This study extended the endogenous growth model of Coe and Helpman
(1995) to examine the effects of trade and human capital on R&D spillovers
in 22 OECD countries (1981 to 2011). The analysis confirmed that trade is an
indirect channel of R&D spillovers. In addition, TFP is negatively influenced
by foreign R&D stocks of G7 countries, and positively by those of non-G7
countries. Furthermore, Human capital promotes technology catching up. The
implications of this study are as follows. In order to increase TFP productivity,
it is necessary to accumulate human capital along with R&D expenditure, and
to establish a proper international trade network so that foreign R&D
investments have positive effects on domestic TFP.