Evidence of randomisation bias in a large-scale social experiment: The case of ERA
提出了系统考虑随机化偏倚的理论框架，估计了随机化对实际试验参与模式的影响，并提出了非实验方法评估实验效果的代表性，同时扩展了估计量以处理二元结果和选择性调查无应答。
We set out a theoretical framework for the systematic consideration of 'randomisation bias', estimate the causal impact of randomisation on participation patterns in an actual trial, and propose a non-experimental way of assessing the extent to which the experimental impacts are representative of the impacts that would have been experienced by the study sample that would have been obtained in the absence of random assignment. We also extend our estimator to deal with binary outcomes and to account for selective survey non-response, and explore partial and point identification of the parameter of interest under alternative assumptions on the selection process.