Knowledge Spillovers through Networks of Scientists

In this article, I directly test the hypothesis that interactions between inventors of different firms drive knowledge spillovers. I construct a network of publicly traded companies in which each link is a function of the relative proportion of two firms’ inventors who have former patent collaborators in both organizations. I use this measure to weigh the impact of R&D performed by each firm on the productivity and innovation outcomes of its network linkages. An empirical concern is that the resulting estimates may reflect unobserved, simultaneous determinants of firm performance, network connections, and external R&D. I address this problem with an innovative IV strategy, motivated by a game-theoretic model of firm interaction. I instrument the R&D of one firm’s connections with that of other firms that are sufficiently distant in network space. With the resulting spillover estimates, I calculate that among firms connected to the network the marginal social return of R&D amounts to approximately 112% of the marginal private return.

On the Returns to Invention within Firms: Evidence from Finland

In this paper we merge individual income data, firm-level data, patenting data, and IQ data in Finland over the period 1988-2012 to analyze the returns to invention for inventors and their coworkers or stakeholders within the same firm. We find that: (i) inventors collect only 8 percent of the total private return from invention; (ii) entrepreneurs get over 44 percent of the total gains; (iii) bluecollar workers get about 26 percent of the gains and the rest goes to white-collar workers. Moreover, entrepreneurs start with significant negative returns prior to the patent application, but their returns subsequently become highly positive.

The Effect of Education on Crime: Evidence from Prison Inmates, Arrests, and Self-Reports

We estimate the effect of education on participation in criminal activity using changes in state compulsory schooling laws over time to account for the endogeneity of schooling decisions. Using Census and FBI data, we find that schooling significantly reduces the probability of incarceration and arrest. NLSY data indicate that our results are caused by changes in criminal behavior and not differences in the probability of arrest or incarceration conditional on crime. We estimate that the social savings from crime reduction associated with high school graduation (for men) is about 14–26 percent of the private return.