RISING R&D INTENSITY AND ECONOMIC GROWTH
构建了一个增长模型，解释美国等发达国家研发支出增速持续超过GDP、而人均产出增长率却保持稳定甚至略有下降的现象。模型表明，研发强度不可持续上升的趋势可能长期持续。
Over the past decades, private R&D spending in the United States and other developed countries has been growing faster than gross domestic product. At the same time, the growth rates of per-capita and aggregate output have been rather stable, possibly declining slightly. This article proposes a growth model that can account for the observed phenomenon by explicitly describing competition among technological leaders and followers in individual markets in a way that is consistent with existing studies on firms' motivation to invest in R&D. The model shows the possibility that the unsustainable trend of rising R&D intensity persists for a very long time.