Growth Theory
R&D spillovers

Neoclassical growth theories viewed capital accumulation as the main endogenous source of output expansion and regarded technological progress as exogenous. In more recent studies, however, innovation both feeds on the stock of knowledge derived from cumulative R&D experience and also contributes to it. In Discussion Paper No. 840, David Coe and Research Fellow Elhanan Helpman develop a model of international trade in goods and services, with foreign direct investment and international exchange of knowledge. A country's productivity depends on its own R&D efforts and those of its trading partners. Its own R&D produces traded and non-traded goods and services that allow it to make better use of its existing resources and thus raise productivity; it also enhances its ability to benefit from foreign technical advances. These provide both the direct benefits of learning about new technologies and materials, production processes or organizational methods, and indirect benefits emanating from imports of goods and services developed by trading partners, both of which can raise domestic productivity.

Coe and Helpman construct domestic and foreign stocks of knowledge for a sample of 21 OECD countries plus Israel during 1970-90 (proxied by their own cumulative R&D expenditures and those of their trading partners) and also calculate measures of domestic total factor productivity from their outputs and labour and capital inputs. They estimate the effects of domestic and foreign R&D capital stocks on productivity to show that the influence of foreign R&D capital stocks increases with the economy's openness. The foreign R&D capital stock is just as important as the domestic R&D capital stock in the smaller countries, while the domestic R&D capital stock dominates in the G7 countries. Finally, Coe and Helpman show that the G7's trading partners appropriate about one-quarter of the world-wide benefits of the G7's investment in R&D.

International R&D Spillovers
David T Coe and Elhanan Helpman


Discussion Paper No. 840, October 1993 (IT)