[R] interval-censored data in coxph

[Thomas Lumley]

On Fri, 21 May 2004, array chip wrote:

> Hi,
>
> I am wondering how to specify interval-censored data
> in coxph? The example in the help page
>
> summary(coxph(Surv(start, stop, event) ~ x, data =
> test2))
>
> is for counting process data, is the counting process
> data the same as interval-censored data?
>

No. You can't use interval-censored data in the Cox model, only in the
parametric survival models (survreg()).

There are two ways of specifying interval-censored data.  In the
simpler one the syntax is  Surv(before,after, type="interval2")

Here 'before' is the start of the interval and after is the end of the
interval.  You can combine this with exact failure times (before==after)
and right-censoring (after=NA) and left censoring (before=NA).


	-thomas