The Anatomy of Industry R&D Intensity Distributions
利用行业层面的企业数据，揭示了制造业内企业研发强度分布的一系列规律，并提出了一个简单概率模型来解释这些规律以及研发强度与市场集中度、变异系数等长期观察到的关系。
Using firm data disaggregated by industry, the authors establish a set of regularities in the distribution of firm R&D intensities within manufacturing industries. The authors show how a simple probabilistic process, in which change influences a key unobserved determinant of R&D and firm size conditions the returns to R&D, can account for these regularities and other features of the distributions. The model provides a unified, noncausal explanation of a series of long-observed relationships across mean R&D intensity, market concentration, and the coefficient of variation. It also offers a novel explanation for the inverse relationship between R&D productivity and firm size. Copyright 1992 by American Economic Association.