Re: [R] Apparently Conflicting Results with coxph

2007-10-03 Thread Terry Therneau
> I thought about this some more, and I'm not sure that possibility is > "to blame." In my time-dependent model, I don't think I'm doing > anything different than is done for transplant in the Stanford > Heart Study (the often used example for this kind of time-dependent > covariate). As in my ca

Re: [R] Apparently Conflicting Results with coxph

2007-10-02 Thread Terry Therneau
From my experience, what you are seeing is almost certainly a patient selection effect. (The number 1 reason for puzzling results is incorrect coding of a time-dependent covariate, but you appear to have been quite careful). Assigning the implant as a non-time dependent covariate almost

Re: [R] Apparently Conflicting Results with coxph

2007-10-02 Thread Charles C. Berry
On Tue, 2 Oct 2007, Kevin E. Thorpe wrote: > Kevin E. Thorpe wrote: >> Peter Dalgaard wrote: >>> Kevin E. Thorpe wrote: Dear List: I have a data frame prepared in the couting process style for including a binary time-dependent covariate. The first few rows look like this.

Re: [R] Apparently Conflicting Results with coxph

2007-10-02 Thread Kevin E. Thorpe
Kevin E. Thorpe wrote: > Peter Dalgaard wrote: >> Kevin E. Thorpe wrote: >>> Dear List: >>> >>> I have a data frame prepared in the couting process style for including >>> a binary time-dependent covariate. The first few rows look like this. >>> >>> PtNo StartEnd Status Imp >>> 1 1

Re: [R] Apparently Conflicting Results with coxph

2007-10-01 Thread Kevin E. Thorpe
Peter Dalgaard wrote: > Kevin E. Thorpe wrote: >> Dear List: >> >> I have a data frame prepared in the couting process style for including >> a binary time-dependent covariate. The first few rows look like this. >> >> PtNo StartEnd Status Imp >> 1 1 0 608.0 0 0 >> 2 2

Re: [R] Apparently Conflicting Results with coxph

2007-10-01 Thread Peter Dalgaard
Kevin E. Thorpe wrote: > Dear List: > > I have a data frame prepared in the couting process style for including > a binary time-dependent covariate. The first few rows look like this. > > PtNo StartEnd Status Imp > 1 1 0 608.0 0 0 > 2 2 0 513.0 0 0 > 3

[R] Apparently Conflicting Results with coxph

2007-10-01 Thread Kevin E. Thorpe
Dear List: I have a data frame prepared in the couting process style for including a binary time-dependent covariate. The first few rows look like this. PtNo StartEnd Status Imp 1 1 0 608.0 0 0 2 2 0 513.0 0 0 3 2 513 887.0 0 1 4 3