Message-ID: <45f07ac3-22e0-c901-e8b4-e5748843a0b9@mpi.nl>
Date: 2020-10-03T16:52:51Z
From: Phillip Alday
Subject: Dropping correlations bet. random-effects in lme4 syntax
In-Reply-To: <CACgv6yWeKyybJO6vOZM7B+RbxLSr3K75TdTUfoYrsHKXoS=NXQ@mail.gmail.com>
I have no idea what 0* means, but 0+ means "suppress the intercept"
(which has knock-on effects for categorical variables and whether
they're represented in the model as (nlevels-1) contrasts or nlevels).
For the other things: try it out. The output of summary(m1) will show
you which levels and correlations were kept.
On 03/10/2020 18:44, Simon Harmel wrote:
> Thanks Phillip. What would be the meaning of placing `0 +` next to any
> of the random effects (e.g., B) as shown in m2?
>
> m1 <- lmer(y ~ A * B * C + (A * C | group) + (B|group) , data = data)??
>
> m2 <- lmer(y ~ A * B * C + (A * 0+ B * C ?| group), data = data)??
>
> On Sat, Oct 3, 2020 at 11:33 AM Phillip Alday <phillip.alday at mpi.nl
> <mailto:phillip.alday at mpi.nl>> wrote:
>
> You can split the specification of your grouping to achieve this, at
> least in part:
>
> lmer(y ~ A * B * C + (A * C | group) + (B|group) , data = data)
>
> Note that life gets tricky with the interaction terms.
>
> Phillip
>
> On 03/10/2020 06:35, Simon Harmel wrote:
> > Hello all,
> >
> > I know to drop all correlations among all level-1 predictors in
> the random
> > part of an lmer() call, I can use `||`. But I was wondering how
> to drop
> > correlations (a) "individually" or (b) "in pairs"?
> >
> > Example of (a) is how to drop the correlation of B with others
> (A & C)?
> > Example of (b) is how to drop the correlation between B and C?
> >
> > lmer(y ~ A * B * C + (A * B * C? || group), data = data)
> >
> > Thanks,
> > Simon
> >
> >? ? ? ?[[alternative HTML version deleted]]
> >
> > _______________________________________________
> > R-sig-mixed-models at r-project.org
> <mailto:R-sig-mixed-models at r-project.org> mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models
>
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