Nada,
As far as I understand, you need:
by id,s: replace breast=0 if control ==1 & breast ==.
by id,s: replace colon=0 if control ==1 & colon ==.
by id,s: replace prostate=0 if control ==1 & prostate ==.
Hope it helps,
Vladimir
On Wed, May 28, 2008 at 3:16 PM, Nada Khan <[email protected]> wrote:
> Hi,
>
> I'm having trouble putting my finger on the solution to what may be a simple problem.
>
> I have a matched case control dataset with patients who have had breast, colon or prostate cancer with 4 matched controls each and a matching variable (groupid). My data looks like this:
>
> id groupid breast colon prostate control
> 1 1 1 . . .
> 2 1 . . . 1
> 3 1 . . . 1
> 4 1 . . . 1
> .
> .
> .
> 89 40 . 1 . .
> 90 40 . . . 1
> 91 40 . . . 1
> etc
>
> What I'm trying to do is replace breast = 0 for each control, or colon= 0 for each control, so that my data would look like this:
>
> id groupid breast colon prostate control
> 1 1 1 . . .
> 2 1 0 . . 1
> 3 1 0 . . 1
> 4 1 0 . . 1
> .
> .
> .
> 89 40 . 1 . .
> 90 40 . 0 . 1
> 91 40 . 0 . 1
> etc
>
> I can't seem to get the right combination of gen/replace/bys commands. Can anyone help?
>
> Thanks!
> Nada
>
>
>
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