اثرات رشد بلند مدت سیاست تحقیق و توسعه
Abstract
1- Introduction
2- Second-generation endogenous growth models
3- Empirical analysis
4- Empirical results
5- Conclusions
Acknowledgements
Appendix B. Supplementary data
References
Abstract
We assess the long-run growth effects of public policies to business R&D using data for US manufacturing industries and taking Schumpeterian growth theory as guideline. Our analysis indicates that R&D policy in the form of R&D tax credits fosters the rate of productivity growth over the long-term horizon. This effect is quantitatively important: increasing R&D tax credits by 10% raises the growth rate of labour productivity by 0.4% per year. We show that our findings are robust to controlling for several policy instruments, growth determinants and econometric issues. Moreover, the overall evidence is consistent with the predictions of second-generation fully-endogenous growth models
Introduction
Do changes in public policies aimed at stimulating business R&D lead to higher growth rates of productivity? If any, are these effects long lasting? Taking Schumpeterian growth theory as guideline, this paper addresses these questions by providing econometric evidence on the long-run impact of R&D policy on productivity growth of the United States. Early models of R&D-based growth postulate that the longrun growth rate of productivity is proportional to the level of research undertaken in the overall economy (see, e.g., Romer, 1990; Grossman and Helpman, 1991; Aghion and Howitt, 1992). In these models, any policy change permanently affects the growth rate of productivity. In the mid-1990s, the critique formulated by Jones (1995b) againstthe prediction ofthese models on the scale effect of R&D stimulated the development of an array of second-generation growth models without scale effects. A first strand of studies makes the assumption of diminishing returns to knowledge and predicts that the steady-state level of productivity is an increasing function of the economy’s size (and hence of the amount of R&D), but not its growth rate. Accordingly, R&D policy has no impact on productivity growth in the long run, but only along the transition path. These models are referred to as of semi-endogenous growth as they contend that the growth rate of productivity is ultimately driven by the (exogenous) population growth rate (Jones, 1995a; Kortum, 1997; Segerstrom, 1998). Another line of research known as fully-endogenous growth theory (see, e.g., Dinopoulos and Thompson, 1998; Peretto, 1998; Young, 1998; Aghion and Howitt, 2008, ch. 12) builds upon the insight that, as an economy grows and new varieties are discovered, aggregate R&D effort becomes less effective because it spreads among a greater number of product lines. Productivity growth would depend on the R&D intensity at the firm level, explaining why growth can be stationary despite the increasing resources invested in R&D. Accordingly, any policy that affects R&D intensity has also an impact on the steady-state growth rate.