[R-meta] Compiling different design in the same met-analysis

[Gladys Barragan-Jason]

Okay, so you can't obtain an overall effect size while controlling for
design?

Le lun. 3 mai 2021 à 14:36, Michael Dewey <lists using dewey.myzen.co.uk> a
écrit :

> If you include a moderator you do not get an overall effect because by
> including it you are effectively saying there is no single overall effect.
>
> On 03/05/2021 12:24, Gladys Barragan-Jason wrote:
> > Hi Michael,
> > Thanks a lot for your quick response. Here are answers and other
> > questions below.
> >
> > Le lun. 3 mai 2021 à 12:41, Michael Dewey <lists using dewey.myzen.co.uk
> > <mailto:lists using dewey.myzen.co.uk>> a écrit :
> >
> >     Dear Gladys
> >
> >     Comments in-line
> >
> >     On 03/05/2021 08:13, Gladys Barragan-Jason wrote:
> >      > Dear all,
> >      >
> >      > I am doing a meta-analysis on experimental data on the impact on
> >      > several behavioral interventions including both *pre-post studies*
> >      > (measurement of a trait before and after the intervention) *and
> >     control
> >      > vs. treatment studies *(measurement after a control intervention
> vs.
> >      > measurement after the intervention).
> >
> >     So the first design just has one group which is measured twice and
> the
> >     second design has two parallel groups which are each measured once?
> >
> >
> > Exactly!
> >
> >
> >      > I am interested in the effect size of each type of intervention
> on a
> >      > specific trait that is common to all studies.
> >      >
> >      > I would like to know whether it is correct to compile all studies
> >     from
> >      > one type of intervention (whatever the type of comparisons:
> >     pre-pot and
> >      > control vs. treatment group together) with pre- and control being
> as
> >      > control and post and treatment being as treatment.
> >      >
> >
> >     I do not think that is going to work well. Although the two designs
> >     could be considered as estimating the same effect their variability
> >     should be very different since in design 1 you have reduced the
> effect
> >     of individual variability. If you do include both designs in one
> >     analysis I would have thought it mandatory to include a moderator
> with
> >     two levels for design.
> >
> > This makes sense. When I do this, I then obtain two effect sizes (one
> > for each design); (in having mods=~design-1). Do you know how I can get
> > the overall effect size?
> >
> >
> >      > I have a second question about how to thank the
> >      > r-sig-meta-analysis using r-project.org
> >     <mailto:r-sig-meta-analysis using r-project.org>
> >      > <mailto:r-sig-meta-analysis using r-project.org
> >     <mailto:r-sig-meta-analysis using r-project.org>> list for all their help
> >      > (acknowledgements in a paper).
> >
> >     I would have thought the URL
> >     https://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis//
> >     <https://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis//>
> >     was better. How to do this will also depend on custom and practice in
> >     your scientific discipline, some journals in mine require people who
> >     are
> >     acknowledged to give their consent.
> >
> >
> > Ok! Thanks a lot!
> >
> > Best,
> > Gladys
> >
> >
> >     Michael
> >
> >      >
> >      > Thanks a lot for your help!
> >      >
> >      > Have a great day,
> >      >
> >      > Gladys
> >      >
> >      > --
> >      >
> >      > ------------------------------------------
> >      >
> >      > Gladys Barragan-Jason, PhD. ____ Website
> >      > <https://sites.google.com/view/gladysbarraganjason/home
> >     <https://sites.google.com/view/gladysbarraganjason/home>>
> >      >
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> >     --
> >     Michael
> >     http://www.dewey.myzen.co.uk/home.html
> >     <http://www.dewey.myzen.co.uk/home.html>
> >
> >
> >
> > --
> >
> > ------------------------------------------
> >
> > Gladys Barragan-Jason, PhD. ____ Website
> > <https://sites.google.com/view/gladysbarraganjason/home>
> >
> > Station d'Ecologie Théorique et Expérimentale (SETE)____
> >
> > CNRS de Moulis____
> >
> > image.pngimage.png____
> >
> >
> >
>
> --
> Michael
> http://www.dewey.myzen.co.uk/home.html
>

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