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Re: st: Using weights from the Current Population survey
At 12:18 PM 7/3/2002 -0500, Nammi Kandula wrote:
My experience is that all weights in surveys from the U.S. Census Bureau
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?
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.
Institute for Policy Studies
Johns Hopkins University
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