Message-ID: <1292266341.28092.6.camel@punchbuggy>
Date: 2010-12-13T18:52:21Z
From: Terry Therneau
Subject: survival package - calculating probability to survive a given time
In-Reply-To: <mailman.31.1292065207.30224.r-help@r-project.org>
- ------- included message --------
i try to calculate the probabilty to survive a given time by using the
estimated survival curve by kaplan meier.
What is the right way to do that? as far as is see i cannot use the
predict-methods from the survival package?
---- end inclusion --------
The survfit function directly estimates the probability you want, no
predict method is needed. It is similar to quantile(x, 1:9/10), in that
you would not use predict on that either.
As to getting the value at a specific time, use
summary(fit, time=20)
This correctly interpolates the step function when "20" is exactly one
of the event times.
Terry Therneau