[R-sig-ME] Question on random effect

[Joaquín Aldabe]

Thank you Ben. Another question: is there any kind of R2 in mixed models
that allow me to estimate the explanatory power of the model?
Thanks again. Joaquin

2017-07-11 8:22 GMT-03:00 Ben Bolker <bbolker at gmail.com>:

> Yes, the assumption is that the random effects are (conditionally)
> independent.  It can help to specify covariates  (such as
> latitude/longitude or eastings/northings, or environmental conditions
> [temperature, elevation, etc.]) for sites to mop up some of the
> independence. It is theoretically possible, although I don't know of
> an easy off-the-shelf way to do it, to impose (e.g.) spatial
> correlation structures at the level of the random effects ...  or you
> could examine the spatial dependence of the conditional modes/random
> effects and try to convince yourself it was weak ...
>
> On Tue, Jul 11, 2017 at 7:14 AM, Joaquín Aldabe
> <joaquin.aldabe at gmail.com> wrote:
> > Hi all, when working with mixed models, do the levels of the random
> effect
> > have to be independent? For example, if my random effect is the identity
> of
> > sites and it is associated to the intercept, do sites have to be
> > independent?
> >
> > I appreciate comments and bibliographic references.
> >
> > Thank you very much in advanced,
> >
> > Joaquin
> >
> > --
> > *Joaquín Aldabe*
> >
> > *Grupo Biodiversidad, Ambiente y Sociedad*
> > Centro Universitario de la Región Este, Universidad de la República
> > Ruta 15 (y Ruta 9), Km 28.500, Departamento de Rocha
> >
> > *Departamento de Conservación*
> > Aves Uruguay
> > BirdLife International
> > Canelones 1164, Montevideo
> >
> > https://sites.google.com/site/joaquin.aldabe
> > <https://sites.google.com/site/perfilprofesionaljoaquinaldabe>
> >
> >
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-- 
*Joaquín Aldabe*

*Grupo Biodiversidad, Ambiente y Sociedad*
Centro Universitario de la Región Este, Universidad de la República
Ruta 15 (y Ruta 9), Km 28.500, Departamento de Rocha

*Departamento de Conservación*
Aves Uruguay
BirdLife International
Canelones 1164, Montevideo

https://sites.google.com/site/joaquin.aldabe
<https://sites.google.com/site/perfilprofesionaljoaquinaldabe>

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