Dear all,
I'm struggling with predicting expected time until death for a coxph and
survreg model.
I have two datasets. Dataset 1 includes a certain number of people for which
I know a vector of covariates (age, gender, etc.) and their event times
(i.e., I know whether they have died and when if
On Nov 11, 2010, at 3:44 AM, Michael Haenlein wrote:
Dear all,
I'm struggling with predicting expected time until death for a
coxph and
survreg model.
I have two datasets. Dataset 1 includes a certain number of people
for which
I know a vector of covariates (age, gender, etc.) and their
Indeed, from the predict() function of the coxph you cannot get
directly time predictions, but only linear and exponential risk
scores. This is because, in order to get the time, a baseline hazard
has to be computed and it is not straightforward since it is implicit
in the Cox model.
2010/11/11
Thanks very much for your answers, David and Mattia.
I understand that the baseline hazard in a Cox model is unknown and that
this makes the calculation of expected survival difficult.
Does this change when I move to a survreg model instead?
I think I'm OK with estimating a Cox model (or a
Michael,
You are looking to compute an estimated time to death -- rather than the
odds of death conditional upon time. Thus, you will want to use time to
death as your dependent variable rather than a dichotomous outcome (
0=alive, 1=death). You can accomplish this with a straight forward
Thanks for the comment, James!
The problem is that my initial sample (Dataset 1) is truncated. That means I
only observe time to death for those individuals who actually died before
end of my observation period. It is my understanding that this type of
truncation creates a bias when I use a
On Nov 11, 2010, at 12:14 PM, Michael Haenlein wrote:
Thanks for the comment, James!
The problem is that my initial sample (Dataset 1) is truncated. That
means I
only observe time to death for those individuals who actually died
before
end of my observation period. It is my understanding
David, Mattia, James -- thanks so much for all your helpful comments!
I now have a much better understanding of how to calculate what I'm
interested in ... and what the risks are of doing so.
Thanks and all the best,
Michael
On Thu, Nov 11, 2010 at 7:33 PM, David Winsemius
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