Hello everyone,
I am trying to run a diff in diff in stata. I have more than 3,500 obs, some of them regarding the same individual in two different years, some of them regarding an individual in one of the two years. I have created an "id" variable and i sorted it, so now I can identify the individuals with two obs. The problem is I want to retain only these obs, the panel ones, and drop the obs regarding the individuals analyzed only in one year. Which command should I use? I'm relatively new to Stata, so sorry if the question is utterly trivial and thank you for the answers!