Have R&D Spillovers Changed?

This paper revisits the results of Bloom, Schankerman, and Van Reenen (2013) on the impact of R&D spillovers on growth. We extend their analysis to include an additional 15 years of data on firm R&D and performance, and update the measures of firms’ interactions in technology space and product market space. We show that the magnitude of spillovers appears to have been broadly stable over the past few decades. In comparison to the earlier analysis, indeed we find stronger evidence of strategic complementarity in R&D and a larger gap between the marginal social return and the marginal private return to R&D, with the marginal social return exceeding the marginal private return by a factor of 4.