Department of Economics,University of Tampa,Tampa,FL,USA.
College of Business,University of Tampa,Tampa,FL,USA.
Health Econ Policy Law. 2019 Jul;14(3):374-399. doi: 10.1017/S1744133117000263. Epub 2018 Jan 8.
One goal of the Affordable Care Act is to increase insurance coverage by improving competition and lowering premiums. To facilitate this goal, the federal government enacted online marketplaces in the 395 rating areas spanning 34 states that chose not to establish their own state-run marketplaces. Few multivariate regression studies analyzing the effects of competition on premiums suffer from endogeneity, due to simultaneity and omitted variable biases. However, United Healthcare's decision to enter these marketplaces in 2015 provides the researcher with an opportunity to address this endogeneity problem. Exploiting the variation caused by United Healthcare's entry decision as an instrument for competition, we study the impact of competition on premiums during the first 2 years of these marketplaces. Combining panel data from five different sources and controlling for 12 variables, we find that one more insurer in a rating area leads to a 6.97% reduction in the second-lowest-priced silver plan premium, which is larger than the estimated effects in existing literature. Furthermore, we run a threshold analysis and find that competition's effects on premiums become statistically insignificant if there are four or more insurers in a rating area. These findings are robust to alternative measures of premiums, inclusion of a non-linear term in the regression models and a county-level analysis.
《平价医疗法案》的目标之一是通过提高竞争力和降低保费来增加保险覆盖范围。为了实现这一目标，联邦政府在 34 个选择不建立自己的州立市场的州的 395 个评级区域内建立了在线市场。由于同时性和遗漏变量偏差，很少有分析竞争对保费影响的多元回归研究受到内生性的影响。然而，联合健康保险公司在 2015 年决定进入这些市场，为研究人员提供了一个解决这个内生性问题的机会。我们利用联合健康保险公司进入市场的决定所引起的变化作为竞争的工具，研究了这些市场头两年竞争对保费的影响。我们结合了来自五个不同来源的面板数据，并控制了 12 个变量，发现一个评级区域内有一个以上的保险公司，会导致第二低价位的银计划保费降低 6.97%，这比现有文献中的估计效果还要大。此外，我们进行了一个门槛分析，发现如果一个评级区域内有四个或更多的保险公司，竞争对保费的影响在统计上就变得不显著了。这些发现对于保费的替代衡量标准、回归模型中非线性项的包含以及县级分析都是稳健的。
