[R-sig-ME] Model selection in GAMM

[Mari Laine]

Hi!

I'm using GAMM (mgcv::gamm) to fit non-Gaussian models with several fixed factors and also a temporal structure. Additionally, I'm fitting non-linearity with smoothers. I have several correlated main effect candidates, and I would like to compare their GAMMs and see, which one of the models best fits the data. I would also need to tune the models via dropping unnecessary smoothers (linear ones) and non-significant fixed variables.

After going through some statistical books, I'm under the impression that one should not use AIC comparison of $lme's for GAMM models - is this correct? Could someone give instruction on the model selection in GAMM or refer me to a book / some other source of information on this matter?

Thanks,

   Mari Laine