Spillovers in Space: Does Geography Matter?
利用美国企业面板数据，研究了地理、技术和产品市场三种研发溢出对生产力的影响，发现地理和技术溢出重要，且企业研究者的地理位置比总部更重要。
Using U.S. firm level panel data we simultaneously assess the contributions to productivity of three potential sources of research and development spillovers: geographic, technological, and product market (“horizontal”). To do so, we construct new measures of geographic proximity based on the distribution of a firm's inventor locations as well as its headquarters. We find that geographic location is important for productivity, as are technology (but not product) spillovers, and that both intra and inter–regional (counties) spillovers matter. The geographic location of a firm's researchers is more important than its headquarters. These benefits may be the reason why local policy makers compete so hard for the location of local R&D labs and high tech workers.