stratum with only one PSU

[amt9008]

Trying to analyze a national sample (NHAMCS), which I've restricted to a certain population (patient visits with a particular diagnosis).
The survey uses a four-stage probability design with samples of PSUs, hospitals within PSUs, clinics within hospitals, and patient visits within clinics.
After dropping the observations unrelated to the population of interest, and using the "svy" command for descriptive statistics, I get a note that I am "missing test statistics because of stratum with single sampling unit".

I've done my due diligence as far as troubleshooting the problem, and used "svydes" to identify the stratum with a singleton PSU. It turns out there is only ONE observation that falls into that category. I'd like to drop that observation, but the problem is that the stratum and PSU variables are masked in this public dataset, so "list strata psu if strata==1" command returns with a blank.

Any ideas as to how to address this issue with masked variables?

Thanks!

[Clyde Schechter]

Well, if the stratum and psu variables are not available, how are you even -svyset-ing your data? Without doing that, the -svy:- prefix doesn't do anything anyway (except give you a message that your data are not -svyset-).

Are you saying that there is a unique observation in your data set for which the stratum and psu variables have missing values, and that Stata is complaining that this is a stratum with a singleton PSU? If so, just drop that observation. Otherwise, I don't understand what you're asking.

[amt9008]

the names of the stratum and psu variables are available, but not their values. but i think i found a solution:
svydescribe, single generate(A)
drop if A==1

i confirmed that the number of observations for which A==1 is the same as the number identified with an asterisk when using svydesc, and stata is now able to calculate the standard error/confidence intervals for my descriptive statistics.

thanks for your help!