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st: RE: stset problem, please help


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: stset problem, please help
Date   Tue, 3 May 2005 23:20:04 +0100

may be what you need here. The Statalist FAQ (URL 
below) points to the Stata FAQs as one source of help. 

Nick 
n.j.cox@durham.ac.uk 

Saubhik
 
> I'm having some problem in stset-ing my panel data covering 
> period from 1975 to
> 1999. This is how my data looks like:
> 
> Id	year	spell duration	censor	 x
> 1	1975	1	2	0	-0.67
> 1	1976	1		0	4.55
> 1	1977	0		0	2.68
> 1	1978	0		0	2.43
> 1	1979	0		0	3.23
> 1	1980	0		0	2.13
> 1	1981	1	2	0	-0.12
> 1	1982	1		0	-1.76
> 1	1983	0		0	0.34
> 1	1984	0		0	2.6
> 1	1985	0		0	2.58
> 1	1986	0		0	2.17
> 1	1987	0		0	2.54
> 1	1988	0		0	2.32
> 1	1989	0		0	2.29
> 1	1990	0		0	0.88
> 1	1991	0		0	1.32
> 1	1992	0		0	1.34
> 1	1993	0		0	1.66
> 1	1994	0		0	3.27
> 1	1995	0		0	2.52
> 1	1996	0		0	2.4
> 1	1997	0		0	2.72
> 1	1998	0		0	1.9
> 1	1999	0		0	-999
> 46	1975	0		0	0.5
> 46	1976	0		0	5.29
> 46	1977	0		0	2.1
> 46	1978	0		0	2.27
> 46	1979	0		0	2.53
> 46	1980	0		0	0.57
> 46	1981	1	4	0	-0.28
> 46	1982	1		0	-1.84
> 46	1983	1		0	1.1
> 46	1984	1		0	1.26
> 46	1985	0		0	0.19
> 46	1986	0		0	-0.49
> 46	1987	0		0	2.58
> 46	1988	0		0	3.6
> 46	1989	0		0	3.3
> 46	1990	0		0	2.2
> 46	1991	0		0	-0.17
> 46	1992	0		0	0.42
> 46	1993	0		0	0.41
> 46	1994	0		0	2.16
> 46	1995	0		0	3.9
> 46	1996	0		0	2.7
> 46	1997	1	3	1	1.62
> 46	1998	1		0	0.47
> 46	1999	1		0	-999
> 
> 
> 
> My failure variable is 'spell'. Failure occurs when spell = 0. And the
> subject is at the risk of failure when spell=1. I'm interested in the
> transition from spell=1 to spell=0. Consequently, once a 
> failure occurs all the
> subsequent failures are irrelevant until the subject is at risk again.
> 
> so when I specify the 'origin(spell==1)' , that command sets 
> the first observed
> spell=1 for that subject as origin. But ideally, that origin 
> should change when
> the same subject comes under the risk of failure again.
> 
> Another important thing is the duration of the risk of 
> failure. For example, in
> my first observation, in 1975 and 1976 the subject is under 
> the risk of failure
> and the failure is observed in 1977. So the duration of spell 
> is 2 years and I
> want stata to record the 'x' value corresponding to 1975. But 
> from the -st
> variable, I can see that stata is dropping that observation 
> and retaining
> observation after 1976 which is irrelevant.
> 
> And the '_d' variable is also surprising. It is supposed to 
> denote the censored
> observations. But many a times _d=1 when the observation is 
> not censored. In my
> data, censoring is an exogenous information which is captured 
> by the variable
> 'censor'. When censor=1, then only that particular spell is censored.
> 
> 
> I gave the following command:
> 
> stset year, id(cid) failure(spell==0) exit(year==1999) 
> origin(spell==1) scale(1)
> 
> And I know that I'm doing it wrong. I tried the snapspan 
> command as well. Is
> there anyway, I can fix this problem.
> 

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