Markets for inventors: Learning-by-hiring as a driver of mobility

Hiring away inventors has long been recognized as a way of learning used by innovative firms. This paper claims that the characteristics of the knowledge accumulated by an inventor at his current employer affect what hiring firms can learn from him. The implication is that some inventors are more likely to be hired away than their coworkers. We analyze the relationship between the type of knowledge embodied by inventors working at IBM and their probability of moving. Relying on patent data to track the movement of inventors across firms and to characterize the kind of know-how they hold, we identify the following drivers of inventor mobility: the quality of their work; the complementarity of their knowledge with that of other inventors; and, to a lower extent, their expertise in the firm's core areas in which the firm is not a dominant player. Results confirm the role of knowledge characteristics behind the mobility of research and development personnel and suggest that learning is a relevant force in the market for inventors.