Call K T, Dowd B, Feldman R, Maciejewski M
University of Minnesota, USA.
Health Care Financ Rev. 1999 Summer;20(4):197-209.
Using 1993 and 1994 data, the authors examine whether beneficiaries who enroll in a Medicare health maintenance organization (HMO), including those enrolling for only a short period of time, have lower expenditures than continuous fee-for-service (FFS) beneficiaries the year prior to enrollment. We also test whether biased selection varies by the level of HMO market penetration and the rate of market-share growth. We find favorable selection associated with enrollment into Medicare HMOs, which declines as market share increases but does not disappear. Among short-term enrollees, we find unfavorable selection, however, selection bias was not sensitive to market characteristics.
作者利用1993年和1994年的数据，研究加入医疗保险健康维护组织（HMO）的受益人，包括那些仅短期参保的人，其支出是否低于参保前一年持续采用按服务付费（FFS）的受益人。我们还测试了选择偏差是否因HMO市场渗透率水平和市场份额增长率而异。我们发现加入医疗保险HMO存在有利选择，这种选择会随着市场份额的增加而下降，但不会消失。然而，在短期参保者中，我们发现了不利选择，不过选择偏差对市场特征并不敏感。
