[R-meta] unsigned effect sizes

[James Pustejovsky]

Thank you, Daniel and Wolfgang! All of the references you suggested look
very useful.

James

On Wed, Feb 16, 2022 at 2:59 AM Viechtbauer, Wolfgang (SP) <
wolfgang.viechtbauer using maastrichtuniversity.nl> wrote:

> Hi James,
>
> I think this is also related:
>
> https://doi.org/10.1207/s15327043hup1201_1
>
> Best,
> Wolfgang
>
> >-----Original Message-----
> >From: R-sig-meta-analysis [mailto:
> r-sig-meta-analysis-bounces using r-project.org] On
> >Behalf Of Daniel Noble
> >Sent: Saturday, 12 February, 2022 2:34
> >To: James Pustejovsky
> >Cc: R meta
> >Subject: Re: [R-meta] unsigned effect sizes
> >
> >ATTACHMENT(S) REMOVED: ATT00001.txt
> >
> >Hi James,
> >
> >A great question! Yes, this is something quite common in ecology and
> evolution
> >meta-analyses. There are some nice papers you may want to consult by Mike
> >Morrissey. Here are a few references.
> >
> >Morrissey, M. B. (2016). Meta-analysis of magnitudes, differences and
> variation
> >in evolutionary parameters. J. Evol. Biol. 29, 1862-1904.
> >
> >Morrissey, M. B. (2016).. Rejoinder: Further considerations for
> meta-analysis of
> >transformed quantities such as absolute values. J. Evol. Biol. ,
> 29: 1922–1931.
> >
> >Basically it involves transforming ‘post-analysis’ to a folded normal.
> I’ve used
> >it myself in a Bayesian context. It’s quite easy to do there. Hope this
> is useful
> >and what you’re thinking about.
> >
> >Cheers,
> >Dan
> >_______________
> >
> >Dr. Daniel Noble
> >Senior Lecturer
> >
> >Division of Ecology and Evolution (office W317),
> >Research School of Biology,
> >College of Science,
> >Robertson Building,
> >46 Sullivans Creek Road,
> >The Australian National University
> >Canberra, ACT 2600
> >Australia
> >
> > T +61 02 6125 0423
> >M +61 430 290 053
> >daniel.noble using anu.edu.au
> >Noble Lab Webpage: www.nobledan.com
> >RSB: https://biology.anu.edu.au
> >
> >CRICOS Provider #00120C
> >
> >On 12 Feb 2022, at 12:24 pm, James Pustejovsky <jepusto using gmail.com> wrote:
> >
> >Hi meta-analysis folks,
> >
> >I have a kind of vague question about something I've run across a few
> >times. There are some (perhaps rare) situations where investigators are
> >interested in the absolute magnitude of an effect but where the sign or
> >direction of the effect is arbitrary or not meaningful. Consequently,
> >meta-analysts of such effects might like to work with _unsigned_ effect
> >size estimates rather than the estimates that describe both magnitude and
> >direction. However, taking the absolute value of an estimate changes its
> >sampling distribution--potentially quite drastically!--in a way that would
> >make conventional meta-analytic models
> >(fixed/common/random/multi-level/multi-variate) perform rather poorly.
> >
> >Does anyone know of work on methods for synthesis of unsigned effects,
> that
> >actually account for the consequences of using absolute effect size
> >estimates?
> >
> >James
>

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