[R-meta] Testing multicollinearity between categorical predictors

[Rafael Rios]

 Dear Wolfgang,

Yes, it is. Yes and no for each moderator. I am also evaluating their
interaction.

All the best,

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 10:12, Viechtbauer, Wolfgang (SP) <
wolfgang.viechtbauer using maastrichtuniversity.nl> escreveu:

> I am not sure I fully understand. Are you saying that the two moderators
> have two levels each?
>
> Best,
> Wolfgang
>
> >-----Original Message-----
> >From: Rafael Rios [mailto:biorafaelrm using gmail.com]
> >Sent: Friday, 19 June, 2020 15:02
> >To: Michael Dewey
> >Cc: Viechtbauer, Wolfgang (SP); r-sig-meta-analysis using r-project.org
> >Subject: Re: [R-meta] Testing multicollinearity between categorical
> >predictors
> >
> >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
> >Research Gate: https://www.researchgate.net/profile/Rafael_Rios_Moura2
> >Rios de Ciência: https://www.youtube.com/channel/UCu2186wIJKji22ai8tvlUfg
> >
> >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
>

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