Is Mobility of Technical Personnel a Source of R&D Spillovers?

Labor mobility is often considered to be an important source of knowledge externalities, making it difficult for firms to appropriate returns to R&D investments. In this paper, I argue that inter-firm transfers of knowledge embodied in people should be analyzed within a human capital framework. Testing such a framework using a matched employer-employee data set, I find that the technical staff in R&D-intensive firms pays for the knowledge they accumulate on the job through lower wages in the beginning of their career. Later they earn a return on these implicit investments through higher wages. This suggests that the potential externalities associated with labor mobility, at least to some extent, are internalized in the labor market.