Re: st: Event within dates

[David Kantor <kantor.d@att.net>]

The following might work. It is an attempt to fill in some features 
that were needed in your method.
But it is somewhat brute-force in its approach. It does looping over 
observations (doubly), which is rarely needed.
There is probably a much better way to do this (involving -by-, for 
one), but this is all I can do at the moment.
HTH
--David


forval i = 1/ `N' {
        forval j = 1/ `N' {
                replace rs1=1 if drug[`i]==1 & id[`i']==id[`j']  & 
inrange(date[`i'] - date[`j'],-56,56) in `i'
        }
}


At 02:15 PM 12/1/2011, David Kpento wrote:
> I have prescription data in panel format for analysis. I wish to 
> generate an indicator rs to be 1 for any subject who took drug2 
> within 56 days of taking drug1 (either before or after). Could 
> somebody please help me with any code? I am new to Stata so have 
> struggled with this for days.
>
>
>
> I use Stata/SE 9.0 for Windows.
>
> Many thanks
>
> David
> clear
> input id str9 date drug rs
> 1 08apr2009 1 0
> 1 08may2009 1 0
> 1 08jun2009 2 1
> 2 02jan2009 1 0
> 2 28jan2009 2 1
> 2 05apr2009 1 0
> 3 07jan2009 2 1
> 3 22mar2009 1 0
> 3 02jul2009 1 0
> end
>
> I have a code like this after formatting the date into a Stata date 
> but rs1 is all zeros.
>
> gen date1 = date(date, "dmy")
> format date1 %d
> drop date
> rename date1 date
>
> g rs1=0
> local N=_N
> forval i = 1/ `N' {
> replace rs1=1 if drug==1 & id[`i'] & inrange(date[`i'] - date,-56,56) in `i'
> }

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