[R] how to check linearity in Cox regression

2008-05-09 Thread array chip
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]]

[R] how to check linearity in Cox regression

2008-11-26 Thread Terry Therneau
> 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

Re: [R] how to check linearity in Cox regression

2008-05-09 Thread Steven McKinney
> -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 >

Re: [R] how to check linearity in Cox regression

2008-05-12 Thread Terry Therneau
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)

Re: [R] how to check linearity in Cox regression

2008-11-25 Thread Michael Margolis
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