Hi, I am just wondering if there is a test available for testing if a linear
fit of an independent variable in a Cox regression is enough? Thanks for any
suggestions.
John Zhang
[[elided Yahoo spam]]
> On examining non-linearity of Cox coefficients with penalized splines - I
> have not been able to dig up a completely clear description of the test
> performed in R or S-plus.
One "iron clad" way to test is to fit a model that has the variable of
interest
"x" as a linear term, then a second
> -Original Message-
> From: [EMAIL PROTECTED] on behalf of array chip
> Sent: Fri 5/9/2008 2:54 PM
> To: [EMAIL PROTECTED]
> Subject: [R] how to check linearity in Cox regression
> Hi, I am just wondering if there is a test available for testing if a linear
>
Use pspline within a Cox model. It includes a fairly general test for
nonlinearity, that is similar to GAM models.
Terry Therneau
> coxph(Surv(time, status) ~ ph.ecog + pspline(age), lung)
Call:
coxph(formula = Surv(time, status) ~ ph.ecog + pspline(age),
data = lung)
On examining non-linearity of Cox coefficients with penalized splines - I
have not been able to dig up a completely clear description of the test
performed in R or S-plus.
>From the Therneau and Grambsch book (2000 - page 126) I gather that the test
reported for "linear" has as its null hypothesi
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