[R-meta] Subgroup analyses under the multi-level (3 level) meta-analysis model
Viechtbauer, Wolfgang (SP)
wo||g@ng@v|echtb@uer @end|ng |rom m@@@tr|chtun|ver@|ty@n|
Sun Mar 14 18:45:10 CET 2021
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One level is the reference level (namely 'Corr') and you get three contrasts with this reference level. Please see:
>From: Saya Fujita [mailto:sayakaf.p using gmail.com]
>Sent: Sunday, 14 March, 2021 17:43
>To: Viechtbauer, Wolfgang (SP)
>Subject: Re: Subgroup analyses under the multi-level (3 level) meta-analysis model
>Dear Professor Viechtbauer,
>Thank you very much for your prompt response!
>I ran the code using my original variables "Metrics" as factors.
>I can see it has 4 levels, but my regression results only show 3 factors.
>I am wondering why?
>The Metrics has 4 levels (Coupling, Flow, Graph, Corr) as seen below:
> Factor w/ 4 levels "Corr","Coupling",..: 1 1 1 1 1 1 1 1 1 1 ...
>Here's my codes:
> random = ~ 1 | PaperID/AnalysisID,
> tdist = TRUE,
> data = multi.data,
> method = "REML",
> mods = ~ Metrics)
>And the results are:
> estimate se tval pval ci.lb ci.ub
>intrcpt 0.8795 0.2458 3.5788 0.0005 0.3933 1.3658 ***
>MetricsCoupling -0.1432 0.2982 -0.4804 0.6318 -0.7332 0.4468
>MetricsFlow 0.1238 0.4307 0.2876 0.7742 -0.7283 0.9760
>MetricsGraph -0.0084 0.4257 -0.0196 0.9844 -0.8506 0.8339
>If you could kindly let me know whether I am doing something wrong, I would be so
>Thank you very much again!
>On 14/03/2021, 15:52, "Viechtbauer, Wolfgang (SP)"
><wolfgang.viechtbauer using maastrichtuniversity.nl> wrote:
> Dear Saya,
> You do not need to create these 'dummy variables' yourself. Just declare the
>variable that distinguishes the various subgroups as a factor and include it as a
>predictor via 'mods'. You also might want to read this:
> It's not focused on rma.mv() (i.e., it uses a simpler model), but the same
> >-----Original Message-----
> >From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces using r-project.org]
> >Behalf Of Saya Fujita
> >Sent: Sunday, 14 March, 2021 16:24
> >To: R-sig-meta-analysis using r-project.org
> >Subject: [R-meta] Subgroup analyses under the multi-level (3 level) meta-
> >Dear All,
> >I am conducting a 3-level multi-analysis, following this Bookdown.
> >I would like to run some sub-group analyses under this 3 level structure, and
> >can see in this bookdown (chapter 12.1) that if I use rma.mv function in
> >we need to create two variables/columns for each subgroup level. In the
> >this book down, the number of sub-groups was two: peer-review, dissertation,
> >makes sense that they coded 1 (yes) or 0 (no).
> >In my data I have more than two subgroups, and I wonder how I should input
> >data. I thought, if I have 4 subgroups for instance, I’d create 4 columns and
> >0 or 1 in each column, but that would group 3 different levels as 0 in one
> >and specifying one variable/column as a moderator in rma.mv using
> >the mods parameter would compare one subgroup with the other three subgroups
> >which is not what I want to do. Hope this makes sense!
> >I wonder if anyone here has done a subgroup analysis for multiple subgroup
> >comparisons, maintaining the 3 level structure of a multi-level meta-
> >Could I ask how you did the analysis?
> >Thank you very much in advance, and I apologise if it’s a very simple/naïve
> >Many thanks,
> >Sayaka Kidby (Fujita)| PhD candidate, Marie Skłodowska-Curie Early Career
> >Researcher [she/her]
> >Psychology | Lancaster University
> >s.kidby using lancaster.ac.uk
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