INNOVATION AND DIFFUSION OF MEDICAL TREATMENT
构建并估计了一个动态结构需求模型，研究产品特性如何因消费者选择而内生演化，发现个体忽视自身对创新的影响导致创新效率低下，并以艾滋病药物为例，证明补贴实验性治疗可提升社会福利并减少健康群体间的效用不平等。
Abstract We develop and estimate a dynamic structural model of demand in a setting where product characteristics endogenously evolve in response to aggregate consumer choices. The direction and speed of innovation are inefficient because individuals do not account for their influence on innovation, creating an externality. Our application focuses on drugs invented to combat human immunodeficiency virus; they differ in their efficacy and propensity to cause side effects. We find that the externality is quantitatively important; temporarily subsidizing the experimental treatment would have increased average social welfare by improving average health and would have reduced inequality in lifetime utility across health groups.