You should find out about -by:-.
For example:
bysort MRN (VisitDate) : gen visit = _n
by MRN : gen change = BMI[_N] - BMI[1]
Nick
[email protected]
Karen R. Fl�rez
> I have a dataset with kids BMIs that looks like this:
>
> MRN VisitDate BMI
>
> 123 10/20/04 30
>
> 123 6/11/05 25
>
> 123 4/14/06 25
>
> 222
>
> 222
>
> 222
>
>
>
> Where MRN is the unique identifier. Kids had different visits at
> different times and BMI were take at each time. How can I generate
> a variable that codes for Visit 1,2,3,etc? So that I can measure
> the change between baseline and last follow-up?
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