Date:         Mon, 28 Jun 2004 15:53:25 -0400
Reply-To:     "Whitt, Susanne" <SWhitt@hq.odedodea.edu>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         "Whitt, Susanne" <SWhitt@hq.odedodea.edu>
Subject:      Re: assign a unique ID number

I always use the UNIFORM or RV.UNIFORM function in addition to creating
$casenum, because one can never be certain that there isn't some underlying
systematic bias to the order of the cases.  For example, if cases are
entered as they arrive:  is there something different about early responders
than late responders?  To make sure there is no possible bias, I create a
variable using UNIFORM or RV.UNIFORM, sort by it, then compute an ID using
$casenum.  Some would say it's overkill, but it works for me, and besides
it's so easy, why not?

COMPUTE order1 = UNIFORM(111).
EXECUTE.
SORT CASES BY
  order1 (A).
COMPUTE id1 = $casenum.
EXECUTE.

OR . . . .

COMPUTE order2 = RV.UNIFORM(1,111).
EXECUTE.
SORT CASES BY
  order2 (A).
COMPUTE id2 = $casenum.
EXECUTE.

Susanne Whitt, Ph.D.
Research & Evaluation Specialist
Dept. of Defense Education Activity
4040 N. Fairfax Drive
Arlington, VA  22203
(703) 588-3162
(703) 588-3702 (FAX)
swhitt@hq.odedodea.edu

-----Original Message-----
From: Hector Maletta [mailto:hmaletta@fibertel.com.ar]
Sent: Monday, June 28, 2004 3:12 PM
To: SPSSX-L@LISTSERV.UGA.EDU
Subject: Re: assign a unique ID number

I was not clear either that the UNIFORM command was still desired. In fact,
it is not necessary at all. $CASENUM gives a unique number to each case, and
this is all that was originally needed. Since $CASENUM has unique values,
the assignment of an ID based on $CASENUM can be done with unsorted cases.
Later, if desired, cases can be sorted by the new ID variable.
Hector

> -----Original Message-----
> From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU]
> On Behalf Of Hetter, Rebecca D,,DMDCWEST
> Sent: Monday, June 28, 2004 3:48 PM
> To: SPSSX-L@LISTSERV.UGA.EDU
> Subject: Re: assign a unique ID number
>
>
> I guess I wasn't clear enough when I wrote adding the two
> statements. I meant following the call to the UNIFORM
> function. However, if SORT CASES is not used (after the call
> to UNIFORM), the cases will remain in the original order,
> which is not random.
>
> HTH
>
> -----Original Message-----
> From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU]
> On Behalf Of Hector Maletta
> Sent: Monday, June 28, 2004 11:28 AM
> To: SPSSX-L@LISTSERV.UGA.EDU
> Subject: Re: assign a unique ID number
>
>
> The SORT CASES command is not required, and furthermore, it
> is not possible to sort by BRAINNO before creating that
> variable. Hector
>
> > -----Original Message-----
> > From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU]
> On Behalf
> > Of Hetter, Rebecca D,,DMDCWEST
> > Sent: Monday, June 28, 2004 3:14 PM
> > To: SPSSX-L@LISTSERV.UGA.EDU
> > Subject: Re: assign a unique ID number
> >
> >
> > The assignments you obtained were random - that's why it's
> possible to
> > have duplicates.  The system variable $casenum qives the sequence
> > numbers of the records within the file, and those are
> unique.  Try it
> > adding these
> > statements:
> >
> > sort cases by brainno.
> > compute brainno=$casenum.
> >
> > HTH
> >
> >
> > -----Original Message-----
> > From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU]
> On Behalf
> > Of Jodene Goldenring Fine
> > Sent: Sunday, June 27, 2004 8:40 AM
> > To: SPSSX-L@LISTSERV.UGA.EDU
> > Subject: assign a unique ID number
> >
> >
> > Hello Listservers!
> >
> > I have a simple problem that I just can't seem to get
> around. I have
> > 111 cases to which I would like to assign unique ID numbers from
> > 1-111. This is so I can be "blind" to the data I'm working with. I
> > tried the following
> > syntax:
> >
> > numeric brainno (F8.0).
> > compute brainno=rv.uniform(1,111).
> >
> > but the assignments were not random. So, I ended up with 3 cases
> > assigned 44 and 2 cases assigned 12, etc. How can I do this?
> >
> > Thanks for the help!
> >
> > Jodene
> >
> >
> >
> > __________________________________
> >
> > Jodene Goldenring Fine, M.S., N.C.S.P.
> > Doctoral Candidate
> > The University of Texas at Austin
> > Department of Educational Psychology
> >
> > jodene.fine@mail.utexas.edu
> > ________________________________
> >
> > "Be a nice person and see if it works."
> > Chinese Fortune Cookie, Berkeley, California, circa 1974
> >
>