Addressing self-selection effects in evaluations of mutual help groups and professional mental health services: An introduction to two-stage sample selection models
Addressing self-selection effects in evaluations of mutual help groups and professional mental health services: An introduction to two-stage sample selection models
复制标题
DOI：
10.1016/s0149-7189(96)00028-6
复制
发表时间：
1996-11-01
影响因子：
1.6
通讯作者：
Moos, RH
中科院分区：
文献类型：
--
作者：
Humphreys, K;Phibbs, CS;Moos, RH
由于在相互海带组织的纵向评估中，随机分配条件通常既不可能也不可取，因此必须评估自选择效应的影响，以便准确解释结果数据。调整自选择效应的一种方法是使用协方差分析 (ANCOVA)、偏相关和分层回归等统计程序来控制预测结果的协变量。这种方法具有相当大的威力，但当评估者有兴趣直接对进入项目的过程进行建模并将影响自我选择的因素的信息纳入项目效果的估计时，这种方法就不太有用了。两阶段样本选择模型旨在解决这种情况。这些模型依赖于回归程序，其中在初始方程中对计划参与进行建模，从而产生样本选择校正因子。校正因子包含在预测结果的第二个方程中。这个两阶段程序允许评估者在选择效果的大小和方向的背景下解释专业服务或自助团体观察到的效果。我们在一项关于参加戒酒互诫协会对饮酒行为影响的纵向研究中比较和对比了协变量控制和样本选择模型。版权所有 (C) 1996 爱思唯尔科学有限公司
Because random assignment to conditions is often neither possible nor desirable in longitudinal evaluations of mutual kelp organizations, the influence of self-selection effects must be assessed in order to accurately interpret outcome data. One approach to adjusting for self-selection effects is to control for covariates that predict outcome using statistical procedures such as analysis of covariance (ANCOVA), partial correlations, and hierarchical regression. This approach has considerable power, but is less useful when an evaluator is interested in directly modeling the process of entry into a program and incorporating information on the factors affecting self-selection into estimation of program effects. Two-stage sample selection models are designed to address such situations. These models rely on regression procedures in which program participation is modeled in an initial equation, which yields a sample selection correction factor. The correction factor is included with participation in a second equation that predicts outcome. This two-stage procedure allows the evaluator to interpret the observed effects of a professional service or a self-help group in the context of the magnitude and direction of selection effects. We compare and contrast the covariate control and sample selection models in a longitudinal study of the effects of participation in Alcoholics Anonymous on drinking behavior. Copyright (C) 1996 Elsevier Science Ltd