[R-sig-ME] GAMM4: temporal autocorrelation? (GAM, binomial data, random effect)
Tagmarie
Ramgad82 at gmx.net
Wed Mar 14 10:50:58 CET 2018
Dear all,
I am not a statistican but a biologist and I have a problem that I
cannot solve. I guess more people must have that problem but I didn't
find a solution online.
I want to to do a gam with random effects and my response variable has a
binomial error structure. Reading through literature I found that gamm()
doesn't perform very good with binomial error structures and gamm4 would
be better.
So I did a gam using gamm4. My code is like this:
Mod1 <- gamm4(grooming ~s(time,bs =
"cr"),random=~(1|animalID),data=mydata, family=binomial)
The result looks perfect! Unfortunately, when testing for temporal
autocorrelation with
pacf(resid(Mod1$gam))
I do clearly have temporal autocorrelation in my data. I had also
expected that because time is of course always leading to
autocorrelation structures.
My problem:
How do I incorporate the temporal autocorrelation into my model? The
usual part which works in gams (correlation=corAR1(0.71, form = ~ 1 |
animalID) won't work in GAMM4 I know.
I followed an example from "?magic" (after loading mgcv) but that
resulted in a crap looking result.
Does anyone know how to deal with that data structure? Help would be
terribly much appreciated!
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