From tim@timcohn.com  Fri Nov 15 00:47:46 2002
From: tim@timcohn.com (Tim Cohn)
Date: Thu, 14 Nov 2002 19:47:46 -0500
Subject: survreg (survival) reports erroneous results for left-censored
 data (PR#2287)
In-Reply-To: <733B8BF8-F7EB-11D6-91DB-000393860F3C@stat.ucla.edu>
Message-ID: <DB8072B2-F833-11D6-83DE-000393479732@timcohn.com>

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:

> 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:
>
>> On Wed, 13 Nov 2002, Jan de Leeuw wrote:
>>
>>>
>>> No problemo. And, in fact, I get the same results in
>>> the R-1.6.0 Carbon version.
>>
>> I don't. Could there be a G3/G4 issue?
>>
>> 	-thomas
>>
>>
>>> --- 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
>>>
>>> --------------------------------------------------------------------- 
>>> ---
>>> -------------------------
>>>            No matter where you go, there you are. --- Buckaroo Banzai
>>>                     http://gifi.stat.ucla.edu/sounds/nomatter.au
>>>
>>> --------------------------------------------------------------------- 
>>> ---
>>> -------------------------
>>>
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>>> r-devel mailing list -- Read  
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>>>
>>
>> Thomas Lumley			Asst. Professor, Biostatistics
>> tlumley@u.washington.edu	University of Washington, Seattle
>> ^^^^^^^^^^^^^^^^^^^^^^^^
>>- NOTE NEW EMAIL ADDRESS
>>
>>
> ===
> 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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survreg (survival) reports erroneous results for left-censored data (PR#2287)
Tim Cohn