I am running a mixed effects cox model using coxme in R, and I cannot find any information on how to check model assumptions for this type of model. I have seen the older chats, which have recommended using a frailty term in a regular cox model instead, but I have two random effects so this would not work for me. Since the last time a similar question was posted was 8 years ago (here), I was hoping there had been some developments and that someone had found a solution to this?
In summary, how to validate PH (and other assumptions) for mixed effects cox model (with more than one random effect) fit using coxme in R?
