Can Propensity-Score Methods Match the Findings from a Random Assignment Evaluation of Mandatory Welfare-to-Work Programs?
利用六个州的随机分配研究数据，评估非实验方法（尤其是倾向得分匹配）在估计强制性福利到工作计划效果时的准确性，并探讨其能否替代随机分配。
This paper assesses nonexperimental estimators using results from a six-state random assignment study of mandatory welfare-to-work programs. The assessment addresses two questions: which nonexperimental methods provide the most accurate estimates; and do the best methods work well enough to replace random assignment? Three tentative conclusions emerge. Nonexperimental bias was larger in the medium run than in the short run. In-state comparison groups produced less average bias than out-of-state comparison groups. Statistical adjustments did not consistently reduce bias, although some methods reduced the estimated bias in some circumstances and propensity-score methods provided a specification check that eliminated some large biases. 2004 President and Fellows of Harvard College and the Massachusetts Institute of Technology.