[R-meta] min sample size for three random variables in meta-analysis
Michael Dewey
||@t@ @end|ng |rom dewey@myzen@co@uk
Fri Jul 22 14:19:56 CEST 2022
Dear Jose
Unfortunately this is a plain text list and your post in HTML has got
scrambled so as to be almost unreadable.
Just to clarify, when you say small sample size do you mean a small
number of primary studies or that individual studies were based on small
numbers? Is k the number of primary studies?
Michael
On 21/07/2022 15:42, Jose Valdebenito wrote:
> Hi,
>
> I am conducting a (multi-level) meta-analysis with some sample sizes that
> are a bit small.
>
> I was wondering if there is a kind of rule of thumb regarding minimum
> sample size number, and the maximum number of random variables I can add to
> the models.
>
> I would like to add 3 (as suggested in Cinar et al. Methods Ecol Evol.
> 2022;13:383–95), but I am afraid that might incur in overparameterization
> if I have, say k=10?
>
> These are the random variables:
> -Phylogenetic relatedness
> -Study ID
> -Species ID
>
> Also, would it be any different in a meta-regression?
>
> Here I paste the model and dataset so you can see:
>
> m2 <- rma.mv(L_d, L_v,
> data = df,
> random = list(~1|species_2,
> ~1|study.ID,
> ~1|spp),
> R = list(species_2 = vcv), digits = 3)
>
>
>> head(df, 10)
> species_2 spp
> study.ID L_d L_v
> Grus_americana Grus_americana
> p.b.4 0.000 0.135
> Loxia_leucoptera Loxia_leucoptera
> p.b.15 1.057 0.068
> Centrocercus_urophasianus Centrocercus_urophasianus p.b.60
> 0.384 0.021
> Pica_nuttalli Pica_nuttalli
> p.b.8 -2.042 0.037
> Acrocephalus_paludicola Acrocephalus_paludicola 17
> 0.000 0.068
> Acrocephalus_paludicola Acrocephalus_paludicola 17
> -4.978 0.334
> Lepidothrix_coronata Lepidothrix_coronata 20
> -2.043 0.088
> Erithacus_rubecula Erithacus_rubecula 35
> -1.723 0.401
> Fringilla_coelebs Fringilla_coelebs
> 35 -2.697 0.111
> Parus_caeruleus Parus_caeruleus 35
> 4.862 0.559
>
>
> Thanks in advance,
> Joe
>
> [[alternative HTML version deleted]]
>
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--
Michael
http://www.dewey.myzen.co.uk/home.html
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