> > ... interactions between covariables and time.
>
> A model such as "coxph(Surv(ptime, pstat) ~ age + age*ptime, "
> is invalid -- it is not at all what you think.
Actually what i'm trying to fit is
coxph(Surv(start,end,event)~age+age:start)
to model a time-varying effect \beta(t)
> ... interactions between covariables and time.
A model such as "coxph(Surv(ptime, pstat) ~ age + age*ptime, "
is invalid -- it is not at all what you think. If cph flags this as an
error that is a good thing: I should probably add the same message to
coxph.
> Is is somewhat sensible to
On Wed, Oct 14, 2009 at 9:19 PM, quaildoc wrote:
>
> Some suggested that go into more detail on what I wanted to accomplish and
> the rest of my code. I want to accomplish exactly what Fox did in this
> article( http://www.nabble.com/file/p25897307/appendix-cox-regression.pdf
> appendix-cox-regre
Some suggested that go into more detail on what I wanted to accomplish and
the rest of my code. I want to accomplish exactly what Fox did in this
article( http://www.nabble.com/file/p25897307/appendix-cox-regression.pdf
appendix-cox-regression.pdf ) (starting with page 7), except using "habitat"
Well,
it might be wise to elaborate a bit more about the variables and what
exactly you want e.g. death-time to be. I'd interprete it as time of
death, but the fact that it is 0/1, means it is a logical (?) binary
variable of some sort.
Please ask your question in such a way that somebody who doe
Does anyone have suggestions? Thanks!
quaildoc wrote:
>
> I am having trouble formatting some survival data to use in a time
> dependent cox model. My time dep. variable is habitat and I have it
> recorded for every day (with some NAs). I think it is working properly
> except for calculating th
I am having trouble formatting some survival data to use in a time dependent
cox model. My time dep. variable is habitat and I have it recorded for every
day (with some NAs). I think it is working properly except for calculating
the death.time. This column should be 1s or 0s and as I have it only
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