On l�rdag, des 7, 2002, at 11:57 America/Montreal, Sophie Barthel wrote:
One question regarding the running code: will that only count progid
when it takes on the value 0 as that is what I need?
I may have misunderstood and used 1 as the exciting case.
The idea is that bys: sorts the data and constructs the variable np
that counts the observations _within_ progid. Assume there are 241 with
progid==0 and 258 with progid==1. The dataset after the "bys..." line
looks something like this:
progid np
0 1
0 2
...
0 241
1 1
1 2
1 258
Now you construct a variable from these two variables. If you want all
the first 200 with progid==0 to take on the value of 0, and else 1, I
would do
gen byte y = 1 - (progid==0 & np<=200)
The () part is 1 if the argument is true, else it is zero. So y will be
1 if either progid==1 or np>200 and 0 otherwise. Which seems to be what
you want.
entries has exceeded 200, y will take the value 0?
basically my next step would then be to say
stset progtm, failure(y)
This may not work well with my solution: You have to be very careful
about the sort order. I would make sure that you do sort appropriately.
. sort progtm
. gen byte progid0= (progid==0) * is equal to 1 if true
. gen long np0 = sum(progid0) * is the #observation of progid==0
. gen y = 1 - (progid==0 & np0<=200)
. drop np0 progid0
Then you are sure that the first 200 as they appear in time are marked
with 0. If all of this has to be made true for every person, say, with
identification variable pid, the sort has to be sort pid progtm and the
generation of np0 has to be "by pid: gen np0=sum(progid0)". Everything
else should work.
Erik
--
Erik �. S�rensen, <http://www.geocities.com/erik_oiolf/>.
phd student (economics), Norwegian School of Economics.
currently visiting Queen's University, Kingston, Ontario.
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