[R-meta] Testing multicollinearity between categorical predictors

[Rafael Rios]

 Dear Michael,

Thank you for the reply. I am evaluating the biases arising from pooling
samples from different populations and periods on the average effect size.
Therefore, I included both pooling practices, and their interaction as
moderators. Each practice has two levels (yes and no).

Best wishes,

Rafael.
_______________________________________________________

*Prof. Dr. Rafael Rios Moura*

*sciencia amabilis *
Coordenador de Pesquisa e do NEPEE/CNPq
Laboratório de Ecologia e Zoologia (LEZ)
UEMG - Unidade Ituiutaba

ORCID: http://orcid.org/0000-0002-7911-4734
Currículo Lattes: http://lattes.cnpq.br/4264357546465157
<http://orcid.org/0000-0002-7911-4734>
<http://lattes.cnpq.br/4264357546465157>
<http://lattes.cnpq.br/4264357546465157>Research Gate:
https://www.researchgate.net/profile/Rafael_Rios_Moura2
<http://orcid.org/0000-0002-7911-4734>
Rios de Ciência: https://www.youtube.com/channel/UCu2186wIJKji22ai8tvlUfg
<http://orcid.org/0000-0002-7911-4734>


Em sex., 19 de jun. de 2020 às 09:50, Michael Dewey <lists using dewey.myzen.co.uk>
escreveu:

> Dear Rafael
>
> It is hard to answer here because we do not know what scientific problem
> the referee thinks he or she has spotted which would be solved by such a
> test. Being of a cynical world view I suspect neither does the referee
> and this is a conditioned reflex like Pavlov's dog salivating at the bell.
>
> Are the two moderators of scientific interest to you or are you
> including them so you can say that there is still residual heterogeneity
> even after you did your best to explain it? In the latter case I would
> suggest collinearity is irrelevant.
>
> Michael
>
> On 19/06/2020 13:36, Rafael Rios wrote:
> > Dear Wolfgang,
> >
> > Thank you for the replay. I also thought about using VIF to evaluate
> > multicollinearity, but there is a lot of criticism about the
> applicability
> > of VIF for categorical predictors. There is a variation called GVIF.
> > However, since the meta-analysis changes categorical predictors to dummy
> > variables, I could not use it in R. I am not sure whether this is the
> best
> > approach. Do you not other methods to evaluate or avoid potential
> > multicollinearity among categorical moderators?
> >
> > Best wishes,
> >
> > Rafael.
> > _______________________________________________________
> >
> > *Prof. Dr. Rafael Rios Moura*
> >
> > *sciencia amabilis *
> > Coordenador de Pesquisa e do NEPEE/CNPq
> > Laboratório de Ecologia e Zoologia (LEZ)
> > UEMG - Unidade Ituiutaba
> >
> > ORCID: http://orcid.org/0000-0002-7911-4734
> > Currículo Lattes: http://lattes.cnpq.br/4264357546465157
> > <http://orcid.org/0000-0002-7911-4734>
> > <http://lattes.cnpq.br/4264357546465157>
> > <http://lattes.cnpq.br/4264357546465157>Research Gate:
> > https://www.researchgate.net/profile/Rafael_Rios_Moura2
> > <http://orcid.org/0000-0002-7911-4734>
> > Rios de Ciência:
> https://www.youtube.com/channel/UCu2186wIJKji22ai8tvlUfg
> > <http://orcid.org/0000-0002-7911-4734>
> >
> >
> > Em sex., 19 de jun. de 2020 às 05:40, Viechtbauer, Wolfgang (SP) <
> > wolfgang.viechtbauer using maastrichtuniversity.nl> escreveu:
> >
> >> Dear Rafael,
> >>
> >> I don't know what "testing" for multicollinearity would entail. One
> could
> >> examine the variance inflation factors with vif(). What VIF values are
> >> considered "large" is debatable though.
> >>
> >> Best,
> >> Wolfgang
> >>
> >>> -----Original Message-----
> >>> From: Rafael Rios [mailto:biorafaelrm using gmail.com]
> >>> Sent: Wednesday, 17 June, 2020 2:28
> >>> To: Viechtbauer, Wolfgang (SP); r-sig-meta-analysis using r-project.org
> >>> Subject: Testing multicollinearity between categorical predictors
> >>>
> >>> Dear Wolfgang and All,
> >>>
> >>> Is there a good method for testing multicollinearity between
> categorical
> >>> predictors in meta-regression? I ran a mixed-effects MLMA using two
> >>> categorical predictors and their interaction as moderators, but a
> Referee
> >>> requested a test of multicollinearity. I did not find a good approach
> to
> >>> solve this problem. Thank you in advance.
> >>>
> >>> Best wishes,
> >>> _______________________________________________________
> >>>
> >>> Prof. Dr. Rafael Rios Moura
> >>> sciencia amabilis
> >>> Coordenador de Pesquisa e do NEPEE/CNPq
> >>> Laboratório de Ecologia e Zoologia (LEZ)
> >>> UEMG - Unidade Ituiutaba
> >>>
> >>> ORCID: http://orcid.org/0000-0002-7911-4734
> >>> Currículo Lattes: http://lattes.cnpq.br/4264357546465157
> >>> Research Gate: https://www.researchgate.net/profile/Rafael_Rios_Moura2
> >>> Rios de Ciência:
> https://www.youtube.com/channel/UCu2186wIJKji22ai8tvlUfg
> >>
> >
> >       [[alternative HTML version deleted]]
> >
> > _______________________________________________
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> > R-sig-meta-analysis using r-project.org
> > https://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis
> >
>
> --
> Michael
> http://www.dewey.myzen.co.uk/home.html
>

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