I can measure two variables on each patient in a survival study (I have the measurements and the survival times; some patients outlive the study and are therefore censored). I know that it is possible to use either of these variables to assign patients to groups with different survival curves (using a simple threshold on the variables). What I want to know is whether using both variables allows me to assign patients better than just one of the variables — i.e., whether the survival characteristics are more different when both variables are included; whether a given variable provides information that the other one doesn't.
I would prefer to do this in a Bayesian manner using JAGS (BUGS); I tend to find these models easier to understand.
Thanks in advance.