st: RE: When to use stdize and stdweight with svy: tab and svy: mean?

["Scholes, Shaun" <s.scholes@ucl.ac.uk>]

Hi Arturo, I think the short answer is that the stdize and stdweight options are only needed if you are interested in direct standardisation. If not, then svy:tab dummy district will be sufficient for your purposes.

i) Your variable health_center is the sampling strata (and so is declared in the svyset command) - as is the sampling weight (pw).
ii) You may (as I often do) want to adjust the sampling weight to ensure the same age distribution across groups. This would make age the standard strata; and stdweight would be a variable (call it varX) that would contain the population sizes in each age group.

So then you would use:

svy: tab dummy district, stdize(age) stdweight(varX)

Hope this helps
Shaun













-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Arturo Rodriguez
Sent: 17 November 2011 23:05
To: statalist@hsphsun2.harvard.edu
Subject: st: When to use stdize and stdweight with svy: tab and svy: mean?

Hi everybody,

I am working with survey data which was collected through a one-stage cluster sample with stratification. I am trying to tabulate two variables -a dummy and a categorical variable identifying districts. I noticed that I can do the tabulation either by using "svy: tab dummy district" or by "svy: tab dummy district, sdize(strata_var) stdweight(weight_var)". I ran both commands and see that the % in the results change from one command to the other; however, I don't know what is happening behind the scenes.

My sample was stratified (by health centers) and the primary sampling unit were "villages". In defining my survey characteristics I used the
command:
svyset villages [pweight = pw] strata(health_center)
fpc(total_number_of_villages_per_hc)

What is the difference between the results I'm getting from each option?
(1) svy: tab dummy district
(2) svy: tab dummy district, stdize(health_centre) stdweight(pw)

Since I'm working with stratified cluster data, does that necessarily mean that all my svy: tab and svy: mean commands need to specify the stdize and stdweight options?

Thanks in advance for all the wisdom.

Arturo
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