Date:         Tue, 26 Feb 2002 16:48:57 -0500
Reply-To:     Ian Whitlock <WHITLOI1@WESTAT.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Ian Whitlock <WHITLOI1@WESTAT.COM>
Subject:      Re: Version of Case Control Program
Comments: To: "JGerstle@SW.UA.EDU" <JGerstle@SW.UA.EDU>
Content-Type: text/plain; charset="iso-8859-1"

John,

Here is example sampling code.  In my case two males do not have
correspondent females.  They are in the file PROB.  The random matches are
in file W.  The example is curious because it is one of the few examples
that I know of where one wants to do a one-to-one merge within by group
legitimately.

The message

NOTE: MERGE statement has more than one data set with repeats of BY values.

is most likely and has been accounted for in the code.

data males ;
   do id = 1 to 20 ;
      agegrp = ceil ( 10 * ranuni ( 67493 ) ) ;
      salgrp = ceil ( 10 * ranuni ( 67493 ) ) ;
      output ;
   end ;
run ;

data females ;
   do id = 100 to 299 ;
      agegrp = ceil ( 10 * ranuni ( 617493 ) ) ;
      salgrp = ceil ( 10 * ranuni ( 617493 ) ) ;
      output ;
   end ;
run ;

data females ;
   set females ;
   random = ranuni ( 961743 ) ;
run ;

proc sort data = males ;
   by agegrp salgrp ;
run ;

proc sort data = females ;
   by agegrp salgrp random ;
run ;

data w prob ;
  w = 0 ; f = 0 ;
  merge males ( in = w )
        females ( in = f rename = id = fid )
  ;
  by agegrp salgrp ;
  if w and f then output w ;
  else
  if w then output prob ;
run ;

IanWhitlock@westat.com

-----Original Message-----
From: John Gerstle [mailto:JGerstle@SW.UA.EDU]
Sent: Tuesday, February 26, 2002 2:48 PM
To: SAS-L@LISTSERV.UGA.EDU
Subject: Version of Case Control Program


SAS-Lers,
        I'm looking for some sample Case Control code.
        Presently, I have a dataset where I would like to match the 20
males with 20 females that match them along some parameters
out of a total of 200 females.  In other words, I would like to run
some simple analyses based on gender, but only have 20 males
versus 200 females.  And let's say, that the parameters I would like
to use are age (in five year increments) and income level (in $20K
increments).
        So for every male, there is some subset of females that match
in terms of age level and income level, and I would like to randomly
select one of these females to 'pair' with the males.  In this way,
the two genders will be matched on age and income.
        I have been successful in manually creating matches (printing
out the data, highlighting matches, hard coding ids to pull, etc...).
But I would like to have something that would generalize over to a
larger dataset with many more levels (say, 100 males and 2000
females).
        Does anyone have something that would do this?  (I haven't
checked SCONSIG or the SAS site yet...thought I'd question the
List first in case others out there might need something similar.)

        Thanks, John


John Gerstle, M.S.
Program Analyst, Sr.
Applied Gerontology Program
University of Alabama