Date: Wed, 1 Jul 2009 10:06:08 -0700
Reply-To: "Nordlund, Dan (DSHS/RDA)" <NordlDJ@DSHS.WA.GOV>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: "Nordlund, Dan (DSHS/RDA)" <NordlDJ@DSHS.WA.GOV>
Subject: Re: Using SURVEYSELECT for random assignment?
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> -----Original Message-----
> From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of Joe
> Sent: Wednesday, July 01, 2009 9:35 AM
> To: SAS-L@LISTSERV.UGA.EDU
> Subject: Re: Using SURVEYSELECT for random assignment?
> Maybe i'm missing something, but I don't see how that would cause the
> possibility of two people with consecutive (but different) pts_over_50 to be
> switched in order?
> On Wed, Jul 1, 2009 at 11:08 AM, Nordlund, Dan (DSHS/RDA) <
> NordlDJ@dshs.wa.gov> wrote:
> > > -----Original Message-----
> > > From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of
> > > Matise
> > > Sent: Tuesday, June 30, 2009 8:50 PM
> > > To: SAS-L@LISTSERV.UGA.EDU
> > > Subject: Re: Using SURVEYSELECT for random assignment?
> > >
> > > If it were me, with my account groups, I'd not use PROC SURVEYSELECT
> > > directly for this, because of rule 4. I am not a PROC SURVEYSELECT
> > expert,
> > > but reading over the sampling methods, none of them do what that
> > requests.
> > > Specifically, SYS takes every other observation, exactly; not one from
> > each
> > > pair randomly. It might work perfectly fine for what you want, but I
> > don't
> > > think it is precisely what 4. calls for.
> > Couldn't one solve this problem by adding a uniform random number to the
> > dataset, adding the random variable to the end of the BY statement in proc
> > sort, and then use SURVEYSELECT
> > Hope this is helpful,
You haven't missed anything. In my cursory read of the specification, I failed to appreciate that "patients over 50" was effectively a continuous variable (few to no ties) and therefore my suggestion will not work
Daniel J. Nordlund
Washington State Department of Social and Health Services
Planning, Performance, and Accountability
Research and Data Analysis Division
Olympia, WA 98504-5204