Why do I get different sign of the coefficients of covariates when I run the semi-parametric proportional hazard model (coxph) compared to the parametric proportional hazard model (survreg)?
Survreg models the time till death, a postive coefficient --> a longer time. Coxph models the death rate, a positive coefficient --> higher death rate. So in the first a positive is good, in the second it is bad.
Anyone with experience in extracting information form survreg to make predictions are free to contact me.
Commonly one would use predict(fit) to get predictions. There are several options. Terry Therneau