R help - Dec 2011 - survreg() provides same results with different distirbutions for left censored data

Hello,

I'm working with some left censored survival data using accelerated failure
time models.  I am interested in fitting different distributions to the data
but seem to be getting the same results from the model fit using survreg
regardless of the assumed distribution.

These two codes seem to provide the same results:

aft.gaussian <- summary(survreg(Surv(y,y>0),type="left")~
group),dist="gaussian")
          
aft.weibull <- summary(survreg(Surv(y,y>0),type="left")~
group),dist="weibull")

Thanks,

Carmen

--
View this message in context:
http://r.789695.n4.nabble.com/survreg-provides-same-results-with-different-distirbutions-for-left-censored-data-tp4169671p4169671.html
Sent from the R help mailing list archive at Nabble.com.

On Thu, Dec 8, 2011 at 3:55 AM, ifejobi <ifejobi at gmail.com>
wrote:
> Hello,
>
> I'm working with some left censored survival data using accelerated
failure
> time models. ?I am interested in fitting different distributions to the
data
> but seem to be getting the same results from the model fit using survreg
> regardless of the assumed distribution.
>
> These two codes seem to provide the same results:
>
> aft.gaussian <- summary(survreg(Surv(y,y>0),type="left")~
> group),dist="gaussian")
>
> aft.weibull <- summary(survreg(Surv(y,y>0),type="left")~
> group),dist="weibull")
>
That's because you're fitting the same model: the dist= argument needs
to be inside the parentheses for survreg().

   -thomas

-- 
Thomas Lumley
Professor of Biostatistics
University of Auckland