st: Keep observations in panel data

[s <s.afcha@ub.edu>]

Dear s or S:

This sounds like

bysort id (year) : keep if subsidy == 1 & subsidy[_n+1] == 0 &
subsidy[_n+2] == 0

Nick

P.S. as a native English speaker, frequent reviewer and Editor, I
advise firmly against the English usage "a panel data", which does not
qualify as standard. (It seems mildly viral recently, but I'm not
deflected by that.)

Dear Nick,

Thanks for your help, but I am implementing your solution and it only keep the information for the
year in which subsidy==1. I also need the information for the rest of the years. In the example,
the data corresponding to firm 1 for the years 2001, 2002, 2003 and 2004.

id year subsidy

 1 2000   0
 1 2001   0
 1 2002   1
 1 2003   0
 1 2004   0
 1 2005   1
 2 2000   0
 2 2001   0
 2 2002   1
 2 2003   1
 2 2004   0
 2 2005   1
 3 2000   1
 3 2001   1
 3 2002   1

Sergio

P.S. I will take note of your observation about panel data.