Medicare Part D: Are Insurers Gaming the Low Income Subsidy Design?
研究了医疗保险D部分中，保险公司如何通过操纵低收入参保者的补贴来扭曲保费并增加项目成本，利用前五年的计划数据发现大型保险公司的定价策略扭曲，工具变量估计表明补贴可操纵性指数变化能解释2006-2011年间大部分保费增长。
This paper shows how in Medicare Part D insurers' gaming of the subsidy paid to low-income enrollees distorts premiums and raises the program cost. Using plan-level data from the first five years of the program, I find multiple instances of pricing strategy distortions for the largest insurers. Instrumental variable estimates indicate that the changes in a concentration index measuring the manipulability of the subsidy can explain a large share of the premium growth observed between 2006 and 2011. Removing this distortion could reduce the cost of the program without worsening consumer welfare.