Re: st: calculating cumulative exposure

[Enzo Coviello <enzo.coviello@alice.it>]

At 16.36 03/08/2007, you wrote:
> Dear statalisters,
>
> I�ve got multiple records per person and want to 
> calculate some kind of cumulative exposure index 
> per person. I�ve got a variable called 
> �exposure� and want to create a new variable 
> called �cum_exposure�. Each observation in the 
> cum_exposure variable should give the sum of all 
> previous cells in the exposure column (but per 
> person). So something like this:
>
> Id      Exposure        list            Cum.Exposure
> 1       10              1                       10
> 1       14              2                       24
> 1       15              3                       39
> 2       8               1                       8
> 2       10              2                       18
> 2       15              3                       32

Try:

bysort Id: g cumexp=sum(Exposure)


Enzo

Enzo Coviello
Unit� di Epidemiologia e Statitica ASL BARI
Piazza V.  Emanuele 14 - 70054 Giovinazzo (Bari)
tel./fax 080 3357867
mobile 347 5016 016 

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