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From: Frank Harrell [mailto:harre...@gmail.com] On Behalf Of Frank Harrell
Sent: Thursday, September 02, 2010 4:23 PM
To: Bond, Stephen
Cc: r-help@r-project.org
Subject: Re: [R] Comparing COXPH models, one with age as a continuous variable,
one with age as a three-level factor
On Thu, 2 Sep
On Thu, 2 Sep 2010, stephenb wrote:
sorry to bump in late, but I am doing similar things now and was browsing.
IMHO anova is not appropriate here. it applies when the richer model has p
more variables than the simpler model. this is not the case here. the
competing models use different variabl
sorry to bump in late, but I am doing similar things now and was browsing.
IMHO anova is not appropriate here. it applies when the richer model has p
more variables than the simpler model. this is not the case here. the
competing models use different variables.
you are left with IC.
by transfo
?anova.coxph
will tell you that there's an additional parameter, test, taking
values "F", "Cp", or "Chisq" which instructs the anova method to
perform the stated test comparing the two models and spit out a p-
value (for F and Chisq at least).
example(anova.chisq) provides some examples.
Che
Windows XP
R 2.8.1
I am trying to use anova(fitCont,fitCat) to compare two Cox models (coxph) one
in which age is entered as a continuous variable, and a second where age is
entered as a three-level factor (young, middle, old). The Analysis of Deviance
Table produced by anova does not give a p
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