TY - JOUR AU - Comin,Diego TI - R&D: A Small Contribution to Productivity Growth JF - National Bureau of Economic Research Working Paper Series VL - No. 10625 PY - 2004 Y2 - July 2004 UR - http://www.nber.org/papers/w10625 L1 - http://www.nber.org/papers/w10625.pdf N1 - Author contact info: Diego A. Comin Harvard Business School Soldiers Field Boston, MA 02163 Tel: 617/495-5011 E-Mail: dcomin@hbs.edu AB - In this paper I evaluate the contribution of R&D investments to productivity growth. The basis for the analysis are the free entry condition and the fact that most R&D innovations are embodied. Free entry yields a relationship between the resources devoted to R&D and the growth rate of technology. Since innovators are small, this relationship is not directly affected by the size of R&D externalities, or the presence of aggregate diminishing returns in R&D after controlling for the growth rate of output and the interest rate. The embodiment of R&D-driven innovations bounds the size of the production externalities. The resulting contribution of R&D to productivity growth in the US is smaller than three to five tenths of one percentage point. This constitutes an upper bound for the case where innovators internalize the consequences of their R&D investments on the cost of conducting future innovations. From a normative perspective, this analysis implies that, if the innovation technology takes the form assumed in the literature, the actual US R&D intensity may be the socially optimal. ER -