Bounding the Effects of R&D: An Investigation Using Matched Establishment-Firm Data
利用匹配的企业-工厂数据，分析企业研发对工厂生产率的影响，发现母公司研发强度和行业技术溢出效应显著，但溢出效应随研发分散而减弱。
Studies of firm-level data have shown that a firm's RD (2) productivity appears to depend on the intensity of parent firm RD and (3) spillovers of research effects from technologically related firms are significant but also depend on R&D intensity rather than total industry R&D. These results suggest that, despite the externalities created by spillovers of R&D, the `dilution' of R&D across multiple target plants reduces its potency sufficiently that spillovers may not be a source of industry-wide or economy-wide increasing returns.