics is deterministic and stochastic) can be found for a certain parameter restriction.     

UNIQUENESS AND INDETERMINACY OF THE EQUILIBRIUM GROWTH PATH IN THE UZAWA‐LUCAS MODEL WITH SECTOR SPECIFIC EXTERNALITIES*

We introduce sector specific external effects of human capital on production in an otherwise Uzawa‐Lucas model of endogenous growth; and show that the problem of indeterminacy of the competitive equilibrium growth path does not exist even if the production function satisfies the increasing returns to scale at the social level.     

Patent term extensions and commercialization lags in the pharmaceutical industry: A growth-theoretic analysis

Due to the lags in commercialization, the effective life of a patent is generally less than its statutory term. We introduce commercialization lags into the Schumpeterian growth model and explore the effects of patent term extensions on pharmaceutical R&D and social welfare. Our results show that extending patent terms stimulates the consumption of homogeneous goods but generates an ambiguous effect on the consumption of pharmaceuticals. When patent extensions have an inverted-U effect on social welfare, the optimal patent extension increases with the length of commercialization lags but decreases with the input intensity of commercialization lags. Finally, we calibrate the model and find that increasing patent breadth reduces the optimal patent extension.     

Asymmetric Information,Auditing Commitment,and Economic Growth

We analyze in this paper the growth and welfare consequences stemming from the lack of auditing commitment in a credit market with costly state verification. By studying two endogenous growth models, one of which allows lenders to commit to costly auditing strategies, whereas the other does not, we show that the inability to commit serves as a source of informational friction that results in more stringent contractual terms, which, in turn, result in lower capital accumulation, growth, and welfare. From the policy perspective, our analysis suggests a new micro‐economic channel through which institutional failings hinder economic growth and social welfare.     

LONG‐RUN GROWTH AND WELFARE EFFECTS OF TAX REFORM

This paper introduces an endogenously‐determined fertility rate into a Romer‐type endogenous growth model and, accordingly, investigates the effects on fertility, economic growth and social welfare of a revenue‐neutral tax reform that involves switching from an income tax to a consumption tax. We show that, in a departure from the existing literature, tax reform could be harmful, rather than favourable, to both growth and welfare, due to an endogenous fertility rate. We also conduct a simple numerical analysis to investigate under what conditions the negative effect on growth and welfare occurs.     

A golden rule of public finance or a fixed deficit regime?: Growth and welfare effects of budget rules

In this paper, we compare growth and welfare effects of various budget rules within an endogenous growth model with productive public capital, utility enhancing public consumption and public debt. We find that introducing a fixed deficit regime does not affect the long run growth rate compared to a balanced budget while establishing a golden rule results in higher growth. Simulations of welfare effects indicate that a golden rule leads to highest welfare followed by a balanced budget and a fixed deficit regime. A maximum fraction of deficit financed public investment is derived. Varying the intertemporal elasticity of substitution shows that economies populated by households who have a strong tendency to smooth consumption should adhere to a balanced budget from a welfare point of view.     

Does intellectual monopoly stimulate or stifle innovation?

This study develops an R&D-based growth model with vertical and horizontal innovation to shed some light on the current debate on whether patent protection stimulates or stifles innovation. We analyze the effects of patent protection in the form of blocking patents. We show that patent protection changes the direction of innovation by having asymmetric effects on vertical innovation (i.e., quality improvement) and horizontal innovation (i.e., variety expansion). Calibrating the model and simulating transition dynamics, we find that strengthening the effect of blocking patents stifles vertical innovation and decreases economic growth but increases social welfare due to an increase in horizontal innovation. In light of this finding, we argue that in order to properly analyze the growth and welfare implications of patents, it is important to consider their often neglected compositional effects on vertical and horizontal innovation.     

