Preliminary Results of a Controlled Trial of the Effect of a Prepaid Group Practice on the Outpatient Use of Mental Health Services
基于兰德健康保险研究的随机分配数据，比较预付费团体医疗与按服务收费保险计划对门诊心理健康服务使用的影响，发现按服务收费组支出更高但使用率无差异。
Using data from the Rand Health Insurance Study, which randomly assigned families into a prepaid group practice (PGP) and a fee-for-service insurance plan, this study finds different patterns of outpatient mental health care for the two groups. In the absence of cost sharing, fee-for-service participants are as likely as PGP participants to visit formally trained mental health specialists, but with 2.8 times greater imputed expenditures. Thus, fee-for-service provides more intensive therapy. Because the participants are random samples of the same population, these differences result from institutional differences (and patient incentives for cost sharing) rather than adverse selection.