I'm using a cox proportional hazards regression to analyze latency data, i.e. time until behavior x occurs. The model I'm running is fitted with the "coxme" package in R (which is a wrapper to the "survival" package if I'm not mistaken) because I wanted to fit a mixed model for the survival analysis. The model converges without problems, however, when I'm trying to test the assumptions of the model I get a fatal error, and my R session crashes. Specifically, when I try to test the "proportional hazard" assumption of the model using the "cox.zph" call, the R session crashes and I don't know why, because the function is supposed to work with both a mixed model (coxme) and a standard, non-mixed, model (which is a "coxph" object in the package terminology). I've tried the non-mixed version of my model and it provides the desired output, but it won't work for my intended model. I've also tried updating RStudio, so I have the latest version, but it didn't help. Finally, I've tried to manually increase the working memory dedicated to RStudio, in case the function was memory demanding, but it didn't help. Looking around at different forums has provided no answers either, both with general search parameters like "causes for R session crash" and more specific, like "cox.zph cause R session crash", but I could not find any help.
Has anyone experienced this error? Were you able to solve it, and if so, how?
I appreciate any advise I can get on this issue.
I am not familiar with that package but you may wish to look at a similar process In our attached paper. Best wishes, David Booth
You said you’ve updated RStudio, have you also tried updating the survival and coxme packages to the latest versions?
ok, im not sure on the complexity of your model that you’re trying to fit, can you try temporarily simplifying it? E.g. remove some of the variables but keep it as a mixed effect model. Just to see if you can get it to work. If it works try slowly building back the complexity of the original model to see at what point it breaks.
Jamie Wallis , yea I've thought along those lines too. However, the full model converges with "coxme", it is just a problem with checking the proportional hazard assumption with the "cox.zph" function that causes the crash. Without the random term, the "cox.zph" function works, it also works when including the random term as a "frailty" argument in the "coxph" function in the "survival" package.
Hey, I am having the same problem - were you able to resolve this Emil? Thanks in advance! Ruth
C. Ruth Archer , I did solve this, or rather the package author solved it. In my case, it was a bug in the function code that prevented it from dealing with a factor parameter. However, that bug was fixed, which leads me to believe that you might have encountered something similar although not the same issue.
Thanks so much Emil Isaksson - really appreciate your taking the time to reply. Thanks!
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