Research and Development with Asymmetric Firm Sizes
构建了一个研发竞争的理论模型，同时解释了两个经验现象：小企业贡献了不成比例的重大创新，而大企业研发投入绝对值更高但项目更安全、重大创新更少。
This article presents a theoretical model of research and development (R&D) competition among firms. The goal of the model is to simultaneously explain two empirical observations pertaining to the persistence of dominantfirms: small firms make a disproportionate share of major innovations, while largefirms tend to spend more (in absolute terms) on R&D than smallfirms do. In the model here, firms choose investment levels and R&D project riskiness. In equilibrium, a large firm invests more than a smaller firm but, by choosing safer R&D projects, makes fewer major innovations.