Do competition and managed care improve quality?
利用1992-1997年美国16个州的医院面板数据，研究管理式医疗渗透率和医院竞争对医疗质量的影响，发现管理式医疗渗透率提高反而提升部分质量指标，而医院市场集中度提高则降低质量。
In recent years, the US health care industry has experienced a rapid growth of managed care, formation of networks, and an integration of hospitals. This paper provides new insights about the quality consequences of this dynamic in US hospital markets. I empirically investigate the impact of managed care and hospital competition on quality using in-hospital complications as quality measures. I use random and fixed effects, and instrumental variable fixed effect models using hospital panel data from up to 16 states in the 1992-1997 period. The paper has two important findings: First, higher managed care penetration increases the quality, when inappropriate utilization, wound infections and adverse/iatrogenic complications are used as quality indicators. For other complication categories, coefficient estimates are statistically insignificant. These findings do not support the straightforward view that increases in managed care penetration are associated with decreases in quality. Second, both higher hospital market share and market concentration are associated with lower quality of care. Hospital mergers have undesirable quality consequences. Appropriate antitrust policies towards mergers should consider not only price and cost but also quality impacts.