Re: [R] Negative intercept in glm poisson model

From: Douglas Bates <bates_at_stat.wisc.edu>
Date: Wed 02 Mar 2005 - 00:31:46 EST

Federico Gherardini wrote:

> I'm trying to fit a glm model using family=poisson(link = "identity"). The
> problem is that the glm function fits a model with a negative intercept,
> which sounds like a nonsense to me, being the response a Poisson variable.

Not really. The negative intercept is on the scale of the linear predictor. The expected response, which is the exponential of the linear predictor, is always positive.



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