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survreg (survival) reports erroneous results for left-censored data (PR#2287)

5 messages · tim@timcohn.com, Thomas Lumley, Jan de Leeuw +1 more

#
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.
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:
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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#
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:

            
===
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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#
On Wed, 13 Nov 2002, Jan de Leeuw wrote:

            
I don't. Could there be a G3/G4 issue?

	-thomas
Thomas Lumley			Asst. Professor, Biostatistics
tlumley@u.washington.edu	University of Washington, Seattle
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#
I take that back. I now get the "correct" result on Darwin R-1.6.1, the  
"wrong" result
with Carbon R-1.6.0. On a dual G4 with 10.2.2.
On Thursday, November 14, 2002, at 08:04 AM, Thomas Lumley wrote:

            
===
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
   
------------------------------------------------------------------------ 
-------------------------
           No matter where you go, there you are. --- Buckaroo Banzai
                    http://gifi.stat.ucla.edu/sounds/nomatter.au
   
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#
Thank you for looking into this so quickly.  As you correctly surmise,  
I was using the Carbon version of R-1.6.1 on Mac OS 10.2.2 (Jaguar)  
when I got the "wrong" answers.

One other observation:  The right censoring seems to work fine.

Thanks again,

Tim
On Thursday, November 14, 2002, at 11:09 AM, Jan de Leeuw wrote:

            
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