Editorial Note: This article is written with editorial review and topic relevance in mind.
在传统 did 模型中，所有单位的政策时间一致，安慰剂检验只需在所有单位中随机抽取固定数量的若干单位作为实验组便可。但是，在多期 did 中每个单位的政策时间不同，该种方法便不再.
Things to know about the retrial of Karen Read in the killing of her
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