Stata The Stata listserver
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

RE: st: Using weights from the Current Population survey


From   "Kaganova, Yevgeniya M." <YKAGANOVA@PARTNERS.ORG>
To   "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
Subject   RE: st: Using weights from the Current Population survey
Date   Mon, 22 Jul 2002 10:27:55 -0400

> -----Original Message-----
> From:	Lee Sieswerda [SMTP:Lee.Sieswerda@tbdhu.com]
> Sent:	Wednesday, July 03, 2002 2:24 PM
> To:	'statalist@hsphsun2.harvard.edu'
> Subject:	RE: st: Using weights from the Current Population survey
> 
> A better option than using iweight or aweight with -tabulate- is to use
> -svytab- and pweight. It has several advantages, one of which is that gives
> you asymptotic 95% CIs that will not cross 0 or 1 (which is good because you
> can't have less than 0 people enter a survey response, nor more than 100%). 
> 
> And to head off the next question, -svytab- won't allow you to specify only
> one variable in the command statement. If you want to tabulate the responses
> to a single question you have to create a constant (e.g., gen dum=1) and use
> it as your second variable, as in:
> svytab q1 dum, [options - lots of them]
> 
> Also, make sure you use the -subpop- option to specify subpopulations, not
> -if- or -in-.
> 
> And finally, you absolutely have to use the weights provided if you want the
> results to be representative of the population and not just the sample. I
> don't know about the CPS specifically, but it is unlikely that you'll be
> provided with the psu and strata information because in well-conducted
> surveys the clusters sampled are usually quite small and it would be
> possible for a determined analyst to identify individuals - especially in
> lightly-populated areas. To get around this problem in Canada, at least, for
> large government surveys we are provided with a data set of bootstrap
> weights from which to calculate bootstrapped standard errors. If you do not
> have access to the psu and strata information, then you might enquire if
> such a beast is available for the Current Population Survey.
> 
> Best regards,
> 
> Lee S.
> 
> Lee Sieswerda, Epidemiologist
> Thunder Bay District Health Unit
> 999 Balmoral Street
> Thunder Bay, Ontario
> Canada  P7B 6E7
> Tel: +1 (807) 625-5957
> Fax: +1 (807) 623-2369
> Lee.Sieswerda@tbdhu.com
> www.tbdhu.com
> 
> 
> 
> > -----Original Message-----
> > From:	David Kantor [SMTP:dkantor@jhu.edu]
> > Sent:	Wednesday, July 03, 2002 1:53 PM
> > To:	statalist@hsphsun2.harvard.edu
> > Subject:	Re: st: Using weights from the Current Population survey
> > 
> > At 12:18 PM 7/3/2002 -0500, Nammi Kandula wrote:
> > >I am doing an analysis with the MARCH current population survey.
> > >I am doing a person-level analysis.
> > >
> > >If I use the wgt varaible, stata asks me what kind of weight this is.
> > >Is it an analytic weight, pweight, fweight?
> > >
> > >Should I use the weight in my regressions, or in my tab commands. Do i
> > need
> > >to transform the weight in any way?
> > 
> > My experience is that all weights in surveys from the U.S. Census Bureau 
> > are pweights.
> > 
> > You should specify them as pweights in regressions. (If you use them as 
> > aweight, the coefficients will be the same, but the variances and 
> > confidence intervals will be wrong.  See the section in the user guide on 
> > Estimation, Weighted Estimation; that's U 26.12 in my ancient V5 manual.)
> > 
> > Better -- use svyreg and specify the strata and psu, if these are 
> > identified. Still, specify the weight as pweight.
> > 
> > For -tabulate-, pweight is not accepted.  Use aweight or iweight; the 
> > proportions will not be affected by the choice, but iweight has the 
> > advantage that the "Freq." will be the weighted sums of the observations
> > -- 
> > i.e., the estimated number of actual population in the given category.  Be
> > 
> > sure you have scaled the weight correctly at the outset, if there are any 
> > implied decimals in the raw data.
> > 
> > I hope this helps.
> > -- David K.
> > 
> > David Kantor
> > Institute for Policy Studies
> > Johns Hopkins University
> > dkantor@jhu.edu
> > 410-516-5404
> > 
> > *
> > *   For searches and help try:
> > *   http://www.stata.com/support/faqs/res/findit.html
> > *   http://www.stata.com/support/statalist/faq
> > *   http://www.ats.ucla.edu/stat/stata/
> *
> *   For searches and help try:
> *   http://www.stata.com/support/faqs/res/findit.html
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index