I'm attempting to understand how R's coxph() accepts and handles repeated entries for subjects (or patient/customer if you prefer). Some call this Long format, others call it 'repeated measures'.
See for example the data set that includes the ID column in the Answers section at:
Also assume covariates are time-varying throughout and there is exactly one censor (i.e. event) variable, which is binary.
1) In the above link's answer, if ID is not given as a parameter in the call to coxph() should the results be the same as including cluster(ID) as a parameter in coxph()?
I attempted to search for documentation, but the following doesn't seem to clearly address (1): https://stat.ethz.ch/pipermail/r-help//2013-July/357466.html
2) If the answer to (1) is 'no', then (mathematically) why? It seems cluster() in coxph() seeks correlations between subjects as per subsection 'cluster' on pg. 20 at
3) Vague question: how does coxph() with repeated measures compare to R's frailtypack regression methods?
The following hints at using cluster(ID):
GEE approach: add "+ cluster(subject)" to the model statement in coxph Mixed models approach: Add " + (1|subject)" to the model statment in coxme.
Thanks in advance!