Hi all,

I have a panel data (firm and year). I create Post indicator for states that adopt certain laws. Specifically, I create Post, which is a dummy that takes a value of one in all observations in which the law is in effect, and zero otherwise. This is a staggered adoption (states adopt the laws in different year).


What is the best way to create this difference in difference regression?

DepVar= Post + controls
or
DepVar = Post + Treatment*Post + Treatment + control variables, Treatment indicates states adopting the laws.