[R] coxph and robust variance estimation

[Terry Therneau]

> It seems that the function anova don't use a robust estimation for the
> analysis of deviance.

  You are correct, anova.coxph always uses the partial likelihood

  This is a serious oversight, particularly since some of the situations in 
which the robust variance is recommended are ones where the LR test is invalid. 
It is also a fairly obvious oversight, but I have to admit that I have never 
thought about it --- it only became obvious to me when I saw your note.
  
  I will add this to my list of things to be repaired.
  
  	Terry Therneau