[R] transforming data glm

Mcdonald, Grant grant.mcdonald08 at imperial.ac.uk
Mon Aug 24 12:47:57 CEST 2009

Dear sir,

I am fitting a glm with default identity link:


the model is overdisperesed and plot model shows a low level of linearity of the residuals.  The overdispersion and linearity of residulas on the normal Q-Q plot is corrected well by using:


Boxcox of my model also suggests that the log transformation is what i should do.

I ask how i am able to do this by changing the link function or error family of my glm and not diretly taking the log of the response variable.  

For instance:
model<-glm(log(timetoacceptsecs)~maleage*maletub*relweight*malemobtrue*femmobtrue, family=poisson))
does not improve my model in terms of overdispersion etc as much as taking the log.

Thank you

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