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,
[email protected] 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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