st: question

[Scott Cunningham <scunning@gmail.com>]

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?

sc
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