Firm age and innovation
研究了企业年龄与创新质量的关系，发现企业年龄越大，专利技术质量越低，尤其在技术活跃地区更明显；企业每增加一年，研发强度对市场价值的提升效果下降超过3%。
We examine how firm age relates to innovtion quality, and how this relationship varies depending on the nature of technology. Using data on patents of COMPUSTAT firms, we find that firm age is negatively related to technical quality, and that this effect is greater in technologically active areas. The economic implication of this effect is substantial; each additional year reduces the impact of a 10% increase in R&D intensity on the firm's market value by over 3%.