Estimating Equilibrium in Health Insurance Exchanges: Price Competition and Subsidy Design under the ACA
中文摘要
许多经合组织（OECD）国家日益采用相关监管制度，以构建由公共部门资助的私人健康保险市场。本文结合数据与经济理论，分析保险公司之间的竞争与保费补贴设计在决定均衡结果中的相互作用。我的实证模型纳入了逆向选择、消费者对纵向和横向差异化保险计划偏好的丰富异质性，并允许对定价行为采取不同假设。在美国《平价医疗法案》（ACA）的背景下，我利用加利福尼亚州2014年至2017年间340万次保险计划选择的行政记录，结合计划数据与医疗索赔调查数据，估计了偏好与预期成本的联合分布。对不同定价行为假设的实证比较表明，寡头定价比完全竞争更符合数据。对替代性补贴设计的考察显示，在均衡状态下，将补贴慷慨程度向“年轻无敌者”（自认健康风险低的年轻群体）倾斜，将降低所有参保者的保费，同时提高参保率和利润。
Abstract
Abstract Regulations to design private yet publicly sponsored health insurance markets are increasingly adopted in many OECD countries. Here I combine data and economic theory to analyse the interaction between insurers’ competition and the design of premium subsidies in determining equilibrium outcomes. My empirical model includes adverse selection, rich heterogeneity in preferences for vertically and horizontally differentiated plans and accommodates alternative assumptions on pricing conduct. In the context of the Affordable Care Act in the U.S., I estimate the joint distribution of preferences and expected cost using Californian administrative records on 3.4 million plan choices between 2014 and 2017, combined with plan and survey data on medical claims. An empirical horse race between conduct assumptions favours oligopoly pricing over perfect competition. Considering alternative subsidy designs shows that, in equilibrium, shifting subsidy generosity toward the “young invincibles” would lower premiums for all enrolees while increasing enrolment and profits.