First Movers and Follow-on Invention: Evidence from a Vector Space Model of Invention

This paper estimates the causal effect of being a first mover in the patent space by charting invention in a vector space model of technological relatedness and timing. Relative to close second movers, we find that first movers are more likely to prosecute a patent application to issuance and to pursue more follow-on invention. Invention novelty, however, is associated with being less likely to prosecute a patent application to issuance and with less follow-on invention. Moreover, the importance of being a first mover depends on how novel the invention is: the marginal effect of being a first mover increases when pursuing more novel invention, even though the overall likelihood of prosecuting a patent to issuance continues to decline with more novelty. We provide open access to our data for follow-on work by other researchers.