Re: st: RE: question

[Scott Cunningham <scunning@gmail.com>]

Thank you - that is the relevant FAQ for my question.  Sorry about  
that title, too.  I didn't even notice that I'd put that until after  
it showed up on the listserv.

On Nov 3, 2005, at 6:38 AM, Nick Cox wrote:


> First, note that the title "question" is not informative.
>
> You have two questions. On the second, there is an FAQ
>
> FAQ     . . . . . . . . . . . . . . . . . . . . . . . Replacing  
> missing values
>         2/03    How can I replace missing values with previous or
>                 following nonmissing values?
>                 http://www.stata.com/support/faqs/data/missing.html
>
> . search missing
>
> points to this.
>
> On the first, I am no survival expert,
> but absent a view of all your data your question looks very
> difficult to answer. But you can at a minimum compare the results on
> non-missing data and on data including imputations to see
> what difference it makes.
>
> Nick
> n.j.cox@durham.ac.uk
>
> Scott Cunningham
>
>
>
> > I am estimating a hazard, but I am missing data for certain time-
> > variant covariates when t is very small.  Seeing data will help me
> > explain this.
> >
> > +--------------------------------+
> >       |       sr   _st   _d   _t   _t0 |
> >       |--------------------------------|
> >    1. |        .     1    0    1     0 |
> >    2. |        .     1    0    2     1 |
> >    3. |        .     1    0    3     2 |
> >    4. |        .     1    0    4     3 |
> >    5. |        .     1    0    5     4 |
> >       |--------------------------------|
> >    6. |        .     1    0    6     5 |
> >    7. |        .     1    0    7     6 |
> >    8. |        .     1    0    8     7 |
> >    9. |        .     1    0    9     8 |
> > 10. | .9738716     1    0   10     9 |
> >       |--------------------------------|
> > 11. | 1.081043     1    0   11    10 |
> > 12. |  1.21261     1    0   12    11 |
> > 13. | 1.125889     1    1   13    12 |
> > 14. |        .     1    0    1     0 |
> > 15. |        .     1    0    2     1 |
> >       |--------------------------------|
> > 16. |        .     1    0    3     2 |
> > 17. |        .     1    0    4     3 |
> > 18. |        .     1    0    5     4 |
> > 19. |        .     1    0    6     5 |
> > 20. |        .     1    0    7     6 |
> >       |--------------------------------|
> > 21. |        .     1    0    8     7 |
> > 22. |        .     1    0    9     8 |
> > 23. | .9738716     1    0   10     9 |
> > 24. | 1.081043     1    0   11    10 |
> > 25. |  1.21261     1    0   12    11 |
> >       |--------------------------------|
> > 26. | 1.125889     1    0   13    12 |
> > 27. | 1.080463     1    0   14    13 |
> > 28. | .9527455     1    1   15    14 |
> >
> >
> > Notice that for all values of t=0 to t=9, I am missing data for sr.
> > My first question is when I -streg-, what effect does this
> > have on my
> > estimation?  None of my respondents complete their respective spells
> > prior to t=10.  Secondly, assume I wanted to fill in those missing
> > values with the same value as t=10.  How would I do this?
> *
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*
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