R help - Feb 2006 - Survreg(), Surv() and interval-censored data

Can survreg() handle interval-censored data like the documentation
says?  I ask because the command:

     survreg(Surv(start, stop, event) ~ 1, data = heart)

fails with the error message

     Invalid survival type

yet the documentation for Surv() states:

     "Presently, the only methods allowing interval censored data are
      the parametric models computed by 'survreg'"

Any pointers as to what I'm missing?

Stephen

--
Richards Consulting
+44(0)131 315 4470
Visit http://www.richardsconsulting.co.uk to download presentations
and papers on longevity risk, or to use our online calculation tools.

A subscription service is available for those companies wishing to
stay at the forefront of understanding the financial aspects of
longevity risk.
Visit http://www.richardsconsulting.co.uk/service.html for more details.

Services are provided by Stephen Richards Consulting Ltd, a
limited-liability company registered in Scotland, number SC144342.

How have you defined "event?"

library(survival)
?Surv

event: The status indicator, normally 0=alive, 1=dead.  Other
          choices are T/F (TRUE = death) or 1/2 (2=death). For interval
          censored data, the status indicator is 0=right censored, 1         
event at 'time', 2=left censored, 3=interval censored.
          Although unusual, the event indicator can be omitted, in
          which case all subjects are assumed to have an event.



Charles Annis, P.E.

Charles.Annis at StatisticalEngineering.com
phone: 561-352-9699
eFax:  614-455-3265
http://www.StatisticalEngineering.com
 

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Stephen Richards
Sent: Monday, February 13, 2006 11:45 AM
To: r-help at stat.math.ethz.ch
Subject: [R] Survreg(), Surv() and interval-censored data

Can survreg() handle interval-censored data like the documentation
says?  I ask because the command:

     survreg(Surv(start, stop, event) ~ 1, data = heart)

fails with the error message

     Invalid survival type

yet the documentation for Surv() states:

     "Presently, the only methods allowing interval censored data are
      the parametric models computed by 'survreg'"

Any pointers as to what I'm missing?

Stephen

--
Richards Consulting
+44(0)131 315 4470
Visit http://www.richardsconsulting.co.uk to download presentations
and papers on longevity risk, or to use our online calculation tools.

A subscription service is available for those companies wishing to
stay at the forefront of understanding the financial aspects of
longevity risk.
Visit http://www.richardsconsulting.co.uk/service.html for more details.

Services are provided by Stephen Richards Consulting Ltd, a
limited-liability company registered in Scotland, number SC144342.

______________________________________________
R-help at stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html

On Mon, 13 Feb 2006, Stephen Richards wrote:
> Can survreg() handle interval-censored data like the documentation
> says?  I ask because the command:
>
>     survreg(Surv(start, stop, event) ~ 1, data = heart)
>
> fails with the error message
>
>     Invalid survival type
>
> yet the documentation for Surv() states:
>
>     "Presently, the only methods allowing interval censored data are
>      the parametric models computed by 'survreg'"
>
> Any pointers as to what I'm missing?
>
You are specifying left-truncated, right-censored data, not 
interval-censored. You need the type= argument, eg
> Surv(c(1,1,NA,3),c(2,NA,2,3),type="interval2")
[1] [1, 2] 1+     2-     3

specifies interval censoring at [1,2], right-censoring at 1, 
left-censoring at 2, and an observed event at 3.

 	-thomas