LISTSERV at the University of Georgia
Menubar Imagemap
Home Browse Manage Request Manuals Register
Previous messageNext messagePrevious in topicNext in topicPrevious by same authorNext by same authorPrevious page (May 2003)Back to main SPSSX-L pageJoin or leave SPSSX-L (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Mon, 12 May 2003 09:01:52 -0400
Reply-To:     Michael Kruger <m_kruger@WAYNE.EDU>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Michael Kruger <m_kruger@WAYNE.EDU>
Subject:      Help with selecting controls for cases
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I am trying to select 2 controls for each case in a dataset of about 16,000 subjects. The data is structured as follows:

ID BIRTHYR CASE SURVIVAL 1 1915 1 87 2 1915 0 80 3 1915 0 63 4 1915 0 87 6 1915 0 71 7 1925 1 77 8 1925 0 87 9 1925 0 67 10 1925 0 52

I need to pick 2 'controls' (case=0) matched on birhtyr for each of my cases. But for each case there may be over 100 controls in the file, while for some cases (years) there may be only 3 or 4 controls in the file. Many of the cases have the same birth year, but I don't think that should affect the matching process. I want to randomly select 2 controls for each case mathced by 'birhtyr' There are 147 cases in the file and approximately 5400 controls that match the birth years of the cases. I wnat to end up with a sekected data set if 146 cases abd 292 randomly selected but birthyear matched controls.

Any help in writing syntax for this would be appreciated. Thanks. .

-- Michael Kruger Statistical Analyst C.S. Mott Center for Human Growth & Development Dept. of OB/GYN Wayne State Univ. School of Medicine (313)-577-1794

Back to: Top of message | Previous page | Main SPSSX-L page