Estimating Treatment Effects from Contaminated Multiperiod Education Experiments: The Dynamic Impacts of Class Size Reductions
提出一种估计多阶段随机实验中动态处理效应的策略，处理了损耗和选择性转换等违规问题，并应用于Project STAR数据，发现小班在幼儿园和一年级有认知收益，但之后无显著动态效应。
This paper introduces an empirical strategy to estimate dynamic treatment effects in randomized trials that provide treatment in multiple stages and in which various noncompliance problems arise, such as attrition and selective transitions between treatment and control groups. Our approach is applied to the highly influential four-year randomized class size study, Project STAR. We find benefits from attending small classes in all cognitive subject areas in kindergarten and first grade. We do not find any statistically significant dynamic benefits from continuous treatment versus never attending small classes following grade 1. Finally, statistical tests support accounting for both selective attrition and noncompliance with treatment assignment. © 2010 The President and Fellows of Harvard College and the Massachusetts Institute of Technology.