Woolley J M
J Health Econ. 1989 Dec;8(3):271-91. doi: 10.1016/0167-6296(89)90022-2.
Past empirical research has associated higher prices (and potentially profits) with less concentrated hospital markets. This has led to consternation among policymakers who must decide whether or not to apply traditional antitrust guidelines to hospital mergers. Due to the inherent flaws of accounting data, an 'event study' methodology is used to examine the effects of merger related announcements on the competitors' stock price returns. The results provide evidence that events which promote mergers increase the profits of competitors, while events which deter mergers decrease them. Furthermore, the greater the merger impact on local hospital markets, the stronger the effect.
过去的实证研究表明，医院市场集中度越低，价格（以及潜在利润）越高。这让政策制定者感到困惑，他们必须决定是否对医院合并应用传统的反垄断准则。由于会计数据存在固有缺陷，因此采用“事件研究”方法来检验与合并相关的公告对竞争对手股价回报的影响。结果表明，促进合并的事件会增加竞争对手的利润，而阻碍合并的事件则会降低利润。此外，合并对当地医院市场的影响越大，这种效应就越强。
