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st: RE: How to generate id numbers when expanding data


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: How to generate id numbers when expanding data
Date   Sun, 15 Oct 2006 17:43:33 +0100

I am not sure that I understand this

egen id = seq(), block(3) 

may help. 

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

Dick Campbell
 
> For teaching purposes I have created a table of results from 
> an imaginary 
> experiment as shown below.
> 
> 
>       +----------------------------------+
>       | wave   cond   sex    n   outcome |
>       |----------------------------------|
>    1. |    1      1     1   25        50 |
>    2. |    2      1     1   18        49 |
>    3. |    3      1     1   15        51 |
>    4. |    1      2     1   25        50 |
>    5. |    2      2     1   20        55 |
>       |----------------------------------|
>    6. |    3      2     1   19        54 |
>    7. |    1      3     1   25        50 |
>    8. |    2      3     1   16        58 |
>    9. |    3      3     1   14        53 |
>   10. |    1      1     2   25        50 |
>       |----------------------------------|
>   11. |    2      1     2   19        51 |
>   12. |    3      1     2   17        50 |
>   13. |    1      2     2   25        50 |
>   14. |    2      2     2   21        57 |
>   15. |    3      2     2   20        56 |
>       |----------------------------------|
>   16. |    1      3     2   25        50 |
>   17. |    2      3     2   17        56 |
>   18. |    3      3     2   15        54 |
>       +----------------------------------+
> 
> The variable labeled "outcome" is a cell mean and I will 
> expand the table 
> by n cases for each cell.
>   I will subsequently manipulate these data by adding random 
> error to the 
> outcome variable ,
> adding covariates etc.
> 
> However, when I eventually analyze the data I need a unique 
> id number for 
> each case such that each record has an id
> number which stays constant across waves so that I can use 
> XT-series routines.
> So, the expanded data set should look like this.
> 
> 
>       +----------------------------------+
>       |id wave   cond   sex      outcome |
>       |----------------------------------|
>    1. |1   1      1     1             50 |
>    2. |1   2      1     1             49 |
>    3. |1   3      1     1             51 |
>    4. |2   1      1     1             50 |
>    5. |2   2      1     1             55 |
>       |----------------------------------|
>    6. |2   3      1     1             54 |
>    7. |3   1      1     1             50 |
>    8. |3   2      1     1             58 |
>    9. |3   3      1     1             53 |
>   10. |4   1      1     1             50 |
>       |----------------------------------|
>   11. |4   2      1     1             51 |
>   12. |4   3      1     1             50 |
>   13. |5   1      1     1             50 |
>   14. |5   2      1     1             57 |
>   15. |5   3      1     1             56 |
>       |----------------------------------|
>   16. |6   1      1     1             50 |
>   17. |6   2      1     1             56 |
>   18. |6   3      1     1             54 |
> 
> etc through the 361 records implied by the data. Within
> each combination of sex and cond there should be n cases
> with an id that stays constant across waves.
> 
> I can not seem to figure out how to do this. I would guess that
> -expandcl- should accomplish what I want, but I can't figure out
> how to set it up. Perhaps there is some other clever solution.
> If I were in SAS I would just loop over n with an -output- statement
> and retain the counter as an ID. But I am a bit stymied here.
> 
> 
> Dick Campbell
> Univ. of Illinois at Chicago
> 
>    
> 
> 
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