Reconsideration of discharge data to measure competition in the hospital industry
研究发现，由于医院合并和网络化活动，基于出院数据构建的赫芬达尔指数未能反映所有权变化，导致竞争衡量失真，对纽约州医院的年度普查数据证实了这一点。
Economists have long used state-collected discharge data to construct Hirschman-Herfindahl (HH) indices measuring hospital competition. Since data are collected to determine the facility providing the service rather than ownership, the difference between the number of reporting facilities and the number of competitors has grown over time due to mergers and networking activities. Consequently, the validity of the discharge HH methodology, as currently employed, is in doubt. Comparing the annual census of New York state acute-care hospitals by the State and the American Hospital Association (AHA), we find that it is increasingly important to account for changes in ownership when constructing such indices.