Please Call Again: Correcting Nonresponse Bias in Treatment Effect Models
提出一种结合Heckit和Lee边界方法的样本选择校正程序，利用调查中联系个体的尝试次数信息来纠正无应答偏差，并在应答率低且不平衡的求职实验中进行应用。
We propose a novel selectivity correction procedure to deal with survey attrition, at the crossroads of the Heckit and of the bounding approach of Lee (2009). As a substitute for the instrument needed in sample selectivity correction models, we use information on the number of attempts that were made to obtain response to the survey from each individual who responded. We obtain set identification, but if the number of attempts to reach each individual is high enough, we can come closer to point identification. We apply our sample selection correction in the context of a job-search experiment with low and unbalanced response rates.