[R] Help conduction Egger's test

Viechtbauer Wolfgang (STAT) wolfgang.viechtbauer at maastrichtuniversity.nl
Mon May 12 22:58:41 CEST 2014


Yes, the 'traditional' Egger test is a weighted regression of the effect size estimates against their standard errors with weights s2/vi, where s2 is a multiplicative dispersion parameter. This is what you will get with:

regtest(x, model="lm", predictor="sei")

where 'x' is an object returned by the rma() function from a fixed/random-effects model.

An example:

### load BCG vaccine data
data(dat.bcg)

### calculate log relative risks and corresponding sampling variances
dat <- escalc(measure="RR", ai=tpos, bi=tneg, ci=cpos, di=cneg, data=dat.bcg)

### random-effects model
res <- rma(yi, vi, data=dat)

### classical Egger test
regtest(res, model="lm", predictor="sei")

Best,
Wolfgang

--   
Wolfgang Viechtbauer, Ph.D., Statistician   
Department of Psychiatry and Psychology   
School for Mental Health and Neuroscience   
Faculty of Health, Medicine, and Life Sciences   
Maastricht University, P.O. Box 616 (VIJV1)   
6200 MD Maastricht, The Netherlands   
+31 (43) 388-4170 | http://www.wvbauer.com   


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> On Behalf Of Sultan Malik
> Sent: Monday, May 12, 2014 20:03
> To: r-help at r-project.org
> Subject: [R] Help conduction Egger's test
> 
> Hi,
> 
> I am currently conducting a meta analyses and wish to carry out Egger's
> test. I was just wondering, does the weighted linear regression model
> proposed by Egger et al correspond to the "weighted regression with
> multiplicative dispersion" option in Metafor?
> 
> Many thanks
> 
> Sultan
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