LISTSERV at the University of Georgia
Menubar Imagemap
Home Browse Manage Request Manuals Register
Previous (more recent) messageNext (less recent) messagePrevious (more recent) in topicNext (less recent) in topicPrevious (more recent) by same authorNext (less recent) by same authorPrevious page (February 2004, week 4)Back to main SAS-L pageJoin or leave SAS-L (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Tue, 24 Feb 2004 11:55:04 -0800
Reply-To:     Dale McLerran <stringplayer_2@YAHOO.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Dale McLerran <stringplayer_2@YAHOO.COM>
Comments: To: Laura Stapleton <laura.stapleton@MAIL.UTEXAS.EDU>
In-Reply-To:  <>
Content-Type: text/plain; charset=us-ascii


I don't know if SURVEYSELECT can generate the second stage sample that you need. However, there is a simple workaround that you can employ using two datasteps and a proc sort. In the first datastep, attach a random number to your data. Sort the data by PSUID and random number. Finally, set the data by PSUID and keep a counter of the number of observations seen in that PSUID. If the observations number within PSUID is <=10, then output the record.

%let seed=....; data samp_stg1; retain seed &seed; set samp_stg1; call ranuni(seed,x); drop seed; run;

proc sort data=samp_stg1; by psuid x; run;

data samp_stg2; set samp_stg1; by psuid; if first.psuid then nrec_psu=0; nrec_psu+1; if nrec_psu<=10 then output; drop x nrec_psu; run;


--- Laura Stapleton <laura.stapleton@MAIL.UTEXAS.EDU> wrote: > Colleagues- > > I have a possibly basic issue that I cannot solve on my own and would > be > glad for any suggestions. > > I would like to pull a 2-stage sample with PPS of PSUs and then > disproportionate sampling across two strata within each PSU, > resulting in > about 20 units within each PSU. > > My plan was to undertake a PROC SURVEYSELECT using PPS on the PSU > IDs, then > merge back with the full dataset on PSU ID (only retaining IDs in the > selected PSUs). > > Then, undertake a second PROC SURVEYSELECT using SRS with > STRATA = PSUID UNIT_TYPE; > and specifying SAMPSIZE = 10. (I would like about half of the units > to be > from each of the two strata -- in the population they are split > 70%/30%). > > All was working fine until some of my selected PSUs contained fewer > than 10 > units of UNIT_TYPE=2; > When this occurred, the procedure stopped and indicated: > > ERROR: The sample size, 10, is larger than the number of sampling > units, 9. > > Is there some way to inform the procedure to select all (no matter > the > size) if the number of sampling units is less than the sample size? > > If not, does anyone have any ideas to work around this? > > Thank you! > > Laura > > > Laura M. Stapleton > Assistant Professor, Quantitative Methods > Educational Psychology > University of Texas at Austin > 504 SZB > Austin, TX 78712-1296 > phone: 512/471-0858 > fax: 512/471-1288

===== --------------------------------------- Dale McLerran Fred Hutchinson Cancer Research Center mailto: Ph: (206) 667-2926 Fax: (206) 667-5977 ---------------------------------------

__________________________________ Do you Yahoo!? Yahoo! Mail SpamGuard - Read only the mail you want.

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