Displaying 20 results from an estimated 41 matches for "metafor".

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2009 Aug 13

1

metafor random effects meta-analysis

Hello,
Great to see the new metafor package for meta-analysis.
I would like to perform a meta-analysis in which I initially calculate the intercept of the model with a nested random-effects structure. In lme, this would be
model<- lme(v3~1, random=~1|species/study, weights = varFixed(~Wt), method = "REML")
wher...

2009 Jul 24

1

metafor

I had found the author's (Wolfgang Viechtbauer) earlier meta-analytic code in R, MiMa, useful. so I have been exploring metafor using an example dataset from MiMa. metafor provides a lot more. However, MiMa provided parameter estimates, standard errors, z values, etc. for individual moderators in the meta-analysis, but I don't see how to obtain these from metafor. Have you any help about how to get this?
Frank
[...

2011 Oct 03

1

Meta-analysis of test statistics in "metafor" package?

...from a series of studies that tested for an interaction in a 2x2 anova.
I'd like to test whether the 2x2 interaction is significant in the
aggregate.
Similarly, I have a matrix of chi-square statistics that I'd like to
meta-analyze.
How can I input these test statistics into the "metafor" package and conduct
these meta-analyses? I see how to input raw data or standardizes effect
sizes (e.g., d) into "metafor", but not test statistics.
Best,
David
--
View this message in context: http://r.789695.n4.nabble.com/Meta-analysis-of-test-statistics-in-metafor...

2010 Nov 11

1

metafor: including phylogenetic non-independence among species?

Hello, Is it possible to include information about phylogenetic relatedness
among species (when species are replicates for each study within a
meta-analysis) in a meta-anlaysis in the metafor package?
Alternatively, I wonder if the method f Lajeunesse 2009 American Naturalist
has been adopted in R in any fashion?
Thanks, Scott Chamberlain
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2011 Aug 17

3

questions about "metafor" package

Hello,
I would like to do a meta-analysis with the package « metafor ». Ideally I would like to use a mixed model because I’m interested to see the effect of some moderators. But the data set I managed to collect from literature presents two limits.
- Firstly, for each observation, I have means for a treatment and for a control, but I don’t always have co...

2012 Sep 07

2

metafor package: study level variation

Hello. A quick question about incorporating variation due to study in the metafor package. I'm working with a particular data set for meta-analysis where some studies have multiple measurements. Others do not. So, let's say the effect I'm looking at is response to two different kinds of drug treatment - let's call their effect sizes T1 and T2. Some studies ha...

2011 Jan 12

1

metafor/ meta-regression

Hi I have tryed to do the meta-regression in metafor package, but I
would like to get the standardized coefficients for each variable, however in
command:
Ø res<-rma.uni (yi, vi,
method="REML", mods=~cota+DL+uso+gadiente+idade, data= turbidez)
I just have the coefficients no standardized (estimate) of the multiple
regression.
W...

2012 May 05

3

metafor

Dear users of metafor,
I am working on a meta-analysis using the metafor package. I have a
excel csv database that I am working with. I am interested in pooling
the effect measures for a particular subgroup (European women) in this
csv database. I am conducting both sub-group and meta-regression.
In subgroup-analyses,...

2012 Jan 14

1

metafor: weights computation in Mantel-Haenszel method

Dear R users,
In metafor 1.6-0, the Mantel-Haenszel method is implemented by the rma.mh() function. I have observed that the sum of the weights computed by weights(x) doesn't add to 100% when x is an object of class rma.mh. The consequences of this fact can be clearly seen when a forest diagram is drawn with forest(x),...

2013 Dec 12

1

refline in forest() {metafor}

...oticed
that refline sets a vertical line indicating the null hypothesis.
Is there a way to draw another vertical line, possibly dashed, centered on the
summary estimate?
Prof. Viechtbauer, if you happen to read this, I'd like to thank you for making
an excellent package. I have been using the metafor package to do my first
meta-analysis, having never used R before. The documentation is thorough and
intuitive.
Thanks,
John
John Williams
ALB Candidate
Harvard University Extension School
johnwilliams at fas.harvard.edu

2010 Dec 20

1

Metafor package

I have some question about metafor package.
I'm interest to perform a random effect meta-analysis of proportion
(single group summary of prevalence of disease in a population as
reported by different study)
It ask:
1. "PFT": The Freeman-Tukey double arcsine transformed proportion is
reported to be equal to 1...

