Another way to do it:
bysort id (year) : gen byte last = _n == _N
local n = _N + 1
expand 2 if last
replace year = year + 1 in `n'/l
drop last
bysort id (year): gen byte died = _n == _N
edit id year died
Nick
[email protected]
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Nick Cox
> Sent: 19 April 2005 17:21
> To: [email protected]
> Subject: st: RE: How to add a records to panel data
>
>
> Comments on three levels:
>
> 1. Don't do this. If you do this, you lock
> yourself into needing to exclude such records from
> most later analyses. Unless memory is a real
> issue, have a variable containing this
> information, i.e. store it in an extra column,
> not extra rows. Even though values are repeated
> for every observation in each panel, that is
> usually not a problem and indeed often helpful.
>
> So to get what you need, without changing
> the number of records,
>
> egen died = max(year), by(id)
> replace died = died + 1
>
> 2. If you don't accept my advice, you need
> something like this:
>
> gen byte died = 0
> egen group = group(id)
> su group, meanonly
> qui forval g = 1/`r(max)' {
> su year if group == `g', meanonly
> expand 2 if group == `g' & year == r(max)
> replace year = r(max) + 1 in l
> replace died = 1 in l
> }
> drop group
> sort id year
> edit id year died
>
> 3. Really, don't do this. See #1.
>
> Nick
> [email protected]
>
> xiao yi
>
> > I have an unbalanced panel data(cross-setion and
> > time-series) which looks like below:
> >
> > ID year x1 x2
> > 1 1993 .. ..
> > 1 1994 .. ..
> > 1 1995 .. ..
> > 2 1995 .. ..
> > 2 1996 .. ..
> > 2 1997 .. ..
> > 3 1993 .. ..
> > 3 1994 .. ..
> > 3 1995 .. ..
> >
> > The data is about firms' survival analysis. The last
> > year of my sample is 2003. In the example above, firm
> > 1 dies in 1996 because the last year of this firm
> > is 1995 and firm 2 dies in 1998, and so on. I want to
> > add a record at the end of each subject (firm)
> > indicating the year when the fird dies. Can anyone
> > tell me how to accomplish this? Thank you in advance.
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