[Rd] Inconsistency in AIC values for glm with family poisson (PR#8840)

x.sole at iconcologia.net x.sole at iconcologia.net
Mon May 8 12:06:57 CEST 2006

Full_Name: Xavier Solé
Version: 2.3.0
OS: Windows XP SP2
Submission from: (NULL) (

#When computing AIC for one of the models shown in ?glm we get an inconsistent
AIC value. We also get the same wrong value if we use "extractAIC" o "AIC"




#AIC of this model should be 15.129 (residual deviance + 2*effective degrees of
freedom), but the AIC which R returns is 56.76. Function extractAIC returns the
right number of effective degrees of freedom (5), but anyway seems to fail in
calculating the correct AIC value.

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