Pearson correlation coefficient in R's survey package

Question

Sorry if this is really obvious, but I can't see how to do a simple Pearson correlation between two variables in the survey package. My data has strata so it would be the equivalent to finding r for api00 and api99 in apistrat.

library(survey)
data(api)

dstrat <- svydesign(id=~1,strata=~stype, weights=~pw, data=apistrat, fpc=~fpc)

I'm sure there must be a simple way of doing it using svyvar or svyglm or something but I can't see it?

Answer 1

You can use svyvar to estimate the variance-covariance matrix, and then scale it to the correlation:

library(survey)
data(api)

dstrat <- svydesign(id=~1,strata=~stype, weights=~pw, data=apistrat, fpc=~fpc)
v <- svyvar(~api00+api99, dstrat)

as.matrix(v)
cov2cor(as.matrix(v))

This works for any number of correlations and any design.

Answer 2

library(survey)
data(api)
dstrat<-svydesign(id=~1,strata=~stype, weights=~pw, data=apistrat, fpc=~fpc)
summary(svyglm(api00~ell+meals+mobility, design=dstrat),correlation=T)