We examine how the spatial and social proximity of inventors affects access to knowledge, focusing especially on how the two forms of proximity interact. Employing patent citation data and using same-MSA and co-ethnicity as proxies for spatial and social proximity, respectively, we estimate a...

We study the impact of small firms on innovation in regions where large labs are present. Small firms generate demand for specialized services that lower entry costs for others. This effect is particularly relevant in the presence of large firms that spawn spin-outs caused by innovations deemed...

We examine variation in the concentration of inventive activity across 72 of North America's most highly innovative locations. In 12 of these areas, innovation is particularly concentrated in a single, large firm; we refer to such locations as "company towns". We find that inventors employed by...

The development prospects of a poor country or region depend in part on its capacity for innovation. In turn, the productivity of its innovators, whom are often concentrated around urban centers, depends on their access to technological knowledge. The emigration of highly skilled individuals...