非线性健康保险合同中的即期价格偏误

中文摘要

我们研究了非线性的健康保险计划相关文献中存在的一种表面上的分歧：面对同一类型保单的消费者，在回应某一保单特征——年末保障重置——时显得具有前瞻性且理性，但在回应另一特征——即当期价格以非线性方式取决于年初至今的支出——时却并非如此。我们利用来自统一制度环境内的政策变动以及覆盖全人群的数据。我们在实证上复制了这两种现象：消费者既会因年末重置而调整其购买时点，也会在保障年度内对即期价格反应过度。然而，重要的是，我们表明年末行为同样源于对短期价格的过度关注。具体而言，在给定真实预期价格变动的情况下，消费者的反应完全来自与保障年度重置相关的大幅且显著的即期价格变化。我们发现，流动性约束——而非计划理解能力和认知能力下降——对于理解即期价格偏误十分重要。

Abstract

We study an apparent schism in the literature concerned with non-linear health insurance plans: consumers exposed to the same type of policy appear forward-looking and rational in their response to one policy feature – the end-of-year coverage reset – but not to another – that current prices depend on the year-to-date spending in a non-linear fashion. We exploit policy variation from within a unified institutional environment and uses of population-wide data. We replicate both phenomena empirically: consumers both shift the timing of their purchases in response to the end-of-year reset and react excessively to spot prices during the coverage year. Importantly, however, we show that also the end-of-year behavior is due to over-attention to short-run prices. Specifically, consumers respond entirely to the large and salient change in the spot price in connection with the reset of the coverage year, conditional on the true expected price change. We find that liquidity constraints, rather than plan literacy and cognitive decline are important for understanding the spot price bias.