I'm using the Survival package to do a cox regression (coxph) and I can't work out what I'm doing wrong.
My code is
prentice.fit <- coxph(Surv(age_ent, outage, diabetes) ~ a_menopause + cluster(id), data="mydata.cc", ties="breslow")
Value passed to
data argument should not be quoted. You are referring to a variable in your environment, not a string.