Displaying 20 results from an estimated 1000 matches similar to: "Main-effect of categorical variables in meta-analysis (metafor)"
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=tpos, bi=tneg, ci=cpos, di=cneg,
2011 Jul 18
1
Extract confidence intervals from rma object (metafor package)
Dear R-experts!
I am working on some meta-analysis using the metafor package. I would like
to extract values of the confidence intervals of the effect sizes of the
single studies from an rma object. Those values are printed out when
plotting a forest plot using the forest function on the rma object, however
I was not able to locate them.
Many thanks for your help!
Jokel
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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.
What I need to do?
Thanks
Fernanda Melo
2013 Jan 19
1
dummy encoding in metafor
Hi,
I am quite new to R and in need of some advice. I am trying to conduct a meta regression over a some studies with about 7 mod variables which I have to dummy encode.
I have found the following piece of code in the manual for the metafor library:
### manual dummy coding of the allocation factor
alloc.random <- ifelse(dat$alloc == "random", 1, 0)
alloc.alternate <-
2013 Mar 19
1
Error when adding lines to a plot using the mixed-effect model and metafor package
Hi,
I am a student using R for my final year project, with the metafor package being particularly helpful. I have been following the steps laid out in the manual 'Conducting Meta-analysis in R with the Metafor package' (Viechtbauer, 2010) and applying it to my own data of infected Anopheles mosquitoes across Africa.
In particular, I am attempting to apply a mixed-effect model to my data
2012 Aug 02
2
metafor- interpretation of moderators test for raw proportions
Hello metafor users,
I'm using metafor to perform a single-effect summary estimate of the raw
proportion of patients experiencing a post-operative complication, and I'm
interested in seeing if this proportion differs between the three most
commonly used surgical techniques. The software is working as expected, but
I would like to double check on the interpretation of my mixed-effect model
2010 Mar 02
1
add a header to a forest plot (metafor)
Dear R-community,
I'm currently trying to assemble a forest plot using the "forest" function
from package "metaphor".
Works well. Even the regular "main"-argument works for adding a title to the
graph.
However, I would like to add one top row which explains the nature of the
columns. Very much like the usual header in spreadsheet programs.
For example:
2011 Dec 10
3
Overlaying density plot on forest plot
Dear R User,
Please, I am new to R. I want to overlay density plot for predictive interval pooled result in meta-analysis. http://addictedtor.free.fr/graphiques/graphcode.php?graph=114
Regards
Frank Peter
2011 Jul 27
1
Converting F-value from ANOVA to cohen's d in meta-analysis (metafor-package)
Dear R-experts!
Running a meta-analysis (using the magnificent metafor-package), I use
cohen's d as a main outcome measure in a random-effects model.
For most of the samples cohen's d is derived form a comparison of two groups
(A & B). However some studies report results from an ANOVA (one-factor with
three levels: C,D,E) whereas two groups (C,D) correspond to one group in the
other
2013 Jan 05
3
package metafor: error when setting 'col' and 'at' for a forest plot
I am using metafor to create forest plots. This code gives me the expected
plot (setting x axis tick marks):
forest(forest$OR, ci.lb=forest$Low, ci.ub=forest$High, at=log(c(.05, .25,
1, 10)), slab=forest$SNP, atransf=exp)
As does this (setting colors):
forest(forest$OR, ci.lb=forest$Low, ci.ub=forest$High, col=c(1,2,3),
slab=forest$SNP, atransf=exp)
But if I try to set both 'at' and
2013 Mar 14
3
Create patterns within a plot?
Dear All,
As an attempt to highlight the overall pattern in a Forest plot, I would like to "highlight" the area around HR=1. I cannot find any simple tools for painting a grey ribbon between 0.9 and 1.1. Any suggestions?
Thank you in advance!
Cheers, Patrik
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2011 Sep 08
1
predict.rma (metafor package)
Hi
(R 2.13.1, OSX 10.6.8)
I am trying to use predict.rma with continuous and categorical variables. The argument newmods in predict.rma seems to handle coviariates, but appears to falter on factors. While I realise that the coefficients for factors provide the answers, the goal is to eventually use predict.rma with ANCOVA type model with an interaction.
Here is a self contained example
2010 Jan 04
1
metafor: using mixed models
Dear all,
I'm currently applying a mixed model approach to meta analysis using the
package metafor. I use the "model.matrix()" function to create dummy
variables. The option btt gives me the combined test for the dummies.
Problem is, I don't know which indices I have to use, and can't really
figure it out from the help file and the examples. I use following code :
X <-
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), which calls weights(x) (or more precisely, the method weights.rma.mh()
2009 Dec 04
1
z to r transformation within print.rma.uni and forest from the package metafor
Dear R community,
I'm using the ,metafor'-package by Wolfgang Viechtbauer (Version: 0.5-5) to
calculate random-effects meta-analyses using Correlations and Sample Sizes
as the raw data.
(By the way: Really a nice piece of work, Wolfgang! Thanks heaps.)
I specified the "rma.uni' function so that it looks like this:
MAergebnis<-rma.uni(ri=PosOutc, ni=N,
2012 Aug 09
1
Factor moderators in metafor
I'm puzzled by the behaviour of factors in rma models, see example and
comments below. I'm sure there's a simple explanation but can't see it...
Thanks for any input
John Hodgson
------------------------------------- code/selected output -----------------
library(metafor)
## Set up data (from Lenters et al A Meta-analysis of Asbestos and Lung
Cancer...
##
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 have multiple
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, I have stratified the database to create a
separate csv file just for European
2011 Jan 12
1
Metafor vs Meta vs Spreadsheet: wrong numbers
Hello,
I experimented the Metafor and Meta packages in the scope of replacing Excel
for meta-analysis. I performed the first working example provided in Michael
Borenstein's book "Introduction to Meta-Analysis" with Excel, Metafor and Meta.
The numbers given by my spreadsheet, which I validated from Borenstein's book,
conrespond quite closely to those given by Meta, but
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")
where multiple effects sizes are measured for some studies and more than