Growth and welfare effects of monetary policy with endogenous fertility

This paper investigates the economic growth and social welfare implications of monetary policy in an endogenous growth model with endogenous fertility. We show that, in the money-in-the-utility-function framework, endogenous fertility governs the validity of money superneutrality, the transitional dynamics of an anticipated monetary policy, and the optimal monetary policy. Along a balanced growth path, monetary growth increases fertility and reduces the economic growth rate if consumption and real balances are complements or are independent. However, monetary expansion may decrease fertility and increase economic growth if consumption and real balances are substitutes. Generally speaking, the superneutrality of money does not hold in the presence of endogenous fertility. More importantly, with endogenous fertility, the Friedman (1969) rule is no longer a welfare-maximizing monetary policy. We also show that an anticipated inflation induces the transitional dynamics of fertility and the economic growth rate even though the intertemporal elasticity of substitution equals unity. This differs from the conventional notion in the existing literature.     

HUMAN CAPITAL ACCUMULATION,HOME PRODUCTION AND EQUILIBRIUM DYNAMICS*

In this paper, we construct a three‐sector endogenous growth model in which long‐run growth is propelled by human capital accumulation. We show that although the addition of a home sector to the standard two‐sector endogenous growth model preserves the well‐behaved balanced growth equilibrium properties, it generates new transitional dynamics around the balanced growth path. It is shown that, when there is a positive shock to physical capital, our model is more likely to exhibit paradoxical growth than are standard multisector endogenous growth models that exclude home production. Our analysis adds new results to those from the related literature on leisure.     

Runner‐up Patents: Is Monopoly Inevitable?

Exclusive patents sacrifice product competition to provide firms incentives to innovate. We characterize an alternative mechanism whereby later inventors are allowed to share the patent if they discover within a certain time period of the first inventor. These runner‐up patents increase social welfare under very general conditions. Furthermore, we show that the time window during which later inventors can share the patent should become a new policy tool at the disposal of the designer. This instrument will be used in a socially optimal mix with the breadth and length of the patent and could allow sorting between more or less efficient firms.     

Government spending and growth in second-best economies

This paper extends public spending-based growth theory along three directions: we assume a logistic trajectory for the ratio of government expenditure to aggregate income, self-limiting population change, and exogenous technological progress. By focusing on the choices of a benevolent social planner we find that, if the inverse of the intertemporal elasticity of substitution in consumption is sufficiently high, the ratio of consumption to private physical capital converges towards zero when time goes to infinity. Depending on the form of the underlying aggregate production function and on whether, for given production function, technological progress equals zero or a positive constant, our model may or may not yield an asymptotically balanced growth path (ABGP) equilibrium. When there is no exogenous technological progress, an equilibrium where population size, the ratio of government spending to aggregate income and the ratio of consumption to private physical capital are all constant does exist and the equilibrium is a saddle point. In case of positive technological progress numerical simulations show that the model still exhibits an ABGP equilibrium.     

Economic Growth,Public Debt and Welfare: Comparing Three Budgetary Rules

Abstract. We present an endogenous growth model with externalities of capital and elastic labor supply where we allow for public debt and welfare‐enhancing public spending. We analyze different debt policies as regards convergence to a balanced growth path and their effects on long‐run growth and welfare. Three budgetary rules are considered: the balanced budget rule, a budgetary rule where debt grows in the long run but at a rate lower than the balanced growth rate and a rule where public debt grows at the same rate as all other economic variables but where it guarantees that the intertemporal budget constraint is fulfilled.     

RE‐EXAMINATION OF THE GROWTH‐ENHANCING BUBBLE

We investigate the growth and welfare effects of the bubble that arise on equities on newly created firms by R&D activities. Considering an economy where the input to the R&D sector is the final goods financed by the savings of the household sector, we show that such a bubble has a growth‐enhancing effect under the condition opposite to the previous literature. We also explore the characteristics of the steady state equilibrium with the bubble and demonstrate that there can be dual bubbly equilibria, one of which is unstable and the other stable, and that the growth and welfare effects of an unexpected permanent change in the initial bubble are very different depending on which equilibrium the economy stays in.