University Patenting: Estimating the Diminishing Breadth of Knowledge Diffusion and Consumption

The rate of university patenting increased dramatically during the 1980s. To what extent did the knowledge flow patterns associated with public sector inventions change as university administrators and faculty seemingly became more commercially oriented? Using a Herfindahl-type measure of patent assignee concentration and employing a difference-in-differences estimation to compare university to firm patents across two time periods, we find that the university diffusion premium (the degree to which knowledge flows from patented university inventions are more widely distributed across assignees than those of firms) declined by over half during the 1980s. In addition, we find that the university diversity premium (the degree to which knowledge inflows used to develop patented university inventions are drawn from a less concentrated set of prior art holders than those used by firms) also declined by over half. Moreover, in both cases the estimated increase in knowledge flow concentration is largely driven by universities experienced in patenting, suggesting these phenomena are not likely to dissipate with experience.