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[R-meta] Covariance-variance matrix when studies share multiple treatment x control comparison

You are still using 'residuals' as the outcome. Don't do that. Just use the Hedges' g values as the outcome. Also, you should specify the correct V matrix (I think you called it VCV in an earlier post). So, for example:

rma.mv(hedged ~ precision.2, VCV, data=MHF, random = list(~ 1 | Study, ~1 | Id),  subset=(Spatial.scale.2=="Fragmentation scale"))

I haven't looked at your other post in detail, but 'random = ~ factor(x) | Study/Id' doesn't actually work (at least not in the way you think it does). Please update your metafor installation to get an error that will inform you of this. Instead, random = list(~factor(x)|Study, ~factor(x)|Id) is indeed the correct way to specify two '~ inner | outer' terms.

Best,
Wolfgang

-----Original Message-----
From: Ju Lee [mailto:juhyung2 at stanford.edu] 
Sent: Friday, 27 September, 2019 16:46
To: James Pustejovsky
Cc: Viechtbauer, Wolfgang (SP); r-sig-meta-analysis at r-project.org
Subject: Re: Covariance-variance matrix when studies share multiple treatment x control comparison

Dear James,?Wolfgang,

Thank you very much for this information.
I have one question extending from this is: While I run my main mixed modes always using var-covar. matrix (to account for shared study groups within each study),?
it is acceptable that my egger-like regression does not incorporate this structure, but rather just use sqrt(1 / n1 + 1 / n2)? as precision (instead of sqrt(diag(v.c.matrix)) like?Wolfgang suggested as one possibility) and use p-value for precision term (precision.2 which is p=0.2382) to determine the asymmetry?

prec.<-function(CN,TN){
? pr<-sqrt((1 / CN) + (1/TN))
? return(pr)
}
precision.2<-prec.(MHF$n.t, MHF$n.c)
Multivariate Meta-Analysis Model (k = 285; method: REML)
Variance Components:?
? estim ? ?sqrt ?nlvls ?fixed ?factor
sigma^2.1 ?0.4255 ?0.6523 ? ? 73 ? ? no ? Study
sigma^2.2 ?0.3130 ?0.5595 ? ?285 ? ? no ? ? ?Id
Test for Residual Heterogeneity: 
? QE(df = 283) = 1041.1007, p-val < .0001
Test of Moderators (coefficient(s) 2): 
? QM(df = 1) = 1.3909, p-val = 0.2382

Model Results:
? estimate ? ? ?se ? ? zval ? ?pval ? ?ci.lb ? ci.ub ? 
intrcpt ? ? ? ?0.0529 ?0.1617 ? 0.3274 ?0.7433 ?-0.2640 ?0.3699 ? 
precision.2 ? -0.0668 ?0.0567 ?-1.1794 ?0.2382 ?-0.1779 ?0.0442? ?
---
? Signif. codes: ?0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1 


Thank you very much, both of you.
Best,
JU

p.s.?Wolfgang, I think I figured out what went wrong with how I specified my random effects in my previous e-mail. Specifying it as?random=list(~factor(x)|Study, ~factor(x)|Id)?instead of random= ~factor(x)|Study/Id generates results that makes sense to me now. Please let me know if this is correct way I should be coding.

Thread (16 messages)

Ju Lee Covariance-variance matrix when studies share multiple treatment x control comparison Sep 18 Wolfgang Viechtbauer Covariance-variance matrix when studies share multiple treatment x control comparison Sep 18 Ju Lee Covariance-variance matrix when studies share multiple treatment x control comparison Sep 18 Ju Lee Covariance-variance matrix when studies share multiple treatment x control comparison Sep 18 Wolfgang Viechtbauer Covariance-variance matrix when studies share multiple treatment x control comparison Sep 24 Ju Lee Covariance-variance matrix when studies share multiple treatment x control comparison Sep 25 Wolfgang Viechtbauer Covariance-variance matrix when studies share multiple treatment x control comparison Sep 26 Ju Lee Covariance-variance matrix when studies share multiple treatment x control comparison Sep 26 Wolfgang Viechtbauer Covariance-variance matrix when studies share multiple treatment x control comparison Sep 26 James Pustejovsky Covariance-variance matrix when studies share multiple treatment x control comparison Sep 26 Ju Lee Covariance-variance matrix when studies share multiple treatment x control comparison Sep 26 Ju Lee Covariance-variance matrix when studies share multiple treatment x control comparison Sep 26 James Pustejovsky Covariance-variance matrix when studies share multiple treatment x control comparison Sep 26 Ju Lee Covariance-variance matrix when studies share multiple treatment x control comparison Sep 27 Wolfgang Viechtbauer Covariance-variance matrix when studies share multiple treatment x control comparison Sep 27 Ju Lee Covariance-variance matrix when studies share multiple treatment x control comparison Sep 27