Whether your data require simple weighted adjustment because
of differential sampling rates or you have data from a
complex multistage survey, Stata's survey features can provide
you with correct standard errors and confidence intervals for
your inferences. All you need to do is specify the relevant
characteristics of your sampling design, including sampling
weights (including weights at multiple stages), clustering (at
one, two, or more stages), stratification, and poststratificaion.
After that, most of Stata's estimation commands can adjust
their estimates to correct for your sampling design.