同上问~

http://www.principlesofeconometr ... 4do_files/chap07.do
* open data file
use njmin3, clear
describe
summarize nj d d_nj fte

* DID estimation using sample means
bysort nj d: summarize fte

* DID estimation using regression
reg fte nj d d_nj
estimates store did

lincom _cons + nj
lincom _cons + d
lincom _cons + nj + d  + d_nj
lincom (_cons + nj + d + d_nj)-(_cons + d)-((_cons + nj)-_cons)

* add owner controls
reg fte nj d d_nj kfc roys wendys co_owned
estimates store did2

* add location controls
reg fte nj d d_nj kfc roys wendys co_owned southj centralj pa1
estimates store did3

esttab did did2 did3, b(%10.4f) se(%10.3f) t(%10.3f) r2 ar2 ///
title("Difference in Difference Regressions")

* DID regression using only balanced sample
reg fte nj d d_nj if !missing(demp)

非常感谢~

h diff