[R-meta] Random-effects meta-analyses with inverse-variance weights cannot include studies with sample sizes of two?

[Viechtbauer, Wolfgang (SP)]

What kind of effect size measure would you compute based on this? And what would be the corresponding sampling variance?

Best,
Wolfgang

-----Original Message-----
From: Patrizio Tressoldi [mailto:patrizio.tressoldi using unipd.it] 
Sent: Thursday, 08 November, 2018 19:01
To: Viechtbauer, Wolfgang (SP); Michael Dewey; r-sig-meta-analysis using r-project.org
Subject: Re: [R-meta] Random-effects meta-analyses with inverse-variance weights cannot include studies with sample sizes of two?

Il 08/11/2018 16:31, Viechtbauer, Wolfgang (SP) ha scritto:
> I wonder what effect size / oucome measure can sensibly be computed based on two subjects. For example, for measures based on two groups (e.g., raw or standardized mean difference, risk difference, log risk/odds ratios), this would imply that there is a single subject in each group.
>
>
Precisely.
In this specific case, two single participants contributed to a
percentage of hits, e.g. .30 and .40

I expect that the sample estimation is quite poor, but I don't see any
impediment on obtaining an effect size, or not?

Best
Patrizio

--
Patrizio E. Tressoldi Ph.D.
Dipartimento di Psicologia Generale
Università di Padova
via Venezia 8
35131 Padova - ITALY
http://www.patriziotressoldi.it
https://orcid.org/0000-0002-6404-0058

Science of Consciousness Research Group
http://dpg.unipd.it/en/soc

Make war history
support http://www.emergency.it