2012 Sep 27

1

What to use for ti in back-transforming summary statistics from F-T double square-root transformation in 'metafor'

Hi Dr. Viechtbauer,
I'm doing meta-analysis using your package 'metafor'. I used the 'IRFT' to transform the incident rate. But when I tried to back-transform the summary estimates from function rma, I don't know what's the appropriate ti to feed in function transf.iirft. I searched and found your post about using harmonic mean for ni to back-trans...

2010 Jul 02

1

metafor and meta-analysis at arm-level

...level, the latter being the common way in which meta-analysis is
done.
By arm-level meta-analysis I mean one that accounts for data provided at
the level of the individual arms of each trial and that does not simply
derive the difference between arms and do the meta-analysis on that.
I am not sure metafor can do that, but hopefully someone more experienced
on it can clarify that to me. I can see that it can take data in both
forms, arm and trial level, but it looks as if the arm-level information
would be converted into trial one through escalc and the latter then used
for the meta-analysis. Is that...

2012 Dec 31

2

a problem for metafor package

Dear sir or madam
I want to know how to use "metafor"package do a meta anlysis, forest plot show the results of whole study and results of two subgroups
like this the forest plot show in the attachment.
looking forword to your reply
Regards and Cheers
Xudong Liu
School of Public Health and Primary Care
The Chinese University of Ho...

2013 Mar 02

1

Metafor "SMCR" Pre-Post Effect sizes

Dear all,
I am very grateful that Wolfgang Viechtbauer implemented the standardised mean change for dependent
groups. I was playing around a bit today, and I am not sure if I understand the "SMCR" procedure correctly. The documentation states that sd1i and sd2i are needed, but it seems to me that SMCR is ignoring sd2i (so Variances are not pooled). Instead, it uses sd1i (pre-test sd),

2011 Aug 05

1

Main-effect of categorical variables in meta-analysis (metafor)

Dear R-experts!
In a meta-analysis (metafor) I would like to assess the effect of two
categorical covariates (A & B) whereas they both have 4 levels.
Is my understanding correct that this would require to dummy-code (0,1) each
level of each covariate (A & B)?
However I am interested in the main-effects and the interaction of these tw...

2010 Aug 03

1

Metafor

This is a question of clarification.
IN 2009 Higgins, Thompson and Spiegelhalter (J R Statist Soc A 172:137-159) gave WinBUGs code to get credible intervals from random effects meta analysis for the prediction interval of a new study.
It appears that the predict.rma function creates approximate credible intervals (pending a function revision by the author) for that purpose.
Is my assumption

2013 Sep 15

1

FOSS licence with BuildVignettes: false

Dear All,
I have been checking the metafor package against R-devel.
R CMD check --as-cran metafor
yields one note:
FOSS licence with BuildVignettes: false
Yes, I have 'BuildVignettes: FALSE' in my DESCRIPTION file. I see at http://developer.r-project.org/blosxom.cgi/R-devel/NEWS:
Tue, 25 Jun 2013
CHANGES IN...

2012 Jul 24

1

Annotate forest plot 'forest.rma()' for meta-analysis with metafor package

Dear R-experts,
The forest.rma() function from the metafor package creates nice forest
plots for presenting the results of a meta-analysis. These plots can be
annotated for e.g. giving names to the columns. E.g. as in the
documentation of the package:
data(dat.bcg)
### meta-analysis of the log relative risks using a random-effects model
res <- rma(ai=...

2011 Apr 11

1

forest + igraph ?

Hello,
Is it possible to have two meta-plots in one graph (not par(mfrow=c(2,1))? But somthing like
library(metafor)
library("igraph")
if (interactive()) {
forest(dat.Treat$RR, ci.lb=dat.Treat$lower, ci.ub=dat.Treat$upper, xlab="Relative Risk",slab=dat.Treat$ID,refline=1)
forest(dat.Control$RR, ci.lb=dat.Control$lower, ci.ub=dat.Control$upper, xlab="Relative Risk",slab=d...