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From |
Scott Cunningham <scunning@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: RE: question |

Date |
Thu, 3 Nov 2005 06:47:26 -0500 |

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?* * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

* * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**st: RE: question***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

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