Re: st: Data management problem

["David W. Harless" <dwharles@vcu.edu>]

n j cox wrote:
> No suggestions from me, just a question.
>
> How you do know that the examples refer to the same individual?
> Are there identifier variable(s) too?
>
> Nick
> n.j.cox@durham.ac.uk
Oh yes, there is an id variable to identify individuals between the two data sets.  I 
guess I should have included that in the message, but I was trying to make the example as 
simple as possible.

Dave Harless


> David W. Harless
>
> I have two data sets containing dates of participation in two related 
> programs, program 1
> and program 2.  But the complication is that the program 1 data set 
> lists dates if the
> participant is enrolled in *either* program 1 or program 2.  Dates in 
> the program 2 data
> set indicate definite participation in program 2.
>
> The best explanation is an example.  Here is program participation dates 
> from the program
> 1 data set.  (Date variables have display format %dD_m_Y and I added the 
> program variable
> to make this explanation clearer):
>
>           beg1        end1   program
>      01 Jul 02   30 Nov 02         1
>      01 Jul 03   30 Jun 05         1
>
> And the same individual for the program 2 data set:
>
>           beg2        end2   program
>      01 Jul 02   30 Nov 02         2
>      01 Oct 03   31 Dec 04         2
>      01 May 05   31 May 05         2
>
>
> I want to combine these records to obtain a data set that looks like:
>
>            beg         end   program
>      01 Jul 02   30 Nov 02         2
>      01 Dec 02   30 Jun 03         0
>      01 Jul 03   30 Sep 03         1
>      01 Oct 03   31 Dec 04         2
>      01 Jan 05   30 Apr 05         1
>      01 May 05   31 May 05         2
>      01 Jun 05   30 Jun 05         1
>
> (where the 0 indicates the individual did not participate in either 
> program during that
> period).
>
> There are, of course, many individuals with varying dates of 
> participation in one or both
> programs.  Any suggestions as to how one might solve this problem?
>
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