Does Jamovi use Cohen's d as standardized mean difference?

Discuss statistics related things
Post Reply
frbp
Posts: 4
Joined: Wed Jan 19, 2022 2:54 pm

Does Jamovi use Cohen's d as standardized mean difference?

Post by frbp »

I have been using Jamovi version 1.6.23 for meta-analysis, with a random-effects model fitted to the data, and using the standardized mean difference (SMD) as the outcome measure. Does anyone know if the SMD that Jamovi provides is exactly Cohen’s d? or is the SMD given by Jamovi calculated with a different formula (different from Cohen's d)?
User avatar
jonathon
Posts: 2609
Joined: Fri Jan 27, 2017 10:04 am

Re: Does Jamovi use Cohen's d as standardized mean differenc

Post by jonathon »

is this for the MAJOR module? it's helpful if you mention the module you're using.

i'm not actually sure what the SMD is.

cheers

jonathon
frbp
Posts: 4
Joined: Wed Jan 19, 2022 2:54 pm

Re: Does Jamovi use Cohen's d as standardized mean differenc

Post by frbp »

Yes, this would be for the MAJOR module. I don't know what estimator is used for the calculation of the standardized mean difference (SMD) in this module. SMDs are usually estimated by Cohen's d or Hedges' g. I was wondering if someone knew how SMDs are estimated in the MAJOR module of Jamovi.

Cheers,

Francisco
User avatar
MAgojam
Posts: 421
Joined: Thu Jun 08, 2017 2:33 pm
Location: Parma (Italy)

Re: Does Jamovi use Cohen's d as standardized mean differenc

Post by MAgojam »

frbp wrote: Does anyone know if the SMD that Jamovi provides is exactly Cohen’s d? or is the SMD given by Jamovi calculated with a different formula (different from Cohen's d)?
Hey Francisco,
Standardized Mean Difference (SMD) was one of the first effect dimensions used in published meta-analyzes (Larry V. Hedges & Olkin 1985) and remains widely used.
There are many ways to calculate the SMD for a data set.
In jamovi the MAJOR module imports/uses Wolfgang Viechtbau's metafor R package.

It's called Hedge's g (Hedges, 1981), in the metafor package, the default value for SMD.

Cheers, Maurizio
frbp
Posts: 4
Joined: Wed Jan 19, 2022 2:54 pm

Re: Does Jamovi use Cohen's d as standardized mean differenc

Post by frbp »

Hi Maurizio,

Thank you very much for the clarification.

Cheers,

Francisco
Post Reply