R help - Sep 2009 - R^2 for poisson and zero inflated regressions

Dear all,
I'm performing poisson regressions using the glm(family=poisson) and
zero-inflated regressions using the zeroinfl from the package pscl. However
any of those give an R^2 and I was wondering if there is a way to get it.

 Thanks

-- 
Maria Sagot
Graduate Student
107 Life Sciences Building
Department of Biological Sciences
Louisiana State University
Phone: 225.578.4284

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On 15/09/2009, at 9:11 AM, Maria Sagot wrote:
> Dear all,
> I'm performing poisson regressions using the glm(family=poisson) and
> zero-inflated regressions using the zeroinfl from the package pscl.  
> However
> any of those give an R^2 and I was wondering if there is a way to  
> get it.
R^2 is meaningless for such models.  They are fitted via maximum
likelihood, not least squares.

	cheers,

		Rolf Turner

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