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Re: st: Person-period dataset, stcox, subjects in analysis


From   MAY BAYDOUN <mbaydoun2002@yahoo.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Person-period dataset, stcox, subjects in analysis
Date   Sun, 17 May 2009 21:20:46 -0700 (PDT)

Thanks a lot! I will keep that in mind,

Best wishes,

May


--- On Sun, 5/17/09, Jeph Herrin <junk@spandrel.net> wrote:

> From: Jeph Herrin <junk@spandrel.net>
> Subject: Re: st: Person-period dataset, stcox, subjects in analysis
> To: statalist@hsphsun2.harvard.edu
> Date: Sunday, May 17, 2009, 9:53 PM
> After the regression, you want to
> select
> 
>   keep if e(sample)
> 
> hth,
> Jeph
> 
> MAY BAYDOUN wrote:
> > Dear Statalisters,
> > 
> > This may be a straightforward question with an obvious
> answer, but I need your help on it. I have a person-period
> dataset and I used stset command specifying origin and id as
> well as failure and exit. This gave me a specific number of
> failures and number of subjects at risk. I ran stcox using a
> variable that has missing values for a number of those
> subjects. I am trying obtain a selection variable so I can
> look at baseline characteristics of those subjects that were
> selected for this analysis. Which of the variables that were
> generated through the stset command should I be using for
> this purpose? 
> > 
> >  stcox x
> > 
> >          failure _d: 
> failuredem == 2
> >    analysis time _t: 
> (age50dem-origin)
> >             
> origin:  time origin==1
> >   enter on or after:  time
> origin2==1
> >   exit on or before: 
> failuredem==1
> >               
>   id:  id
> > 
> > Iteration 0:   log likelihood =
> -1697.8111
> > Iteration 1:   log likelihood =
> -1696.3502
> > Iteration 2:   log likelihood =
> -1696.3477
> > Refining estimates:
> > Iteration 0:   log likelihood =
> -1696.3477
> > 
> > Cox regression -- Breslow method for ties
> > 
> > No. of subjects =      2321 
>                
>    Number of obs   = 
>    15721
> > No. of failures =      270
> > Time at risk    =  52641.86847
> >               
>                
>                
>     LR chi2(1)      =   
>   2.93
> > Log likelihood 
> =   -1696.3477       
>              Prob
> > chi2     =    0.0871
> > 
> >
> ------------------------------------------------------------------------------
> >           _t | Haz.
> Ratio   Std. Err.      z 
>   P>|z|     [95% Conf.
> Interval]
> >
> -------------+----------------------------------------------------------------
> >         
> x|   1.247601    .159471 
>    1.73   0.084 
>    .9711212   1.602796
> >
> ------------------------------------------------------------------------------
> > 
> > So, basically, I want to be able to describe the 2,321
> subjects in that analysis. I did that before, but I can't
> remember how anymore. Thanks for any help you can provide,
> > 
> > 
> > Sincerely,
> > 
> > May
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> >       *
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> > 
> *
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> 


      

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