Message-ID: <4B50E339.8050304@dryasresearch.com>
Date: 2010-01-15T21:50:49Z
From: Shawn Morrison
Subject: Interpreting Poisson GLM coefficients into everyday language
Is there a readily available function to calculate the effect of
variables from a poisson GLM on the response variable?
My situation is as follows:
I have developed a poisson GLM model and have obtained the coefficients,
SEs, etc However, I am somewhat stuck on interpreting a coefficient in
everyday language.
For example:
Y = dependent variable (count data)
A = independent variable (continuous)
B = independent variable (continuous)
The hypothetical regression equation is:
Y ~ constant + 0.25*A - 0.19*(log(B+1)) [I used natural logs for A]
I want to be able to say that changing B by one unit has a corresponding
___% decrease in Y.
How do I calculate the % change in Y caused by changes in B? Is there an
R function, or a bit of code that will do the trick? How do these
calculations affect the SEs?
Thank you,
***************
Shawn Morrison
Edmonton, Alberta