Mar�a Elena Casquel del Campo <[email protected]> asks:
> I�m trying to estimate duration models with Stata. The problem is that I
> have multispell data in the sense that some individuals experiment failures
> but later enter another time in the sample. I�d like that when the
> individual enters after experimenting failure the clock starts clicking
> another time.
> I have introduced:
> stset finish, failure(cens) time0(star) exit(time .) id(pid) origin(star)
> pid wave _t0 _t _d
> 120. 130911101 1 0 11 1
> 121. 130911101 2 12 23 0
> 122. 130911101 3 24 35 0
> 123. 151701103 1 0 11 1
> 124. 151701103 2 12 23 0
> 125. 151701103 3 24 35 0
> 126. 151701103 4 36 47 0
> 127. 151701103 5 48 59 0
> 128. 213341102 1 0 11 1
> 129. 213341102 2 12 23 0
> 130. 213341102 3 24 35 1
> I would like that _t0 start in 0 for the individual 130911101, observation
> 121.
There is some discussion of how to do this in [R] stsum. Try,
. stgen nf = nfailures()
. egen newpid = group(pid nf)
. sort newpid finish
. by newpid: gen newstar = star - star[1]
. stset finish, failure(cens) id(newpid) time0(newstar)
Also note: If you plan on fitting any regression to these models, be sure to
specify -cluster(pid)- since one would usually not consider the multiple
failures of each subject as independent events.
--Bobby
[email protected]
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