Zwanziger Jack, Mukamel Dana B, Indridason Indridi
Department of Community and Preventive Medicine, University of Rochester School of Medicine and Dentistry, NY 14642, USA.
Inquiry. 2002 Spring;39(1):56-66. doi: 10.5034/inquiryjrnl_39.1.56.
Previous studies of nursing home markets have assumed that a nursing home's market is coincident with the boundaries of the county in which it is located. We test this assumption by using the zip code of residence for Medicare beneficiaries admitted into a nursing home in New York state in the periods 1992-93 and 1996-97. We find that nursing homes located in urban areas have markets that are a fraction of the size of the county in which they are located. We calculate the Herfindahl-Hirschman Index (HHI) to measure the competitiveness of each nursing home's market. This shows that nursing home markets tend to be more concentrated than those that result from assuming countywide markets. These results suggest that studies of nursing home markets should not use counties as markets.
以往对养老院市场的研究假定，一家养老院的市场与其所在县的边界一致。我们通过使用1992 - 93年和1996 - 97年期间入住纽约州养老院的医疗保险受益人的居住邮政编码来检验这一假设。我们发现，位于城市地区的养老院的市场规模只是其所在县规模的一小部分。我们计算赫芬达尔 - 赫希曼指数（HHI）来衡量每个养老院市场的竞争力。这表明，养老院市场往往比假定全县范围市场时的情况更加集中。这些结果表明，对养老院市场的研究不应将县作为市场。
