[R-sig-ME] glmmTMB: testing for temporal variation in effect of fixed predictor on response variable

[Brenna Levine]

Dr. Bolker,

I'm hoping that I might be able to bother you with a quick question. I am
trying to *test whether there is significant temporal variation in the
effect of a fixed predictor on my response variable *with a model in which
year is specified as a random effect (I have 20 years of data). Currently,
I am doing this by fitting an interaction between the fixed effect and the
random effect of year as* (1|year:fixed)* (per a recommendation that I saw
on RSeek.org at some point and some tips that I have read on this
list-serve), and am testing the significance of this random interaction
with a LRT (i.e., with a model lacking this interaction).

Could you tell me if (a) (1|year:fixed) is the correct way to specify this,
and (b) if not, do you have a recommendation for how I should specify this
interaction to test for temporal variation in the effect of a fixed
predictor on my response variable?

Thanks.

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