[R] survreg() provides same results with different distirbutions for left censored data

Thomas Lumley tlumley at uw.edu
Fri Dec 9 01:25:46 CET 2011

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 Lumley
Professor of Biostatistics
University of Auckland

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