Subsidy Design in Privately Provided Social Insurance: Lessons from Medicare Part D
研究了Medicare处方药计划中补贴机制与保险公司策略的互动，发现现有机制类似固定代金券且福利接近最优，更高效的补贴需保留需求弹性、限制市场势力并保持价格与边际成本的联系。
The efficiency of publicly-subsidized, privately-provisioned social insurance programs depends on the interaction between strategic insurers and the subsidy mechanism. We study this interaction in the context of Medicare's prescription drug coverage program. We find that the observed mechanism is successful in keeping "raise-the-subsidy" incentives relatively low, acts much like a flat voucher, and obtains a level of welfare close to the optimal voucher. Across a range of counterfactuals, we find that more efficient subsidy mechanisms share three features: they retain the marginal elasticity of demand, limit the exercise of market power, and preserve the link between prices and marginal costs.