[R] svycoxph and test statistics

[Chirag Patel]

Hello,
I have been using the function 'svycoxph' in the Dr. Lumley's survey package (version 3.26) to compute coefficient estimates for Cox regression.

I have noticed the p-values output are based on normal distribution (like in coxph); however in svyglm (and in other software, such as Stata or SAS) the p-values are computed via the t distribution with degrees of freedom equal to the number of PSUs minus number of strata.

I am wondering why there is a difference here?  

Thank you very much,

Chirag Patel
Stanford University
cjp at stanford.edu