Date:         Mon, 13 Aug 2007 11:32:40 -0400
Reply-To:     Richard Ristow <wrristow@mindspring.com>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Richard Ristow <wrristow@mindspring.com>
Subject:      Re: Data Management and Multiple Record Same ID
Comments: To: Björn  Türoque
          <donald.asay82@gmail.com>
In-Reply-To:  <2c55fecd0708091419w61ef3fcfy79d1d051551b4fc1@mail.gmail.co m>
Content-Type: text/plain; charset="iso-8859-1"; format=flowed

At 05:19 PM 8/9/2007, Björn Türoque wrote:

>I have a student dataset that has one record for
>each individual course enrollment. I would like
>to compute whether or not someone has enrolled
>in a course prior to the one they are currently
>taking. If a student has taken a course at a
>previous date I would like to have a new
>variable set up that indicates if this is not their first enrollment.
>
>I run into a problem with students who enroll in
>multiple courses simultaniously. I would like
>the data to reflect both of the first courses
>with the same start date are the first course
>the student enrolls in, instead of as a previous course.
>
>I have included data below, the variables Ihave
>reflects what I have been able to compute, and
>the variable Iwant is what I would ideally like to get.

|-----------------------------|---------------------------|
|Output Created               |13-AUG-2007 11:22:26       |
|-----------------------------|---------------------------|
StuID CourseDate CourseNum Ihave Iwant

   111 09/01/2006     357      0     0
   111 09/01/2006     426      1     0
   111 01/01/2007     427      1     1
   111 01/01/2007     595      1     1
   112 01/01/2007     101      0     0
   112 03/04/2007     204      1     1
   113 03/04/2007     101      0     0
   113 03/04/2007     101      1     0
   115 09/01/2006     101      0     0
   115 03/04/2007     357      1     1

Number of cases read:  10    Number of cases listed:  10


*  Try this. SPSS 15 draft output (WRR:not saved separately).

NUMERIC NotFirst (F2).
AGGREGATE OUTFILE=* MODE=ADDVARIABLES
    /BREAK    = StuID
    /FrstDate = MIN(CourseDate).
COMPUTE NotFirst = (CourseDate GT FrstDate).
LIST.

List
|-----------------------------|---------------------------|
|Output Created               |13-AUG-2007 11:27:26       |
|-----------------------------|---------------------------|
StuID CourseDate CourseNum Ihave Iwant NotFirst   FrstDate

   111 09/01/2006     357      0     0      0    09/01/2006
   111 09/01/2006     426      1     0      0    09/01/2006
   111 01/01/2007     427      1     1      1    09/01/2006
   111 01/01/2007     595      1     1      1    09/01/2006
   112 01/01/2007     101      0     0      0    01/01/2007
   112 03/04/2007     204      1     1      1    01/01/2007
   113 03/04/2007     101      0     0      0    03/04/2007
   113 03/04/2007     101      1     0      0    03/04/2007
   115 09/01/2006     101      0     0      0    09/01/2006
   115 03/04/2007     357      1     1      1    09/01/2006

Number of cases read:  10    Number of cases listed:  10
===========================================
APPENDIX: Test data (from original posting)
===========================================
Data List LIST
/ StuID  * CourseDate(ADATE) CourseNum Ihave Iwant.
Begin Data
   111 09/01/06   357 0 0
   111 09/01/06   426 1 0
   111 01/01/07   427 1 1
   111 01/01/07   595 1 1
   112 01/01/07   101 0 0
   112 03/04/07   204 1 1
   113 03/04/07   101 0 0
   113 03/04/07   101 1 0
   115 09/01/06   101 0 0
   115 03/04/07   357 1 1
END DATA.
FORMATS StuID CourseNum (F4)
        /Ihave Iwant     (F2).
LIST.