Your question has two levels: 1. What is the right model for this data 2. Can model __ be fit
Wrt 2 and coxme: For a reliable fit you need to have more events than random effects. Thus for patient/tissue I would want to see multiple events per patient/tissue pair. This is statistical issue -- when there are too few events the confidence intervals for the random effects end up being a mile wide. (Exception, if the number of events is very large, >10^5 say as sometimes occurs in economics studies, the estimates can work.) coxme works fine with start,stop data. Wrt question 1. Your models assume that marker1, marker2, ... each have the same effect across tissue types. Adding a random effect gave per subject or per subject/tissue intercepts. Do you instead want to do shrinkage of the marker1, .. coefficients? Terry Therneau ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
