Ross School of Business, University of Michigan, Ann Arbor, MI 48109, USA.
Health Econ. 2013 Jan;22(1):35-51. doi: 10.1002/hec.1814. Epub 2012 Jan 25.
We use 4 years of data from the retiree health benefits program of the University of Michigan to estimate the effect of price on the health plan choices of Medicare beneficiaries. During the period of our analysis, changes in the University's premium contribution rules led to substantial price changes. A key feature of this 'natural experiment' is that individuals who had retired before a certain date were exempted from having to pay any premium contributions. This 'grandfathering' creates quasi-experimental variation that is ideal for estimating the effect of price. Using regression discontinuity methods, we compare the plan choices of individuals who retired just after the grandfathering cutoff date and were therefore exposed to significant price changes to the choices of a 'control group' of individuals who retired just before that date and therefore did not experience the price changes. The results indicate a statistically significant effect of price, with a $10 increase in monthly premium contributions leading to a 2 to 3 percentage point decrease in a plan's market share.
我们利用密歇根大学退休人员健康福利计划四年的数据，来估计价格对医疗保险受益人的健康计划选择的影响。在我们的分析期间，大学的保费缴纳规则发生了变化，导致价格发生了重大变化。这个“自然实验”的一个关键特征是，在特定日期之前退休的人无需缴纳任何保费。这种“祖父条款”创造了理想的准实验变化，非常适合估计价格的影响。我们使用回归不连续性方法，将那些刚刚在祖父条款截止日期退休、因此面临重大价格变化的人的计划选择与那些刚刚在该日期之前退休、因此没有经历价格变化的“对照组”的选择进行比较。结果表明价格具有显著的影响，每月保费增加 10 美元，会导致计划的市场份额下降 2 到 3 个百分点。
