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

Mon, May 3, 2021 10:42 AM

Hi Gerta and Michael,
I am not sure to understand. I am not saying the the effect size are
different. They are comparable but of course differ in term of ci since the
number of studies, participants are different. I would like to know whether
we can make obtain an overall effect size while controlling for design. So
maybe the answer is no.
Thanks
Gladys

Le lun. 3 mai 2021 ? 19:11, Dr. Gerta R?cker <ruecker at imbi.uni-freiburg.de>
a ?crit :

Technically, you may conduct a meta-analysis of these two effects and
obtain something between. The question is how to interpret this.

Best,

Gerta

Am 03.05.2021 um 19:06 schrieb Michael Dewey:

Yes, exactly. After all if you show two things are different you
cannot say they are the same.

Michael

On 03/05/2021 15:59, Gladys Barragan-Jason wrote:

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

Le lun. 3 mai 2021 ? 14:36, Michael Dewey <lists at dewey.myzen.co.uk
<mailto:lists at dewey.myzen.co.uk>> a ?crit :

    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 ? 12:41, Michael Dewey

    <lists at dewey.myzen.co.uk <mailto:lists at dewey.myzen.co.uk>

     > <mailto:lists at dewey.myzen.co.uk

    <mailto:lists at dewey.myzen.co.uk>>> a ?crit :

     >
     >     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 at r-project.org

    <mailto:r-sig-meta-analysis at r-project.org>

     >     <mailto:r-sig-meta-analysis at r-project.org

    <mailto:r-sig-meta-analysis at r-project.org>>

     >      > <mailto:r-sig-meta-analysis at r-project.org

    <mailto:r-sig-meta-analysis at r-project.org>

     >     <mailto:r-sig-meta-analysis at r-project.org

    <mailto:r-sig-meta-analysis at 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//>

     >  <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>

     >  <https://sites.google.com/view/gladysbarraganjason/home

<https://sites.google.com/view/gladysbarraganjason/home>>>

     >      >
     >      > Station d'Ecologie Th?orique et Exp?rimentale (SETE)____
     >      >
     >      > CNRS de Moulis____
     >      >
     >      > image.pngimage.png____
     >      >
     >      >
     >      >
     >      >
     >      >

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     >      >
     >      >
     >      > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
     >      >
     >      > _______________________________________________
     >      > R-sig-meta-analysis mailing list
     >      > R-sig-meta-analysis at r-project.org

    <mailto:R-sig-meta-analysis at r-project.org>

     >     <mailto:R-sig-meta-analysis at r-project.org

    <mailto:R-sig-meta-analysis at r-project.org>>

     >      > https://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis

<https://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis>

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<https://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis>>

     >      >

     >
     >     --
     >     Michael
     > http://www.dewey.myzen.co.uk/home.html

    <http://www.dewey.myzen.co.uk/home.html>

     >     <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

<https://sites.google.com/view/gladysbarraganjason/home>>

     >
     > Station d'Ecologie Th?orique et Exp?rimentale (SETE)____
     >
     > CNRS de Moulis____
     >
     > image.pngimage.png____
     >
     >
     >

    --     Michael
    http://www.dewey.myzen.co.uk/home.html
    <http://www.dewey.myzen.co.uk/home.html>

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

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