st: using srvyset with survival analysis

[Sharon Minnick <slminnick@ucdavis.edu>]

Hello,

In Stata10, I have been attempting to analyze my survival data with cox 
regression while accounting for the sampling design and I always get 
this error:

the stset ID variable is not nested within the final stage sampling unit

Originally I thought this might be because some of our subjects moved 
during the study and so they change strata and cluster from where they 
were originally sampled.  But I just tried creating a temporary variable 
that holds the strata constant for each subject and dropped the cluster 
variables and I still get the same error.

So my srvyset code is:

svyset _n, strata(staticzone) vce(linearized) singleunit(missing)

and the cox regression code is:

svy: stcox agegrp male

If I change the svyset code to use my subject ID variable instead of _n, 
then I get this error:

no observations;
stset and subpop() option identify disjoint subsets of the data

which I don't understand since I am not using a subpop option.

Any help would be appreciated,

thanks,

Sharon Minnick
UC Davis
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/