From deleeuw@stat.ucla.edu  Thu Nov 14 01:47:29 2002
From: deleeuw@stat.ucla.edu (Jan de Leeuw)
Date: Wed, 13 Nov 2002 17:47:29 -0800
Subject: survreg (survival) reports erroneous results for left-censored data (PR#2287)
In-Reply-To: <200211132205.XAA24465@pubhealth.ku.dk>
Message-ID: <088EF7B3-F773-11D6-BFC6-000393860F3C@stat.ucla.edu>

Using R-1.6.1 on OS X (Darwin)

Call:
survreg(formula = Surv(c(0, 1, -1), c(T, T, F), type = "left") ~
     1, dist = "gaussian")

Coefficients:
(Intercept)
  -0.2321569

Scale= 1.161135

Loglik(model)= -4.1   Loglik(intercept only)= -4.1
n= 3

No problemo. And, in fact, I get the same results in
the R-1.6.0 Carbon version.

--- Jan

On Wednesday, November 13, 2002, at 02:05 PM, tim@timcohn.com wrote:

> Full_Name: Tim Cohn
> Version: 1.6.1
> OS: Macintosh OS X
> Submission from: (NULL) (130.11.34.250)
>
>
> The Mac version of survreg does not handle left-censored data  
> correctly (at
> least the results are not what I get doing it other ways, and they are  
> not the
> same as I get running R 1.6.1 in Windows 98se;  the Windows 98 results  
> are
> correct).  On the windows version of R 1.6.1.
>
>> survreg(Surv(c(0,1,-1),c(T,T,F),type='left')~1,dist='gaussian')
> Call:
> survreg(formula = Surv(c(0, 1, -1), c(T, T, F), type = "left") ~
>     1, dist = "gaussian")
>
> Coefficients:
> (Intercept)
>  -0.2321569
>
> Scale= 1.161135
>
> Loglik(model)= -4.1   Loglik(intercept only)= -4.1
> n= 3
>
>
> =================
>
> The Macintosh OS X result for the same command is:
>
>> survreg(Surv(c(0,1,-1),c(T,T,F),type='left')~1,dist='gaussian')
> Call:
> survreg(formula = Surv(c(0, 1, -1), c(T, T, F), type = "left") ~
>     1, dist = "gaussian")
>
> Coefficients:
> (Intercept)
>  -0.7373613
>
> Scale= 1.366282
>
> Loglik(model)= -5.6   Loglik(intercept only)= -5.6
> n= 3
>
>
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===
Jan de Leeuw; Professor and Chair, UCLA Department of Statistics;
Editor: Journal of Multivariate Analysis, Journal of Statistical  
Software
US mail: 9432 Boelter Hall, Box 951554, Los Angeles, CA 90095-1554
phone (310)-825-9550;  fax (310)-206-5658;  email: deleeuw@stat.ucla.edu
homepage: http://gifi.stat.ucla.edu
   
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survreg (survival) reports erroneous results for left-censored data (PR#2287)
Jan de Leeuw