[R-meta] Overlapping CIs with significant difference among subgroups

[Rafael Rios]

Dear Dr. Wolfgang,

Thank you for the feedback. I was wondering why meta-analysts did not
exhibit standard errors instead of confidence intervals in graphs. I can
understand the importance of showing that CIs did not include zero, but
standard errors can be more informative when comparing subgroups of a
moderator. This is just a curiosity.

Best wishes,

Rafael.

Em qua, 3 de jun de 2020 às 05:02, Viechtbauer, Wolfgang (SP) <
wolfgang.viechtbauer using maastrichtuniversity.nl> escreveu:

> Dear Rafael,
>
> What specifically do you mean by "this practice"? Presenting estimated
> (average) effects with their CIs when subgrouping the studies based on some
> categorical variable? Indeed, one cannot directly infer based on the CIs
> whether the subgroups are actually different from each other. For this, one
> should conduct a proper test of subgroup differences. One can also directly
> test whether the difference between two effects is significant or not or
> present an estimate of the difference between two effects with a
> corresponding CI (and if that CI excludes 0, then one knows that the test
> of the difference is significant at alpha = (100 - CI level)/100). But I
> see nothing generally wrong with the practice of presenting subgroup
> effects with CIs.
>
> Best,
> Wolfgang
>
> >-----Original Message-----
> >From: Rafael Rios [mailto:biorafaelrm using gmail.com]
> >Sent: Wednesday, 03 June, 2020 5:27
> >To: Viechtbauer, Wolfgang (SP)
> >Cc: r-sig-meta-analysis using r-project.org
> >Subject: Re: Overlapping CIs with significant difference among subgroups
> >
> >Dear Dr. Wolfgang,
> >
> >Thank you very much! Since confidence intervals are not very informative
> to
> >exhibit diferences between subgroups, why is this practice so common among
> >meta-analysts? Why not to present standard errors instead of CIs?
> >
> >Best wishes,
> >
> >Rafael.
> >
> >Em ter, 2 de jun de 2020 às 03:48, Viechtbauer, Wolfgang (SP)
> ><wolfgang.viechtbauer using maastrichtuniversity.nl> escreveu:
> >Dear Rafael,
> >
> >CIs can overlap and yet the difference between the two levels can be
> >significant. See, for example:
> >
> >https://towardsdatascience.com/why-overlapping-confidence-intervals-mean-
> >nothing-about-statistical-significance-48360559900a?gi=b673a691634d
> >
> >https://www.psychologicalscience.org/observer/understanding-confidence-
> >intervals-cis-and-effect-size-estimation
> >
> >https://blog.minitab.com/blog/real-world-quality-improvement/common-
> >statistical-mistakes-you-should-avoid
> >
> >and many more (just google for "test difference overlapping confidence
> >intervals" or something along those lines). They don't talk about meta-
> >analysis per se, but it's the same principle.
> >
> >So, you can trust the test of the difference between the levels of the
> >moderators.
> >
> >Best,
> >Wolfgang
> >
> >>-----Original Message-----
> >>From: Rafael Rios [mailto:biorafaelrm using gmail.com]
> >>Sent: Monday, 01 June, 2020 21:54
> >>To: r-sig-meta-analysis using r-project.org; Viechtbauer, Wolfgang (SP)
> >>Subject: Overlapping CIs with significant difference among subgroups
> >>
> >>ATTACHMENT(S) REMOVED: dataset.csv | pruned_super-tree.tre | script.R
> >>
> >>Dear Wolfgang and All,
> >>
> >>I conducted a multilevel mixed-effects meta-analysis and found
> differences
> >>between levels of two moderators. I was expecting to find non-overlapped
> >>confidence intervals. However, I obtained overlapped confidence intervals
> >>for all subgroups. How can I interpret these results? In such situation,
> >>should I trust in the Q-test or in the CIs? I controlled for phylogenetic
> >>non-independence. Is there a chance of this approach affect the
> estimation
> >>of CIs using predict function? My dataset and script are attached.
> >>
> >>Best wishes,
> >>_______________________________________________________
> >>
> >>Prof. Dr. Rafael Rios Moura
> >>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
> >--
> >_______________________________________________________
>
-- 
_______________________________________________________

*Prof. Dr. Rafael Rios Moura*
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>

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