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So it's not hard to understand why this man was enraged and feigned strength after losing face. 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.

Opeen Jan 24, 2026

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. Look at what james did, all those middle school drama. Did 和事件研究法等确实有别，但是为了方便而且也不歧义，下面就只说 did 了。这当然是极好的，did 方法从获得诺贝尔经济学奖到本科生都能应用的时间并不长。这点也和工具变量法当年的情形类似，.