Message-ID: <1325287199.27944.0.camel@milan>
Date: 2011-12-30T23:19:58Z
From: Milan Bouchet-Valat
Subject: Calculate survival function for AFT model
In-Reply-To: <1325278001371-4246799.post@n4.nabble.com>
Le vendredi 30 d?cembre 2011 ? 12:46 -0800, thebennjammin a ?crit :
> I have fit an accelerated failure time model using coxph, and have what seems
> to be a simple question that I can't figure out.
Please specify the exact package, functions and actual code you use.
coxph(), as the name says, runs a Cox *proportional hazards* model,
which is different from an accelerated failure time model. You should
use survreg (package survival) if you want to run the later family.
> Given a vector of predictor values X, the survival time S[t|X] is the
> probability the entity will survive longer than some time t. Now, how do I
> calculate this for a specific value of t?
Package rms offers convenience functions to compute and plot this. See
psm() and predict.psm().
Regards