"Survey" package and NAMCS data... unsure of specification
On Tue, 4 Oct 2005, David L. Van Brunt, Ph.D. wrote:
Hello, all. I wanted to use the "survey" package to analyze data from the National Ambulatory Medical Care Survey, and am having some difficulty translating the analysis keywords from one package (Stata) to the other (R). The data were collected using a multistage probability sampling, and there are variables included to identify the sampling units and weights. Documentation from the NAMCS describes this for Stata as follows (note the variable names in the data are in caps): The pweight (PATWT), strata (CSTRATM), and PSU (CPSUM) are set with the svyset command as follows: svyset pweight PATWT svyset strata CSTRATM svyset psu CPSUM
Supposing your data frame is called 'namcs'
dnamcs <- svydesign(id=~CPSUM, strata=~CSTRATM, weight=~PATWT, data=namcs)
or perhaps
dnamcs <- svydesign(id=~CPSUM, strata=~CSTRATM, weight=~PATWT,
data=namcs, nest=TRUE)
(nest=TRUE is needed if CPSUM repeats the same values in different
strata).
Also, if you have access to design variables for the multistage design you
can use them (but it probably won't make much difference). There's a very
brief example using the National Health Interview Study at
http://faculty.washington.edu/tlumley/survey/example-twostage.html
-thomas