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双重差分法作为一种计量模型，其本身不解决内生性问题，双重差分法解决内生性问题，本质上仍然依赖于干预或政策冲击本身的外生性。标准 did（standard did）双重差分的核心是通过构造交互项来. So it's not hard to understand why this man was enraged and feigned strength after losing face. 简介双重差分模型 (difference in difference，did) 是政策评估的常用方法。其中，经典的 did 方法通常拥有两期 (处理前和处理后) 和两组 (处理组和对照组) 数据。在具体应用中，考虑到个体和时间异.