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Re: st: Constraint, Poisson, & pseudo R^2


From   Rkaminski@aol.com
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Constraint, Poisson, & pseudo R^2
Date   Tue, 19 Oct 2004 17:05:05 EDT

Dave - thanks for your reply.  I'm not using Scott's add on for the  model 
estimation. Interestingly, Stata version 7 provides the pseudo-R^2 value  when 
using the constraint, but version 8 does not.  This makes me think  Stata 
intentionally eliminated it from the output in the latest incarnation.  Hopefully 
someone will know the reason why. Maybe it is not appropriate to  report the 
R^2 value under these conditions?
 
Bob Kaminski
Dept. of Criminology & Criminal Justice
University  of South Carolina


In a message dated 10/19/2004 1:50:37 PM Eastern Standard Time,  
jacobs.184@sociology.osu.edu writes:

That's almost certainly because Long and Freeze use their add on program  
that calculates psuedo R squares.  I can't remember the name of the add  on 
program, but it is listed repeatedly in the Long and Freeze  book.

Dave Jacobs
Ohio State

At 08:00 AM 10/19/2004 -0400, you  wrote:
>In the Long & Freeze book published by  Stata, the  authors estimate a 
Poisson
>regression model using the constraint   command to control for unequal
>exposure. It produces the same  coefficients as  when using exposure or 
>offset, but
>the  pseudo-R^2 value is substantially larger  when using the constraint  
>option
>(p. 265). However, when I use the constraint  option,  Stata does not 
>produce a
>pseudo-R^2 value. Does anyone know  whether  there has been a change made to
>the program by  Stata?
>
>Thanks in  advance.
>
>Bob  Kaminski
>
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